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Journal Cover International Journal of Epidemiology
  [SJR: 4.381]   [H-I: 145]   [150 followers]  Follow
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Print) 0300-5771 - ISSN (Online) 1464-3685
   Published by Oxford University Press Homepage  [370 journals]
  • Cohort Profile: Stress in Pregnancy (SIP) Study
    • Authors: Finik J; Nomura Y.
      PubDate: 2017-11-06
  • Forty four
    • Authors: Tsabari A.
      Abstract: You are as dead on my forty-fourth birthday
      PubDate: 2017-10-11
  • Data Resource Profile: The Nordic Obesity Surgery Cohort (NordOSCo)
    • Authors: Tao W; Artama M, von Euler-Chelpin M, et al.
      PubDate: 2017-10-10
  • The epidemiological challenge of traditional chronic disease risk factors
           in emerging economies
    • Authors: Greenberg H.
      PubDate: 2017-10-06
  • Commentary: Intrauterine exposure to artificially sweetened beverages and
           offspring adiposity: is this the tip of the iceberg'
    • Authors: Hardy L.
      PubDate: 2017-09-12
  • Serious danger signals: Response to: The effect of neonatal vitamin A
           supplementation on morbidity and mortality at 12 months: a randomized
    • Authors: Benn C; Fisker A, Aaby P.
      PubDate: 2017-09-07
  • Response to: ‘Serious danger signals’, response to: ‘The effect of
           neonatal vitamin A supplementation on morbidity and mortality at 12
           months: a randomized trial’
    • Authors: Smith E; Muhihi A, Mshamu S, et al.
      Abstract: Christine Benn and colleagues suggest that maternal vitamin A supplementation (MVAS) cannot explain the heterogeneity of results shown across neonatal vitamin A supplementation (NVAS) trials. We agree that maternal vitamin A status may not explain the entirety of the heterogeneity of effect across trials. However, we found significant effect modification by MVAS in our cohort, and also illustrated that maternal vitamin A status (defined by both MVAS and dietary intake) shows a similar trend; the biggest reduction in mortality with NVAS was found among the subgroup of infants whose mothers had not received supplemental vitamin A and also had inadequate vitamin A in their diets. The published body of evidence also lends support to this hypothesis. To date, there have been 11 randomized trials conducted in eight countries. Three of the four studies that found benefit of NVAS were conducted in populations classified as having moderate to severe vitamin A deficiency.1–3 Given our results, the larger body of evidence, and biological plausibility, we argue that maternal vitamin A status is at least one of the reasonable explanations for the heterogeneity of effect of NVAS on infant mortality.
      PubDate: 2017-09-07
  • Commentary: Does early cannabis initiation reduce educational
           attainment' New contributions and unanswered questions
    • Authors: Cerdá M.
      PubDate: 2017-09-07
  • A guide to evaluating linkage quality for the analysis of linked data
    • Authors: Harron K; Doidge J, Knight H, et al.
      Abstract: Linked datasets are an important resource for epidemiological and clinical studies, but linkage error can lead to biased results. For data security reasons, linkage of personal identifiers is often performed by a third party, making it difficult for researchers to assess the quality of the linked dataset in the context of specific research questions. This is compounded by a lack of guidance on how to determine the potential impact of linkage error. We describe how linkage quality can be evaluated and provide widely applicable guidance for both data providers and researchers. Using an illustrative example of a linked dataset of maternal and baby hospital records, we demonstrate three approaches for evaluating linkage quality: applying the linkage algorithm to a subset of gold standard data to quantify linkage error; comparing characteristics of linked and unlinked data to identify potential sources of bias; and evaluating the sensitivity of results to changes in the linkage procedure. These approaches can inform our understanding of the potential impact of linkage error and provide an opportunity to select the most appropriate linkage procedure for a specific analysis. Evaluating linkage quality in this way will improve the quality and transparency of epidemiological and clinical research using linked data.
      PubDate: 2017-09-07
  • Software Application Profile: Opal and Mica: open-source software
           solutions for epidemiological data management, harmonization and
    • Authors: Doiron D; Marcon Y, Fortier I, et al.
      Abstract: MotivationImproving the dissemination of information on existing epidemiological studies and facilitating the interoperability of study databases are essential to maximizing the use of resources and accelerating improvements in health. To address this, Maelstrom Research proposes Opal and Mica, two inter-operable open-source software packages providing out-of-the-box solutions for epidemiological data management, harmonization and dissemination.ImplementationOpal and Mica are two standalone but inter-operable web applications written in Java, JavaScript and PHP. They provide web services and modern user interfaces to access them.General featuresOpal allows users to import, manage, annotate and harmonize study data. Mica is used to build searchable web portals disseminating study and variable metadata. When used conjointly, Mica users can securely query and retrieve summary statistics on geographically dispersed Opal servers in real-time. Integration with the DataSHIELD approach allows conducting more complex federated analyses involving statistical models.AvailabilityOpal and Mica are open-source and freely available at [] under a General Public License (GPL) version 3, and the metadata models and taxonomies that accompany them are available under a Creative Commons licence.
      PubDate: 2017-09-02
  • Offspring risk of obesity in childhood, adolescence and adulthood in
           relation to gestational diabetes mellitus: a sex-specific association
    • Authors: Li S; Zhu Y, Yeung E, et al.
      Abstract: BackgroundAnimal data suggest sexually dimorphic programming of obesity in response to altered intrauterine environment, but the longitudinal impact of gestational diabetes mellitus (GDM) on sex-specific risk of offspring obesity in humans is unclear.MethodsWe conducted a prospective analysis of 15 009 US individuals (7946 female and 7063 male) from the Growing-Up Today Study, who were followed from 1996 (ages 9–14 years) through 2010. Height and weight from validated questionnaires were used to derive body mass index (BMI) at different ages. Obesity during childhood (< 18 years) and adulthood (≥ 18 years) were defined using the International Obesity Task Force and the World Health Organization criteria. GDM exposure was identified through self-reported questionnaires from mothers. Relative risks were estimated using multivariable log-binomial regression models with generalized estimating equations accounting for clustering within the same family.ResultsMale offspring born from pregnancies complicated by GDM had higher BMI compared with non-GDM offspring and had increased risk of obesity; the adjusted relative risk [RR, 95% confidence interval (CI)] was 1.47 (1.11–1.95) for all age groups, 1.59 (1.05–2.41) for late childhood, 1.48 (1.06–2.06) for adolescence and 1.39 (1.00–1.94) for early adulthood. No significant association between obesity and maternal GDM was observed among female participants (RR = 0.97, 95% CI: 0.71–1.33).ConclusionsThe association of GDM with offspring obesity from late childhood through early adulthood may differ by sex; a significant association was observed among male but not female offspring.
      PubDate: 2017-08-09
  • Association between pre-pregnancy overweight and obesity and children’s
           neurocognitive development: a systematic review and meta-analysis of
           observational studies
    • Authors: Álvarez-Bueno C; Cavero-Redondo I, Lucas-de la Cruz L, et al.
      Abstract: First published online: 13 July 2017, Int J Epidemiol, 2017, doi:
      PubDate: 2017-08-07
  • High adherence to the Mediterranean diet is associated with cardiovascular
           protection in higher but not in lower socioeconomic groups: prospective
           findings from the Moli-sani study
    • Authors: Bonaccio M; Di Castelnuovo A, Pounis G, et al.
