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BACKGROUND: Maternal obesity has been implicated in the origins of childhood obesity through a suboptimal environment in-utero.OBJECTIVE: We examined relationships of maternal early pregnancy body mass index (BMI), overweight/obesity, and plasma biomarkers of obesity, inflammation, insulin resistance, and placental function with measures of childhood BMI and adiposity.METHODS: BMI z-score, sum of skinfold thicknesses (SST), body fat percentage (BFP, by bioelectrical impedance), and waist, arm, and hip circumferences were measured in 1173 6-year-old children of nulliparous pregnant women in the Screening for Pregnancy Endpoints (SCOPE) study, New Zealand. Relationships of maternal early pregnancy (15 weeks' gestation) BMI and biomarkers with these childhood anthropometric measures were assessed by linear regression, with appropriate adjustment.RESULTS: 28.1% of mothers were classified as overweight and 10.1% with obesity; compared with normal weight mothers, the BFP of their children were 5.3% higher (0.16 SD [95% CI, 0.04-0.29] p = .01) and 7.8% higher (0.27 [0.08-0.47] p = .006) with comparable values for BMI z-score and arm, waist, and hip circumferences. Early pregnancy maternal BMI and plasma placental growth factor (PlGF) were associated with higher child's SST, BMI z-score, hip circumference, and BFP. None of the metabolic or inflammatory maternal biomarkers were associated with childhood obesity.CONCLUSION: In this contemporary large prospective cohort study with extensive maternal/childhood phenotyping and a high prevalence of maternal overweight/obesity, we found independent relationships of maternal early pregnancy BMI with childhood BMI and adiposity; similar associations were observed with PlGF, which may imply a role for placenta function in the developmental programming of childhood obesity risk.

BackgroundLate stillbirth, which occurs ≥28weeks' gestation, affects 1.3-8.8 per 1000 births in high-income countries. Of concern, most occur in women without established risk factors. Identification of potentially modifiable risk factors that relate to maternal behaviors remains a priority in stillbirth prevention research. This study aimed to investigate, in an international cohort, whether maternal sleep practices are related to late stillbirth.MethodsAn Internet-based case-control study of women who had a stillbirth ≥28weeks' gestation within 30days before completing the survey (n=153) and women with an ongoing third-trimester pregnancy or who had delivered a live born child within 30days (n=480). Bivariate and multivariate logistic regressions were used to determine unadjusted and adjusted odds ratios (OR and aOR, respectively) with 95% confidence intervals (95% CIs) for stillbirth.ResultsSleeping >9hours per night in the previous month was associated with stillbirth (aOR 1.75 [95% CI 1.10-2.79]), as was waking on the right side (2.27 [1.31-3.92]). Nonrestless sleep in the last month was also found to be associated with stillbirth (1.73 [1.03-2.99]), with good sleep quality in the last month approaching significance (1.64 [0.98-2.75]). On the last night of pregnancy, not waking more than one time was associated with stillbirth (2.03 [1.24-3.34]). No relationship was found with going to sleep position during pregnancy, although very few women reported settling in the supine position (2.4%).ConclusionsLong periods of undisturbed sleep are associated with late stillbirth. Physiological studies of how the neuroendocrine and autonomic system pathways are regulated during sleep in the context of late pregnancy are warranted.

