Maternal smoking during pregnancy and offspring overweight: is there a dose-response relationship? An individual patient data meta-analysis.

BACKGROUND/OBJECTIVES: A number of meta-analyses suggest an association between any maternal smoking in pregnancy and offspring overweight obesity. Whether there is a dose-response relationship across number of cigarettes and whether this differs by sex remains unclear. SUBJECT/METHODS: Studies reporting number of cigarettes smoked during pregnancy and offspring BMI published up to May 2015 were searched. An individual patient data meta-analysis of association between the number of cigarettes smoked during pregnancy and offspring overweight (defined according to the International Obesity Task Force reference) was computed using a generalized additive mixed model with non-linear effects and adjustment for confounders (maternal weight status, breastfeeding, and maternal education) and stratification for sex. RESULTS: Of 26 identified studies, 16 authors provided data on a total of 238,340 mother-child-pairs. A linear positive association was observed between the number of cigarettes smoked and offspring overweight for up to 15 cigarettes per day with an OR increase per cigarette of 1.03, 95% CI = [1.02-1.03]. The OR flattened with higher cigarette use. Associations were similar in males and females. Sensitivity analyses supported these results. CONCLUSIONS: A linear dose-response relationship of maternal smoking was observed in the range of 1-15 cigarettes per day equally in boys and girls with no further risk increase for doses above 15 cigarettes.

Severe food insecurity is associated with obesity among Brazilian adolescent females.

OBJECTIVE: To determine whether household food insecurity (HFI) is associated with a higher prevalence of excessive weight (EW) in a large random sample of Brazilian female adolescents. DESIGN: Nationally representative cross-sectional study. EW was the outcome variable (BMI ≥ 85th percentile of WHO reference for adolescents aged 15-18 years and BMI ≥ 25 kg/m(2) for those aged 19 years). HFI was measured with the Brazilian Food Insecurity Scale. Associations were measured using crude and adjusted prevalence ratios (PR) with 95 % confidence intervals through Poisson regression models taking into account the complex sampling design. SETTING: Data were derived from the third wave of the Demographic and Health Survey conducted in 2006-2007, in Brazil. SUBJECTS: The sample included 1529 female adolescents aged 15-19 years. RESULTS: The prevalence of any level of HFI was 40.8 %, with 26.6 % of households experiencing mild, 9.4 % moderate and 4.8 % severe food insecurity. The overall prevalence of EW was 21.9 % (12.9 % were overweight and 9.0 % obese). EW prevalence among those living in severely, moderately and mildly food-insecure households was 36.8 %, 14.9 % and 16.5 %, respectively (P for the overall association = 0.036). Women living in severely food-insecure households had an increased prevalence of EW compared with their food-secure counterparts (PR = 1.96; 95 % CI 1.18, 3.27; P = 0.007), after adjusting for important confounders. CONCLUSIONS: The study suggests that severe but not mild or moderate HFI is independently associated with EW among adolescents residing in Brazil, a middle-income country undergoing the nutrition transition.

Cesarean delivery is associated with an increased risk of obesity in adulthood in a Brazilian birth cohort study.

BACKGROUND: Obesity is epidemic worldwide, and increases in cesarean delivery rates have occurred in parallel. OBJECTIVE: This study aimed to determine whether cesarean delivery is a risk factor for obesity in adulthood in a birth cohort of Brazilian subjects. DESIGN: We initiated a birth cohort study in Ribeirão Preto, southeastern Brazil, in 1978. A randomly selected sample of 2057 subjects from the original cohort was reassessed in 2002-2004. Type of delivery, birth weight, maternal smoking, and schooling were obtained after birth. The following data from subjects were collected at 23-25 y of age: body mass index (BMI; in kg/m(2)), physical activity, smoking, and income. Obesity was defined as a BMI ≥30. A Poisson multivariable model was performed to determine the association between cesarean delivery and BMI. RESULTS: The obesity rate in adults born by cesarean delivery was 15.2% and in those born by vaginal delivery was 10.4% (P = 0.002). Adults born by cesarean delivery had an increased risk (prevalence ratio: 1.58; 95% CI: 1.23, 2.02) of obesity at adulthood after adjustments. CONCLUSION: We hypothesize that increasing rates of cesarean delivery may play a role in the obesity epidemic worldwide.