      Abstract: BackgroundIt is uncertain whether the cardiovascular benefits associated with Mediterranean diet (MD) may differ across socioeconomic groups.MethodsProspective analysis on 18991 men and women aged ≥35 years from the general population of the Moli-sani cohort (Italy). Adherence to MD was appraised by the Mediterranean diet score (MDS). Household income (euros/year) and educational level were used as indicators of socioeconomic status. Hazard ratios (HR) were calculated by multivariable Cox proportional hazard models.ResultsOver 4.3 years of follow-up, 252 cardiovascular disease (CVD) events occurred. Overall, a two-point increase in MDS was associated with 15% reduced CVD risk (95% confidence interval: 1% to 27%). Such association was evident in highly (HR = 0.43; 0.25–0.72) but not in less (HR = 0.94; 0.78–1.14) educated subjects (P for interaction = 0.042). Similarly, CVD advantages associated with the MD were confined to the high household income group (HR = 0.39; 0.23–0.66, and HR = 1.01; 0.79–1.29 for high- and low-income groups, respectively; P for interaction = 0.0098). In a subgroup of individuals of different socioeconomic status but sharing similar MDS, diet-related disparities were found as different intakes of antioxidants and polyphenols, fatty acids, micronutrients, dietary antioxidant capacity, dietary diversity, organic vegetables and whole grain bread consumption.ConclusionsMD is associated with lower CVD risk but this relationship is confined to higher socioeconomic groups. In groups sharing similar scores of adherence to MD, diet-related disparities across socioeconomic groups persisted. These nutritional gaps may reasonably explain at least in part the socioeconomic pattern of CVD protection from the MD.
      PubDate: 2017-08-01
  • Antiretroviral therapy use during pregnancy and adverse birth outcomes in
           South African women
    • Authors: Malaba T; Phillips T, Le Roux S, et al.
      Abstract: BackgroundStudies of antiretroviral therapy (ART) use during pregnancy in HIV-infected women have suggested that ART exposure may be associated with adverse birth outcomes. However, there are few data from sub-Saharan Africa where HIV is most common, and few studies involving the World Health Organization’s (WHO’s) recommended first-line regimens.MethodsWe enrolled consecutive HIV-infected pregnant women and a comparator cohort of uninfected women at a primary-level antenatal care facility in Cape Town, South Africa. Gestational assessment combined clinical history, examination and ultrasonography; outcomes included preterm (PTD), low birthweight (LBW) and small for gestational age (SGA) deliveries. In analysis we compared birth outcomes between HIV-infected and -uninfected women, and HIV-infected women who initiated ART before vs during pregnancy.ResultsIn 1554 women (mean age 29 years) with live singleton births at time of analysis, 82% were HIV-infected, 92% of whom received a first-line regimen of tenofovir, emtricitabine and efavirenz. Overall, higher levels of PTD [22% vs 13%; odds ratio (OR) 1.94, 95% confidence interval (CI): 1.34, 2.82] and LBW (14% vs 9%; OR 1.62, 95% CI: 1.05, 2.29) were observed in HIV-infected vs uninfected women, although SGA deliveries were similar (9% vs 11%; OR 1.06, 95% CI: 0.71, 1.61). Adjusting for demographic characteristics and HIV disease measures, HIV-infected (vs HIV-uninfected) women had persistently increased odds of PTD [adjusted odds ratio (AOR) 2.03; CI 1.33, 3.10]; associations with LBW were attenuated (AOR 1.47; CI 0.90, 2.40). Among all HIV-infected women, there appeared to be no association between the timing of ART initiation (before or during pregnancy) and adverse birth outcomes.ConclusionsThese findings suggest that current WHO-recommended ART regimens appear relatively safe in pregnancy, although more data are required to understand the aetiology of preterm delivery in HIV-infected women using ART.
      PubDate: 2017-07-28
  • Encephalitis after influenza and vaccination: a nationwide
           population-based registry study from Norway
    • Authors: Ghaderi S; Størdal K, Gunnes N, et al.
      Abstract: BackgroundInfluenza is known to be associated with various neurological complications, including encephalitis. We conducted a registry-based study to assess the risk of encephalitis after influenza and A(H1N1)pdm09 vaccine.MethodsData from Norwegian national health registries during 2008–14 were linked using the unique personal identifiers given to all Norwegian residents (N = 5 210 519). Cox proportional-hazard models with time-varying variables were fitted to estimate hazard ratios (HRs) of encephalitis after influenza and A(H1N1)pdm09 vaccine, using the risk windows 0–7, 0–14, 0–30, 0–60, 0–90 and 0–180 days.ResultsIn Norway, 684 172 individuals received an influenza diagnosis and 2793 patients were hospitalized with encephalitis during 2008–14. The risk of encephalitis increased after influenza: HR, 7-day risk window: 47.8 (95% confidence interval (CI): 35.8–63.8), and the HR decreased for longer risk windows; HR, 180-day risk window: 3.8 (95% CI: 3.1–4.7). HR of encephalitis after influenza during the 2009 main pandemic wave using a 7-day risk window was 30.0 (95% CI: 10.8–83.2). We found no differences in the risk of encephalitis after the seasonal influenza compared with influenza during the 2009 main pandemic wave; HR, 7-day risk window: 1.3 (95% CI: 0.4–4.3). A(H1N1)pdm09 vaccine was not associated with the risk of encephalitis: HR, 14-day risk window: 0.6 (95% CI: 0.2–2.1).ConclusionsThere was an increased risk of encephalitis following influenza but not after A(H1N1)pdm09 vaccine. The risk of encephalitis was highest in the first few weeks after influenza.
      PubDate: 2017-07-27
  • Cohort Profile: The HIV Atlanta Veterans Affairs Cohort Study (HAVACS)
    • Authors: Guest J; Moanna A, Schlueter Wirtz S, et al.
      Abstract: First published online: 5 June 2016, Int J Epidemiol, 2016, doi:
      PubDate: 2017-07-26
  • HDSS Profile: The South East Asia Community Observatory Health and
           Demographic Surveillance System (SEACO HDSS)
    • Authors: Partap U; Young E, Allotey P, et al.
      PubDate: 2017-07-26
  • One Health and the Politics of Antimicrobial Resistance
    • Authors: Gilbert G.
      Abstract: One Health and the Politics of Antimicrobial Resistance.KahnLaura H.. Johns Hopkins University Press, 2016, pp. 192. $30. ISBN: 9781421420042.
      PubDate: 2017-07-24
  • Commentary: Multistage carcinogenesis and epidemiological studies of
    • Authors: Moolgavkar S.
      Abstract: First published online: 10 December 2015, Int J Epidemiol, 2015, doi:
      PubDate: 2017-07-24
  • Data Resource Profile: Danish Heart Statistics
    • Authors: Schmidt M; Andersen L, Friis S, et al.
      PubDate: 2017-07-21
  • Health Protection: Principles and Practice
    • Authors: Rubin G.
      Abstract: Health Protection: Principles and Practice.GhebrehewetSam, StewartAlex G., BaxterDavid, ShearsPaul, ConradDavid and KlinerMerav (eds). Oxford, UK: Oxford University Press, 2016.
      PubDate: 2017-07-17
  • Association between pre-pregnancy overweight and obesity and children’s
           neurocognitive development: a systematic review and meta-analysis of
           observational studies
    • Authors: Álvarez-Bueno C; Cavero-Redondo I, Lucas-de la Cruz L, et al.