Background: Phase Three of the International Study of Asthma and Allergies in Childhood (ISAAC) measured the global prevalence of symptoms of asthma in children. We undertook comprehensive analyses addressing risk factors for asthma symptoms in combination, at both the individual and the school level, to explore the potential role of reverse causation due to selective avoidance or confounding by indication. Objective: To explore the role of reverse causation in risk factors of asthma symptoms. Methods: We compared two sets of multilevel logistic regression analyses, using (a) individual level exposure data and (b) school level average exposure (ie prevalence), in two different age groups. In individual level analyses, reverse causation is a possible concern if individual level exposure statuses were changed as a result of asthma symptoms or diagnosis. School level analyses may suffer from ecologic confounding, but reverse causation is less of a concern because individual changes in exposure status as a result of asthma symptoms would only have a small effect on overall school exposure levels. Results: There were 131 924 children aged 6-7 years (2428 schools, 25 countries) with complete exposure, outcome and confounder data. The strongest associations in individual level analyses (fully adjusted) were for current paracetamol use (odds ratio = 2.06; 95% confidence interval 1.97-2.16), early life antibiotic use (1.65; 1.58-1.73) and open fire cooking (1.44; 1.26-1.65). In school level analyses, these risk factors again showed increased risks. There were 238 586 adolescents aged 13-14 years (2072 schools, 42 countries) with complete exposure, outcome and confounder data. The strongest associations in individual level analyses (fully adjusted) were for current paracetamol use (1.80; 1.75-1.86), cooking on an open fire (1.32; 1.22-1.43) and maternal tobacco use (1.23; 1.18-1.27). In school level analyses, these risk factors again showed increased risks. Conclusions & clinical relevance: These analyses strengthen the potentially causal interpretation of previously reported individual level findings, by providing evidence against reverse causation. Revisión por pares

Background: Phase Three of the International Study of Asthma and Allergies in Childhood (ISAAC) measured the global prevalence of symptoms of asthma in children. We undertook comprehensive analyses addressing risk factors for asthma symptoms in combination, at both the individual and the school level, to explore the potential role of reverse causation due to selective avoidance or confounding by indication. Objective: To explore the role of reverse causation in risk factors of asthma symptoms. Methods: We compared two sets of multilevel logistic regression analyses, using (a) individual level exposure data and (b) school level average exposure (ie prevalence), in two different age groups. In individual level analyses, reverse causation is a possible concern if individual level exposure statuses were changed as a result of asthma symptoms or diagnosis. School level analyses may suffer from ecologic confounding, but reverse causation is less of a concern because individual changes in exposure status as a result of asthma symptoms would only have a small effect on overall school exposure levels. Results: There were 131 924 children aged 6-7 years (2428 schools, 25 countries) with complete exposure, outcome and confounder data. The strongest associations in individual level analyses (fully adjusted) were for current paracetamol use (odds ratio = 2.06; 95% confidence interval 1.97-2.16), early life antibiotic use (1.65; 1.58-1.73) and open fire cooking (1.44; 1.26-1.65). In school level analyses, these risk factors again showed increased risks. There were 238 586 adolescents aged 13-14 years (2072 schools, 42 countries) with complete exposure, outcome and confounder data. The strongest associations in individual level analyses (fully adjusted) were for current paracetamol use (1.80; 1.75-1.86), cooking on an open fire (1.32; 1.22-1.43) and maternal tobacco use (1.23; 1.18-1.27). In school level analyses, these risk factors again showed increased risks. Conclusions & clinical relevance: These analyses strengthen the potentially causal interpretation of previously reported individual level findings, by providing evidence against reverse causation.

Introduction Accumulating evidence has shown an association between maternal supine going-to-sleep position and stillbirth in late pregnancy. Advising women not to go-to-sleep on their back can potentially reduce late stillbirth rate by 9%. However, the association between maternal right-sided going-to-sleep position and stillbirth is inconsistent across studies. Furthermore, individual studies are underpowered to investigate interactions between maternal going-to-sleep position and fetal vulnerability, which is potentially important for producing clear and tailored public health messages on safe going-to-sleep position. We will use individual participant data (IPD) from existing studies to assess whether right-side and supine going-to-sleep positions are independent risk factors for late stillbirth and to test the interaction between going-to-sleep position and fetal vulnerability.Methods and analysis An IPD meta-analysis approach will be used using the Cochrane Collaboration-endorsed methodology. We will identify case–control and prospective cohort studies and randomised trials which collected maternal going-to-sleep position data and pregnancy outcome data that included stillbirth. The primary outcome is stillbirth. A one stage procedure meta-analysis, stratified by study with adjustment of a priori confounders will be carried out.Ethics and dissemination The IPD meta-analysis has obtained central ethics approval from the New Zealand Health and Disability Ethics Committee, ref: NTX/06/05/054/AM06. Individual studies should also have ethical approval from relevant local ethics committees. Interpretation of the results will be discussed with consumer representatives. Results of the study will be published in peer-reviewed journals and presented at international conferences.