      Abstract: BackgroundObesity and overweight during pregnancy have been negatively associated with fetal and offspring neurodevelopment. The aim of this systematic review and meta-analysis was to assess the effect of the relationship between pre-pregnancy overweight and obesity with children’s neurocognitive development.MethodsWe systematically searched MEDLINE, EMBASE, the Cochrane Library and the Web of Science databases from their inception through February 2017 for follow-up studies comparing the relationship between pre-pregnancy weight status and children’s cognition. The Mantel-Haenszel fixed-effects method was used to calculate pooled effect size (ES) values and their corresponding 95% confidence intervals (CIs) comparing children’s neurocognitive development between pre-pregnancy normal weight, as reference, with overweight and obesity categories.ResultsFifteen articles were included in the systematic review, and nine of them in the meta-analysis. The pooled ES values for overweight and obese mothers were −0.02 (95% CI: −0.05 to 0.02) and −0.06 (95% CI: −0.09 to −0.03), respectively. The pooled ES for the relationship between pre-gestational excess weight (overweight and obesity) and children’s neurocognitive development was −0.04 (95% CI: −0.06 to −0.02).ConclusionsPre-pregnancy obesity might have negative consequences on the neurocognitive development of offspring.
      PubDate: 2017-07-13
  • Survival analysis of the association between antenatal care attendance and
           neonatal mortality in 57 low- and middle-income countries
    • Authors: Doku D; Neupane S.
      Abstract: BackgroundNeonatal mortality is unacceptably high in most low- and middle-income countries (LMICs). In these countries, where access to emergency obstetric services is limited, antenatal care (ANC) utilization offers improved maternal health and birth outcomes. However, evidence for this is scanty and mixed. We explored the association between attendance for ANC and survival of neonates in 57 LMICs.MethodsEmploying standardized protocols to ensure comparison across countries, we used nationally representative cross-sectional data from 57 LMICs (N = 464 728) to investigate the association between ANC visits and neonatal mortality. Cox proportional hazards multivariable regression models and meta-regression analysis were used to analyse pooled data from the countries. Kaplan-Meier survival curves were used to describe the patterns of neonatal survival in each region.ResultsAfter adjusting for potential confounding factors, we found 55% lower risk of neonatal mortality [hazard ratio (HR) 0.45, 95% confidence interval (CI) 0.42–0.48] among women who met both WHO recommendations for ANC (first visit within the first trimester and at least four visits during pregnancy) in pooled analysis. Furthermore, meta-analysis of country-level risk shows 32% lower risk of neonatal mortality (HR 0.68, 95% CI 0.61–0.75) among those who met at least one WHO recommendation. In addition, ANC attendance was associated with lower neonatal mortality in all the regions except in the Middle East and North Africa.ConclusionsANC attendance is protective against neonatal mortality in the LMICs studied, although differences exist across countries and regions. Increasing ANC visits, along with other known effective interventions, can improve neonatal survival in these countries.
      PubDate: 2017-07-13
  • Cohort Profile: 2001 Cohort of the Longitudinal Survey of Newborns in the
           21st Century
    • Authors: Fuse K; Nishi N, Ikeda N.
      PubDate: 2017-07-04
  • Cohort Profile: Longitudinal study of preterm infants in the Pays de la
           Loire region of France (LIFT cohort)
    • Authors: Hanf M; Nusinovici S, Rouger V, et al.
      PubDate: 2017-07-03
  • Anthropometric and cardiometabolic risk factors in parents and child
           obesity in Segamat, Malaysia
    • Authors: Partap U; Young E, Allotey P, et al.
      Abstract: BackgroundThere is little evidence regarding risk factors for child obesity in Asian populations, including the role of parental anthropometric and cardiometabolic risk factors. We examined the relation between parental risk factors and child obesity in a Malaysian population.MethodsWe used data from health and demographic surveillance conducted by the South East Asia Community Observatory in Segamat, Malaysia. Analyses included 9207 individuals (4806 children, 2570 mothers and 1831 fathers). Child obesity was defined based on the World Health Organization 2007 reference. We assessed the relation between parental anthropometric (overweight, obesity and central obesity) and cardiometabolic (systolic hypertension, diastolic hypertension and hyperglycaemia) risk factors and child obesity, using mixed effects Poisson regression models with robust standard errors.ResultsWe found a high burden of overweight and obesity among children in this population (30% overweight or obese). Children of one or more obese parents had a 2-fold greater risk of being obese compared with children of non-obese parents. Sequential adjustment for parental and child characteristics did not materially affect estimates (fully adjusted relative risk for obesity in both parents: 2.39, 95% confidence interval: 1.82, 3.10, P < 0.001; P for trend < 0.001). These associations were not modified by parental or child sex. We found no consistent evidence for associations between parental cardiometabolic risk factors and child obesity.ConclusionsParental obesity was strongly associated with child obesity in this population. Further exploration of the behavioural and environmental drivers of these associations may help inform strategies addressing child obesity in Asia.
      PubDate: 2017-06-29
  • Preeclampsia mediates the association between shorter height and increased
           risk of preterm delivery
    • Authors: Morisaki N; Ogawa K, Urayama K, et al.
      Abstract: BackgroundMaternal short stature has been observed to increase the risk of preterm birth; however, the aetiology behind this phenomenon is unknown. We investigated whether preeclampsia, an obstetric complication that often leads to preterm delivery and is reported to have an inverse association with women’s height, mediates this association.MethodsWe studied 218 412 women with no underlying diseases before pregnancy, who delivered singletons from 2005 to 2011 and were included in the Japan Society of Obstetrics and Gynecology perinatal database, which is a national multi-centre-based delivery database among tertiary hospitals. We assessed the risk of preterm delivery in relation to height using multivariate analysis, and how the association was mediated by risk of preeclampsia using mediation analysis.ResultsEach 5-cm decrement in height was associated with significantly higher risk of preterm delivery [relative risk 1.20; 95% confidence interval (CI): 1.13, 1.27] and shorter gestational age (−0.30; 95% CI: −0.44, −0.16 weeks). Mediation analysis showed that the effect of shorter height on increased risk of preterm delivery, due to an indirect effect mediated through increased risk of preeclampsia, was substantial for shorter gestational age (48%), as well as risk of preterm delivery (28%). When examining the three subtypes of preterm delivery separately, mediated effect was largest for provider-initiated preterm delivery without premature rupture of membranes (PROM) (34%), compared with spontaneous preterm delivery without PROM (17%) or preterm delivery with PROM (0%).ConclusionsPreeclampsia partially mediates the association between maternal short stature and preterm delivery.
      PubDate: 2017-06-29
  • Community characteristics and regional variations in sepsis
    • Authors: Xavier Moore J; Donnelly J, Griffin R, et al.
      Abstract: BackgroundSepsis may contribute to more than 200 000 annual deaths in the USA. Little is known about the regional patterns of sepsis mortality and the community characteristics that explain this relationship. We aimed to determine the influence of community characteristics upon regional variations in sepsis incidence and case fatality.MethodsWe performed a retrospective analysis of data from the REasons for Geographic and Racial Differences in Stroke (REGARDS) cohort. Using US sepsis mortality data, we used two strategies for defining geographic regions: (i) Sepsis ‘Belt’ vs Non-Belt and (ii) Sepsis ‘Cluster’ vs Non-Cluster. We determined sepsis incidence and case fatality among REGARDS participants in each region, adjusting for participant characteristics. We examined the mediating effect of community characteristics upon regional variations in sepsis incidence and case fatality.ResultsAmong 29 680 participants, 16 493 (55.6%) resided in the Sepsis Belt and 2958 (10.0%) resided in a Sepsis Cluster. Sepsis incidence was higher for Sepsis Belt than Non-Belt participants [adjusted hazard ratio (HR) = 1.14; 95% confidence interval (CI) = 1.02–1.24] and higher for Sepsis Cluster than Non-Cluster participants (adjusted HR = 1.18; 95% CI = 1.01–1.39). Sepsis case fatality was similar between Sepsis Belt and Non-Belt participants, as well as between Cluster and Non-Cluster participants. Community poverty mediated the regional differences in sepsis incidence.ConclusionsRegional variations in sepsis incidence may be partly explained by community poverty. Other community characteristics do not explain regional variations in sepsis incidence or case fatality.
      PubDate: 2017-06-27
  • Cohort Profile: The Mother-Child Cohort in Crete, Greece (Rhea Study)
    • Authors: Chatzi L; Leventakou V, Vafeiadi M, et al.
      PubDate: 2017-06-21
  • The role of early life growth development, the FTO gene and exclusive
           breastfeeding on child BMI trajectories
    • Authors: Wu Y; Lye S, Briollais L.
      Abstract: BackgroundRecent studies have implicated the FTO gene in child and adult obesity. A longer duration of exclusive breastfeeding (EXBF) has been shown to reduce body mass index (BMI) and the risk of being overweight in the general population and among FTO gene carriers. However, it remains unclear whether the preventive effect of EXBF could be explained by its impact on early life growth development, e.g. ages at adiposity peak (AP) and adiposity rebound (AR) and BMI velocities in the first years of life, which are major determinants of overweight and obesity later in life.MethodsWe studied 5590 children from the British Avon Longitudinal Study of Parents and Children (ALSPAC) cohort and modelled their longitudinal BMI profiles with mixed effects models from birth to 16 years of age, as well as their ages at AP, AR and BMI velocities in relation to the FTO gene variant and EXBF.ResultsA longer duration of EXBF (i.e. at least 5 months) has substantial impact on BMI growth trajectories among children carrying the FTO adverse variant by modulating the age at AP, age at AR and BMI velocities. EXBF acts antagonistically to the FTO rs9939609 risk allele and by the age of 15, the predicted reduction in BMI after 5 months of EXBF is 0.56 kg/m2 [95% confidence interval (CI) 0.11–1.01; P = 0.003] and 1.14 kg/m2 (95% CI 0.67–1.62; P < 0.0001) in boys and girls, respectively.ConclusionsEXBF influences early life growth development and thus plays a critical role in preventing the risks of overweight and obesity even when those are exacerbated by genetic factors.
      PubDate: 2017-06-20
  • Associations of obesity and lifestyle with the risk and mortality of
           bloodstream infection in a general population: a 15-year follow-up of
           64 027 individuals in the HUNT Study
    • Authors: Paulsen J; Askim Å, Mohus R, et al.
      Abstract: BackgroundBloodstream infections (BSI) cause considerable morbidity and mortality, and primary prevention should be a priority. Lifestyle factors are of particular interest since they represent a modifiable target.MethodsWe conducted a prospective cohort study among participants in the population-based Norwegian HUNT2 Survey, where 64 027 participants were followed from 1995–97 through 2011 by linkage to prospectively recorded information on BSI at local and regional hospitals. The exposures were: baseline body mass index (BMI) measurements; and self-reported smoking habits, leisure time physical activity and alcohol intake. The outcomes were hazard ratios (HR) of BSI and BSI mortality.ResultsDuring 810 453 person-years and median follow-up of 14.8 years, 1844 (2.9%) participants experienced at least one BSI and 396 (0.62%) died from BSI. Compared with normal weight participants (BMI 18.5–24.9 kg/m2), the age- and sex-adjusted risk of a first-time BSI was 31% [95% confidence interval (CI) 14–51%] higher at BMI 30.0–34.9 kg/m2, 87% (95% CI 50–135%) higher at BMI 35.0–39.9 kg/m2 and 210% (95% CI 117–341%) higher at BMI ≥ 40.0 kg/m2. The risk of BSI mortality was similarly increased. Compared with never-smokers, current smokers had 51% (95% CI 34–70%) and 75% (95% CI 34–129%) higher risks of BSI and BSI mortality, respectively. Physically inactive participants had 71% (95% CI 42–107%) and 108% (95% CI 37–216%) higher risks of BSI and BSI mortality, respectively, compared with the most physically active.ConclusionsObesity, smoking and physical inactivity carry increased risk of BSI and BSI mortality.
      PubDate: 2017-06-15
  • Behavioural, not biological, factors drive the HCV epidemic among
           HIV-positive MSM: HCV and HIV modelling analysis including HCV
           treatment-as-prevention impact
    • Authors: MacGregor L; Martin N, Mukandavire C, et al.
      Abstract: BackgroundUncertainty surrounds why hepatitis C virus (HCV) is concentrated among HIV-positive men who have sex with men (MSM). We used mathematical modelling to explore reasons for these infection patterns, and implications for HCV treatment-as-prevention.MethodsUsing a joint MSM HIV/HCV transmission model parameterized with UK behavioural data, we considered how biological (heightened HCV infectivity and reduced spontaneous clearance among HIV-positive MSM) and/or behavioural factors (preferential sexual mixing by HIV status and risk heterogeneity) could concentrate HCV infection in HIV-positive MSM as commonly observed (5-20 times the HCV prevalence in HIV-negative MSM; defined as the HCV ratio). We explored how HCV treatment-as-prevention impact varies under differing HCV ratios.ResultsBiological factors produced low HCV ratios (< 3), not explaining the skewed epidemic. However, combining preferential mixing by HIV status with sexual risk behaviour heterogeneity produced high HCV ratios (> 10) that were highly sensitive to both factors. Irrespective of the HCV ratio or behavioural/biological factors, HCV treatment of HIV-diagnosed MSM markedly reduced the HCV prevalence among HIV-positive MSM, but less impact was achieved among all MSM for lower HCV ratios.ConclusionsSexual behaviour patterns likely drive observed HCV infection patterns among HIV-positive MSM. Changes in these patterns could disseminate HCV amongst HIV-negative MSM, limiting the impact of targeting HCV treatment to HIV-diagnosed MSM.
      PubDate: 2017-06-12
  • Does unmeasured confounding influence associations between the retail food
           environment and body mass index over time' The Coronary Artery Risk
           Development in Young Adults (CARDIA) study
    • Authors: Rummo P; Guilkey D, Ng S, et al.
      Abstract: BackgroundFindings in the observational retail food environment and obesity literature are inconsistent, potentially due to a lack of adjustment for residual confounding.MethodsUsing data from the CARDIA study (n = 12 174 person-observations; 6 examinations; 1985–2011) across four US cities (Birmingham, AL; Chicago, IL; Minneapolis, MN; Oakland, CA), we used instrumental-variables (IV) regression to obtain causal estimates of the longitudinal associations between the percentage of neighbourhood food stores or restaurants (per total food outlets within 1 km network distance of respondent residence) with body mass index (BMI), adjusting for individual-level socio-demographics, health behaviours, city, year, total food outlets and market-level prices. To determine the presence and extent of bias, we compared the magnitude and direction of results with ordinary least squares (OLS) and random effects (RE) regression, which do not control for residual confounding, and with fixed effects (FE) regression, which does not control for time-varying residual confounding.ResultsRelative to neighbourhood supermarkets (which tend to be larger and have healthier options than grocery stores), a higher percentage of grocery stores [mean = 53.4%; standard deviation (SD) = 31.8%] was positively associated with BMI [β = 0.05; 95% confidence interval (CI) = 0.01, 0.10] using IV regression. However, associations were negligible or null using OLS (β = −0.001; 95% CI = −0.01, 0.01), RE (β = −0.003; 95% CI = −0.01, 0.0001) and FE (β = −0.003; 95% CI = −0.01, 0.0002) regression. Neighbourhood convenience stores and fast-food restaurants were not associated with BMI in any model.ConclusionsLongitudinal associations between neighbourhood food outlets and BMI were greater in magnitude using a causal model, suggesting that weak findings in the literature may be due to residual confounding.
      PubDate: 2017-06-06
  • Maternal consumption of artificially sweetened beverages during pregnancy,
           and offspring growth through 7 years of age: a prospective cohort study
    • Authors: Zhu Y; Olsen S, Mendola P, et al.
      Abstract: BackgroundArtificial sweeteners are widely replacing caloric sweeteners. Data on long-term impact of artificially sweetened beverage (ASB) consumption during pregnancy on offspring obesity risk are lacking. We prospectively investigated intake of ASBs and sugar-sweetened beverages (SSBs) during pregnancy in relation to offspring growth through age 7 years among high-risk children born to women with gestational diabetes.MethodsIn a prospective study of 918 mother-singleton child dyads from the Danish National Birth Cohort, maternal dietary intake was assessed by a food frequency questionnaire during pregnancy. Offspring body mass index z-scores (BMIZ) and overweight/obesity status were derived using weight and length/height at birth, 5 and 12 months and 7 years. Linear regression and Poisson regression with robust standard errors were used, adjusting for major risk factors.ResultsApproximately half of women reported consuming ASBs during pregnancy and 9% consumed daily. Compared to never consumption, daily ASB intake during pregnancy was positively associated with offspring large-for-gestational age [adjusted relative risk (aRR) 1.57; 95% CI: 1.05, 2.35 at birth], BMIZ (adjusted β 0.59; 95% CI: 0.23, 0.96) and overweight/obesity (aRR 1.93; 95% CI; 1.24, 3.01) at 7 years. Per-serving-per-day substitution of ASBs with water during pregnancy was related to a lower overweight/obesity risk at 7 years (aRR 0.83; 95% CI: 0.76, 0.91), whereas SSB substitution with ASBs was not related to a lower risk (aRR 1.14; 95% CI: 1.00, 1.31).ConclusionsOur findings illustrated positive associations between intrauterine exposure to ASBs and birth size and risk of overweight/obesity at 7 years. Data with longer follow-up are warranted.
      PubDate: 2017-06-06
  • Trends in obesity and diabetes across Africa from 1980 to 2014: an
           analysis of pooled population-based studies
    • Authors: .
      Abstract: BackgroundThe 2016 Dar Es Salaam Call to Action on Diabetes and Other non-communicable diseases (NCDs) advocates national multi-sectoral NCD strategies and action plans based on available data and information from countries of sub-Saharan Africa and beyond. We estimated trends from 1980 to 2014 in age-standardized mean body mass index (BMI) and diabetes prevalence in these countries, in order to assess the co-progression and assist policy formulation.MethodsWe pooled data from African and worldwide population-based studies which measured height, weight and biomarkers to assess diabetes status in adults aged ≥ 18 years. A Bayesian hierarchical model was used to estimate trends by sex for 200 countries and territories including 53 countries across five African regions (central, eastern, northern, southern and western), in mean BMI and diabetes prevalence (defined as either fasting plasma glucose of ≥ 7.0 mmol/l, history of diabetes diagnosis, or use of insulin or oral glucose control agents).ResultsAfrican data came from 245 population-based surveys (1.2 million participants) for BMI and 76 surveys (182 000 participants) for diabetes prevalence estimates. Countries with the highest number of data sources for BMI were South Africa (n = 17), Nigeria (n = 15) and Egypt (n = 13); and for diabetes estimates, Tanzania (n = 8), Tunisia (n = 7), and Cameroon, Egypt and South Africa (all n = 6). The age-standardized mean BMI increased from 21.0 kg/m2 (95% credible interval: 20.3–21.7) to 23.0 kg/m2 (22.7–23.3) in men, and from 21.9 kg/m2 (21.3–22.5) to 24.9 kg/m2 (24.6–25.1) in women. The age-standardized prevalence of diabetes increased from 3.4% (1.5–6.3) to 8.5% (6.5–10.8) in men, and from 4.1% (2.0–7.5) to 8.9% (6.9–11.2) in women. Estimates in northern and southern regions were mostly higher than the global average; those in central, eastern and western regions were lower than global averages. A positive association (correlation coefficient ≃ 0.9) was observed between mean BMI and diabetes prevalence in both sexes in 1980 and 2014.ConclusionsThese estimates, based on limited data sources, confirm the rapidly increasing burden of diabetes in Africa. This rise is being driven, at least in part, by increasing adiposity, with regional variations in observed trends. African countries’ efforts to prevent and control diabetes and obesity should integrate the setting up of reliable monitoring systems, consistent with the World Health Organization’s Global Monitoring System Framework.
      PubDate: 2017-06-04
  • Changes in blood DNA methylation and incomplete adjustment for blood cell
    • Authors: Karmaus W; Chen S.
      Abstract: Addressing change and stability over time, the two poles in DNA methylation (DNA-m) patterns, are new areas of interest in epigenetic research. On the one pole, research has focused on stability and consistency.1–3 For instance, in a British cohort of 92 participants, 35-84 years of age, the methylation of cytosine-phosphate-guanine (CpG) dinucleotides sequences was measured twice, 6 years apart.3 The authors found 17% of the 353 633 CpGs were stable after exclusion of CpGs that were influenced by genetic variants [single nucleotide polymorphisms (SNPs)] in their DNA-m measurement probes. On the other hand, a recent article published in the International Journal of Epidemiology focused on changes of DNA methylation. Results from this Danish study by Tan et al. identified statistically significant changes in CpG methylation in 43 paired measurements 10 years apart (age range at first measurement: 73-82 years).4 Compared with the British study, the investigators removed a smaller number of CpGs affected by probe SNPs, resulting in a total of 424 706 CpGs that were analysed. Their results showed that 0.054% (2284 of 424 706) CpGs changed significantly.
      PubDate: 2017-06-03
  • Handling blood cell composition in epigenetic studies on ageing
    • Authors: Tan Q; Heijmans B, Hjelmborg J, et al.
      Abstract: As an easily accessible tissue, whole blood has been widely used as a target tissue in epigenetic studies on ageing and diseases. The price to pay for the convenience in biopsy is cell type heterogeneity, an issue that can be alleviated by adjusting for estimated cell type proportions.1 In the case of ageing studies, Karmaus and Chen proposed to extend the adjustment to further include time or age-dependent effect of each cell type. This assumes that the age trajectory of epigenetic alteration differs in different cell types. Although this gives more freedom in fitting the data, the practice means that we need to adjust for more than 10 parameters, which would undermine statistical power in small-scale studies. Moreover, the cell type proportions that cost a large number of parameters are not real observations but model estimates involving considerable degrees of uncertainty. Gervin et al.2 recently compared the cell type estimates1 with matched real cell counts, and reported moderate to high correlations between the two depending on cell type, with correlation estimates between 0.51 and 0.57 in three cell types. Similar levels of estimates were also reported in an earlier study.3 Too much parameterization on such uncertain variables could inevitably lead to biased or insignificant results in small-scale studies.
      PubDate: 2017-06-03
  • Adherence to a healthy lifestyle and the risk of type 2 diabetes in
           Chinese adults
    • Authors: Lv J; Yu C, Guo Y, et al.
      Abstract: BackgroundSimultaneously adhering to multiple healthy lifestyle factors has been related to up to 90% reduction in type 2 diabetes (T2DM) incidence in White populations; however, little is known about whether such protective effects persist in other non-White populations.MethodsWe examined the associations of six lifestyle factors with T2DM in the China Kadoorie Biobank of 461 211 participants aged 30–79 years without diabetes, cardiovascular diseases or cancer at baseline. We defined low-risk lifestyle factors as non-smoking or having stopped for reasons other than illness; alcohol consumption of <30 g/day; upper quarter of the physical activity level; diet rich in vegetables and fruits, low in red meat and with some degree of replacement of rice with wheat; body mass index (BMI) of 18.5–23.9 kg/m2; and waist-to-hip ratio (WHR) <0.90 (men)/<0.85 (women).ResultsDuring a median of 7.2 years of follow-up, we identified 8784 incident T2DM. In multivariable-adjusted analyses, two important risk factors for developing T2DM were higher BMI and WHR. Compared with participants without any low-risk factors, the hazard ratio [95% confidence interval (CI)] for those with at least three low-risk factors was 0.20 (0.19, 0.22). Approximately 72.6% (64.2%, 79.3%) of the incident diabetes were attributable to the combination of BMI, WHR, diet and physical activity. The population attributable risk percentage (PAR%) of diabetes appeared to be similar for men and women, and higher among urban, older and obese participants.ConclusionsOur findings indicate that adherence to a healthy lifestyle may substantially lower the burden of T2DM in the Chinese population.
      PubDate: 2017-06-03
  • Power calculator for instrumental variable analysis in
    • Authors: Walker V; Davies N, Windmeijer F, et al.
      Abstract: BackgroundInstrumental variable analysis, for example with physicians’ prescribing preferences as an instrument for medications issued in primary care, is an increasingly popular method in the field of pharmacoepidemiology. Existing power calculators for studies using instrumental variable analysis, such as Mendelian randomization power calculators, do not allow for the structure of research questions in this field. This is because the analysis in pharmacoepidemiology will typically have stronger instruments and detect larger causal effects than in other fields. Consequently, there is a need for dedicated power calculators for pharmacoepidemiological research.Methods and ResultsThe formula for calculating the power of a study using instrumental variable analysis in the context of pharmacoepidemiology is derived before being validated by a simulation study. The formula is applicable for studies using a single binary instrument to analyse the causal effect of a binary exposure on a continuous outcome. An online calculator, as well as packages in both R and Stata, are provided for the implementation of the formula by others.ConclusionsThe statistical power of instrumental variable analysis in pharmacoepidemiological studies to detect a clinically meaningful treatment effect is an important consideration. Research questions in this field have distinct structures that must be accounted for when calculating power. The formula presented differs from existing instrumental variable power formulae due to its parametrization, which is designed specifically for ease of use by pharmacoepidemiologists.
      PubDate: 2017-05-30
  • Early cannabis initiation and educational attainment: is the association
           causal' Data from the French TEMPO study
    • Authors: Melchior M; Bolze C, Fombonne E, et al.
      Abstract: BackgroundAdolescent cannabis use has been reported to predict later educational attainment; however, results of past studies may be confounded by inappropriate control for factors that make some youths more likely to use cannabis precociously than others. We aimed to test the possibility of a causal relationship between early cannabis initiation and later academic achievement.MethodsAnalyses are based on data collected among TEMPO cohort study participants (France, 2009, n = 1103, 22–35 years). Participants were previously assessed in childhood (1991) and adolescence (1999); additionally, their parents had taken part in a longitudinal epidemiological cohort study (GAZEL). Early cannabis initiation was defined as use at age 16 or earlier. Educational attainment was defined as the completion of a high-school degree (‘Baccalauréat’). Early (up to and including age 16 years) and late (after age 16 years) cannabis-use initiators were compared with non-users using logistic regression models controlled for inverse probability weights (IPWs) of exposure calculated based on participants’ socio-demographic, juvenile and parental characteristics.ResultsIn age- and sex-adjusted analyses, early cannabis initiators were more likely than non-users to have low educational attainment [odds ratio (OR): 1.77, 95% confidence interval (CI) 1.22–2.55]. In IPWs-controlled analyses, this association somewhat decreased (OR: 1.64, 95% CI 1.13–2.40). Late cannabis initiators did not have lower educational attainment than non-users. Early cannabis use and educational attainment appeared more strongly associated in young women than in young men.ConclusionsEarly cannabis can cause low educational attainment. Youths who initiate cannabis use early require attention from addiction and education specialists to reduce their odds of poor long-term outcomes.
      PubDate: 2017-05-18
  • Data Resource Profile: Seeding Success: a cross-sectoral data resource for
           early childhood health and development research in Australian Aboriginal
           and non-Aboriginal children
    • Authors: Falster K; Jorgensen M, Hanly M, et al.
      PubDate: 2017-05-11
  • Cohort Profile: The Tracking Opportunities and Problems Study
           (TOPP)–study of Norwegian children and their parents followed from
           infancy to early adulthood
    • Authors: Nilsen W; Kjeldsen A, Karevold E, et al.
      PubDate: 2017-05-11
  • Mendelian randomization for investigating causal roles of biomarkers in
    • Authors: Abbasi A.
      PubDate: 2017-05-02
  • Lessons from Mendelian randomization studies on liver biomarkers: response
           to Abbasi
    • Authors: Noordam R; Smit R, Postmus I, et al.
      Abstract: Mendelian randomization (MR) analyses, in which a genetic instrumental variable is used to infer causality between a putative causal factor and outcome, are becoming increasingly popular in scientific literature. In particular, recent methodological advances have led to a surge in popularity of two-sample summary data MR analyses, which use summary-level data [e.g. beta and standard error of the association of one or more genetic instrument(s) with exposure and/or outcome] from (published) genome-wide association studies. This expanding methodological field, and its accompanying diversity in underlying assumptions, requires researchers to be transparent in their presentation of methods and interpretation of results. We therefore fully agree with Abbasi that objective assessment tools are needed to measure the quality of conducted MR studies.1
      PubDate: 2017-05-02
  • Fresh fruit consumption and all-cause and cause-specific mortality:
           findings from the China Kadoorie Biobank
    • Authors: Du H; Li L, Bennett D, et al.
      Abstract: BackgroundHigher fruit consumption is associated with lower risk of cardiovascular disease (CVD). Substantial uncertainties remain, however, about the associations of fruit consumption with all-cause mortality and mortality from subtypes of CVD and major non-vascular diseases, especially in China.MethodsIn 2004–08, the nationwide China Kadoorie Biobank Study recruited > 0.5 million adults aged 30–79 years from 10 diverse localities in China. Fresh fruit consumption was estimated using an interviewer-administered electronic questionnaire, and mortality data were collected from death registries. Among the 462 342 participants who were free of major chronic diseases at baseline, 17 894 deaths were recorded during ∼ 7 years of follow-up. Cox regression yielded adjusted rate ratios (RRs) for all-cause and cause-specific mortality associated with fruit consumption.ResultsAt baseline, 28% of participants reported consuming fruit ≥ 4 days/week (regular consumers) and 6% reported never/rarely consuming fruit (non-consumers). Compared with non-consumers, regular consumers had 27% [RR = 0.73, 95% confidence interval (CI) 0.70–0.76] lower all-cause mortality, 34% lower CVD mortality (n = 6166; RR = 0.66, 0.61–0.71), 17% lower cancer mortality (n = 6796; RR = 0.83, 0.78–0.89) and 42% lower mortality from chronic obstructive pulmonary disease (COPD) (n = 1119; RR = 0.58, 0.47–0.71). For each of the above, there was an approximately log-linear dose-response relationship with amount consumed. For mortality from site-specific cancers, fruit consumption was inversely associated with digestive tract cancer (n = 2265; RR = 0.72, 0.64–0.81), particularly oesophageal cancer (n = 801; RR = 0.65, 0.50–0.83), but not with cancer of lung or liver.ConclusionsAmong Chinese adults, higher fresh fruit consumption was associated with significantly lower mortality from several major vascular and non-vascular diseases. Given the current low population level of fruit consumption, substantial health benefits could be gained from increased fruit consumption in China.
      PubDate: 2017-04-24
  • Maternal alcohol use during pregnancy and offspring attention-deficit
           hyperactivity disorder (ADHD): a prospective sibling control study
    • Authors: Eilertsen E; Gjerde L, Reichborn-Kjennerud T, et al.
      Abstract: BackgroundMaternal alcohol use during pregnancy has repeatedly been associated with development of attention-deficit hyperactivity disorder (ADHD) in the offspring. It is, however not known whether this reflects a direct casual intra-uterine effect or a non-causal relationship due to confounding. We used three different approaches to control for measured and unmeasured confounding: statistical adjustment for covariates, negative control comparison against maternal pre-pregnancy alcohol use, and comparison among differentially exposed siblings.MethodsThe sample comprised 114 247 children (34 283 siblings) from 94 907 mothers, recruited to the Norwegian Mother and Child Birth Cohort Study between 1999 and 2008. Self-reported measurements of alcohol use were obtained in week 30 during the pregnancy. Mothers rated offspring ADHD symptoms at 5 years on two measures. Clinical ADHD diagnoses were obtained from the Norwegian Patient Registry.ResultsWe found an overall positive association between maternal alcohol use during pregnancy and offspring ADHD symptoms, which was only marginally attenuated after inclusion of measured covariates. Both the negative control and the sibling comparison analysis further attenuated the estimated association, but it remained greater than zero [β = 0.017, 95% confidence interval (CI) = 0.005–0.030). No association was found between maternal alcohol use during pregnancy and offspring ADHD diagnosis.ConclusionsFor offspring ADHD symptoms we found a weak, but possibly causal association with maternal alcohol use during pregnancy, but no such effect was observed for clinical ADHD diagnosis.
      PubDate: 2017-04-24
  • Risk of heterosexual HIV transmission attributable to sexually transmitted
           infections and non-specific genital inflammation in Zambian discordant
           couples, 1994–2012
    • Authors: Wall K; Kilembe W, Vwalika B, et al.
      Abstract: BackgroundStudies have demonstrated the role of ulcerative and non-ulcerative sexually transmitted infections (STI) in HIV transmission/acquisition risk; less is understood about the role of non-specific inflammatory genital abnormalities.MethodsHIV-discordant heterosexual Zambian couples were enrolled into longitudinal follow-up (1994–2012). Multivariable models estimated the effect of genital ulcers and inflammation in both partners on time-to-HIV transmission within the couple. Population-attributable fractions (PAFs) were calculated.ResultsA total of 207 linked infections in women occurred over 2756 couple-years (7.5/100 CY) and 171 in men over 3216 CY (5.3/100 CY). Incident HIV among women was associated with a woman’s non-STI genital inflammation (adjusted hazard ratio (aHR) = 1.55; PAF = 8%), bilateral inguinal adenopathy (BIA; aHR = 2.33; PAF = 8%), genital ulceration (aHR = 2.08; PAF = 7%) and the man’s STI genital inflammation (aHR = 3.33; PAF = 5%), BIA (aHR = 3.35; PAF = 33%) and genital ulceration (aHR = 1.49; PAF = 9%). Infection among men was associated with a man’s BIA (aHR = 4.11; PAF = 22%) and genital ulceration (aHR = 3.44; PAF = 15%) as well as with the woman’s non-STI genital inflammation (aHR = 1.92; PAF = 13%) and BIA (aHR = 2.76; PAF = 14%). In HIV-M+F- couples, the man being uncircumcised. with foreskin smegma. was associated with the woman’s seroconversion (aHR = 3.16) relative to being circumcised. In F+M- couples, uncircumcised men with BIA had an increased hazard of seroconversion (aHR = 13.03 with smegma and 4.95 without) relative to being circumcised. Self-reporting of symptoms was low for ulcerative and non-ulcerative STIs.ConclusionsOur findings confirm the role of STIs and highlight the contribution of non-specific genital inflammation to both male-to-female and female-to-male HIV transmission/acquisition risk. Studies are needed to characterize pathogenesis of non-specific inflammation including inguinal adenopathy. A better understanding of genital practices could inform interventions.
      PubDate: 2017-04-11
  • Prospective associations between diet quality and body mass index in
           disadvantaged women: the Resilience for Eating and Activity Despite
           Inequality (READI) study
    • Authors: Olstad D; Lamb K, Thornton L, et al.
      Abstract: BackgroundDietary patterns that align with recommended guidelines appear to minimize long-term weight gain in the general population. However, prospective associations between diet quality and weight change in disadvantaged adults have not been examined. This study examined associations between concurrent change in diet quality and body mass index (BMI) over 5 years among women living in socioeconomically disadvantaged neighbourhoods.MethodsDietary intake and BMI were self-reported among 1242 women living in disadvantaged neighbourhoods in Victoria, Australia, at three time points from 2007/08 to 2012/13. Diet quality was evaluated using the Australian Dietary Guideline Index (DGI). Associations between concurrent change in diet quality and BMI were assessed over the three time points using fixed effects and mixed models. Models were adjusted for age, smoking, menopausal status, education, marital status, number of births, urban/rural location and physical activity.ResultsAverage BMI increased by 0.14 kg/m2 per year increase in age in the fixed effects model, and by 0.13 kg/m2 in the mixed model (P < 0.0001). BMI decreased by 0.014 kg/m2 for a woman of average age with each unit increase in DGI score in the fixed effects model (p < 0.0001), and by 0.012 kg/m2 in the mixed model (P = 0.001). The rate of change in BMI with age was greater for those with a lower DGI score than for those with a higher score (P < 0.10).ConclusionsPositive change in diet quality was associated with reduced BMI gain among disadvantaged women. Supporting disadvantaged women to adhere to population-level dietary recommendations may assist them with long-term weight management.
      PubDate: 2017-04-07
  • Corrigendum Cohort Profile: The ENVIRonmental influence ON early AGEing
           (ENVIRONAGE): a birth cohort study
    • Authors: Janssen B; Madhloum N, Gyselaers W, et al.
      Abstract: doi: 10.1093/ije/dyw269 First published online International Journal of Epidemiology, 15 January 2017
      PubDate: 2017-03-22
  • Association between birthweight and later body mass index: an
           individual-based pooled analysis of 27 twin cohorts participating in the
           CODATwins project
    • Authors: Jelenkovic A; Yokoyama Y, Sund R, et al.
      Abstract: BackgroundThere is evidence that birthweight is positively associated with body mass index (BMI) in later life, but it remains unclear whether this is explained by genetic factors or the intrauterine environment. We analysed the association between birthweight and BMI from infancy to adulthood within twin pairs, which provides insights into the role of genetic and environmental individual-specific factors.MethodsThis study is based on the data from 27 twin cohorts in 17 countries. The pooled data included 78 642 twin individuals (20 635 monozygotic and 18 686 same-sex dizygotic twin pairs) with information on birthweight and a total of 214 930 BMI measurements at ages ranging from 1 to 49 years. The association between birthweight and BMI was analysed at both the individual and within-pair levels using linear regression analyses.ResultsAt the individual level, a 1-kg increase in birthweight was linearly associated with up to 0.9 kg/m2 higher BMI (P < 0.001). Within twin pairs, regression coefficients were generally greater (up to 1.2 kg/m2 per kg birthweight, P < 0.001) than those from the individual-level analyses. Intra-pair associations between birthweight and later BMI were similar in both zygosity groups and sexes and were lower in adulthood.ConclusionsThese findings indicate that environmental factors unique to each individual have an important role in the positive association between birthweight and later BMI, at least until young adulthood.
      PubDate: 2017-03-19
  • Gamma-glutamyltransferase levels, prediabetes and type 2 diabetes: a
           Mendelian randomization study
    • Authors: Nano J; Muka T, Ligthart S, et al.
      Abstract: BackgroundHigh levels of serum gamma-glutamyltransferase (GGT) are associated with increased risk of prediabetes and type 2 diabetes in observational studies. It is unclear whether this relationship is causal, arises from residual confounding or is a consequence of reverse causation.MethodsWe used data from a prospective population-based cohort study, compromising 8611 individuals without diabetes at baseline. Cox proportional hazard models were used to study the association between serum GGT levels and incident prediabetes and diabetes. A Mendelian randomization (MR) study was performed using a genetic risk score consisting of 26 GGT-related variants, based on a genome-wide association study (GWAS) on liver enzymes. Association with diabetes and glycaemic traits were investigated within the Rotterdam Study and large-scale GWAS.ResultsDuring follow-up, 1125 cases of prediabetes (mean follow-up 5.7 years) and 811 cases of type 2 diabetes (6.9 years) were ascertained. The predicted hazard ratios per standard deviation (SD) change in GGT levels in the multivariable model were 1.10 for prediabetes [95% confidence interval (CI): 1.02–1.19] and 1.19 for type 2 diabetes (95% CI: 1.10–1.30). The genetic risk score associated with increased GGT levels (beta per SD log GGT = 0.41, 95% CI: 0.35–0.47), explaining 3.5% of the observed variation in GGT. MR analysis did not provide evidence for a causal role of GGT, with a causal relative risk for prediabetes and type 2 diabetes per SD of log GGT of 0.97 (95% CI: 0.91–1.04) and 0.96 (95% CI: 0.89–1.04), respectively. Multiple instrumental analysis using genetic associations with type 2 diabetes and glycaemic traits from previous GWA studies detected no causal effect of GGT.ConclusionsMR analyses did not support a causal role of GGT on the risk of prediabetes or diabetes. The association of GGT with diabetes in observational studies is likely to be driven by reverse causation or confounding bias. As such, therapeutics targeted at lowering GGT levels are unlikely to be effective in preventing diabetes.
      PubDate: 2017-03-13
  • Cohort Profile: The Hepatitis C Virus (HCV) Research UK Clinical Database
           and Biobank
    • Authors: McLauchlan J; Innes H, Dillon J, et al.
      PubDate: 2017-02-27
  • Fish and seafood consumption during pregnancy and the risk of asthma and
           allergic rhinitis in childhood: a pooled analysis of 18 European and US
           birth cohorts
    • Authors: Stratakis N; Roumeliotaki T, Oken E, et al.
      Abstract: BackgroundIt has been suggested that prenatal exposure to n-3 long-chain fatty acids protects against asthma and other allergy-related diseases later in childhood. The extent to which fish intake in pregnancy protects against child asthma and rhinitis symptoms remains unclear. We aimed to assess whether fish and seafood consumption in pregnancy is associated with childhood wheeze, asthma and allergic rhinitis.MethodsWe pooled individual data from 60 774 mother-child pairs participating in 18 European and US birth cohort studies. Information on wheeze, asthma and allergic rhinitis prevalence was collected using validated questionnaires. The time periods of interest were: infancy (0-2 years), preschool age (3-4 years), and school age (5-8 years). We used multivariable generalized models to assess associations of fish and seafood (other than fish) consumption during pregnancy with child respiratory outcomes in cohort-specific analyses, with subsequent random-effects meta-analyses.ResultsThe median fish consumption during pregnancy ranged from 0.44 times/week in The Netherlands to 4.46 times/week in Spain. Maternal fish intake during pregnancy was not associated with offspring wheeze symptoms in any age group nor with the risk of child asthma [adjusted meta-analysis relative risk (RR) per 1-time/week = 1.01, 95% confidence interval 0.97-1.05)] and allergic rhinitis at school age (RR = 1.01, 0.99-1.03). These results were consistently found in further analyses by type of fish and seafood consumption and in sensitivity analyses.ConclusionWe found no evidence supporting a protective association of fish and seafood consumption during pregnancy with offspring symptoms of wheeze, asthma and allergic rhinitis from infancy to mid childhood.
      PubDate: 2017-02-27
  • Population-level interventions in government jurisdictions for dietary
           sodium reduction: a Cochrane Review
    • Authors: Barberio A; Sumar N, Trieu K, et al.
      Abstract: BackgroundWorldwide, excessive salt consumption is common and is a leading cause of high blood pressure. Our objectives were to assess the overall and differential impact (by social and economic indicators) of population-level interventions for dietary sodium reduction in government jurisdictions worldwide.MethodsThis is a Cochrane systematic review. We searched nine peer-reviewed databases, seven grey literature resources and contacted national programme leaders. We appraised studies using an adapted version of the Cochrane risk of bias tool. To assess impact, we computed the mean change in salt intake (g/day) from before to after intervention.ResultsFifteen initiatives met the inclusion criteria and 10 provided sufficient data for quantitative analysis of impact. Of these, five showed a mean decrease in salt intake from before to after intervention including: China, Finland (Kuopio area), France, Ireland and the UK. When the sample was constrained to the seven initiatives that were multicomponent and incorporated activities of a structural nature (e.g. procurement policy), most (4/7) showed a mean decrease in salt intake. A reduction in salt intake was more apparent among men than women. There was insufficient information to assess differential impact by other social and economic axes. Although many initiatives had methodological strengths, all scored as having a high risk of bias reflecting the observational design. Study heterogeneity was high, reflecting different contexts and initiative characteristics.ConclusionsPopulation-level dietary sodium reduction initiatives have the potential to reduce dietary salt intake, especially if they are multicomponent and incorporate intervention activities of a structural nature. It is important to consider data infrastructure to permit monitoring of these initiatives.
      PubDate: 2017-02-15
  • Cohort Profile: The All Our Babies pregnancy cohort (AOB)
    • Authors: Tough S; McDonald S, Collisson B, et al.
      PubDate: 2017-02-08
  • Cohort Profile: The transition from childhood to adolescence in European
           children–how I.Family extends the IDEFICS cohort
    • Authors: Ahrens W; Siani A, Adan R, et al.
      PubDate: 2017-01-23
  • Cohort Profile: The ENVIRonmental influence ON early AGEing (ENVIR ON
           AGE): a birth cohort study
    • Authors: Janssen B; Madhloum N, Gyselaers W, et al.
      PubDate: 2017-01-15
  • Cohort Profile: The Australian Aboriginal Birth Cohort (ABC) study
    • Authors: Sayers S; Mackerras D, Singh G.
      PubDate: 2017-01-07
  • Cohort Profile: The Western Australian Pregnancy Cohort (Raine)
           Study–Generation 2
    • Authors: Straker L; Mountain J, Jacques A, et al.
      PubDate: 2017-01-07
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