Dose-response associations between maternal smoking during pregnancy and subsequent childhood obesity: effect modification by maternal race/ethnicity in a low-income US cohort.
ABSTRACT Studies suggest that children exposed to cigarette smoke in utero are at risk of becoming obese. Few researchers have evaluated the dose-response association between maternal smoking during pregnancy and childhood obesity or whether this association varies by maternal race/ethnicity. The authors obtained retrospective cohort data by linking records from the Pregnancy Nutrition Surveillance System and the Pediatric Nutrition Surveillance System on 155,411 low-income children born during 1995-2001 in 9 US states and 2 tribal nations. The authors examined maternal smoking status, duration of smoking, quantity of smoking, and both duration and quantity combined. Childhood obesity was based on a body mass index greater than or equal to the 95th percentile for sex and age, assessed at age 2-4 years. Maternal race/ethnicity modified the association between smoking during pregnancy and childhood obesity. Among non-Hispanic White mothers, both duration and quantity of smoking were positively associated with childhood obesity in a dose-response manner. Among non-Hispanic Black mothers, only heavy smoking was positively associated with childhood obesity. Among Hispanics, American Indians/Alaska Natives, and Asians/Pacific Islanders, smoking was not associated with childhood obesity. The inconsistent association between smoking during pregnancy and childhood obesity across race/ethnicity categories merits further investigation into potential explanations for this variation, which may include confounding, reporting bias, or unexplored biologic mechanisms.
Full-textDOI: · Available from: Andrea J Sharma, Sep 05, 2014
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ABSTRACT: Breastfeeding provides infants with nutrients that protect against risk of overweight but can also expose the infant to significant amounts of tobacco compounds when the mother smokes. Thus, a question arises regarding the joint effect of maternal smoking and breastfeeding on risk of overweight and growth during infancy. Methods - We used data (N=23,571) from the Collaborative Perinatal Project to conduct the first study of the net effect of exposure to tobacco compounds via breast milk on growth and risk of overweight during infancy. We stratified infants by maternal smoking and feeding type, and fit interaction terms to isolate the net effect of exposure to tobacco compounds via breast milk from exposure in uterus and in ambient air after birth. Results - The risk of overweight at 1 year of age associated with maternal smoking among breastfed infants was similar with that among bottle-fed infants. The association between maternal smoking and infancy weight gain was marginally greater among breastfed infants (adjusted mean difference, 0.23 kg [95% CI, 0.08 to 0.38]) than among bottle-fed infants (0.14, [95% CI, 0.09 to 0.19]). Conclusions - Among this sample maternal smoking and breastfeeding each appear to be associated primarily with the risk of overweight through influencing the upper tail of the BMI distribution rather than shifting the entire BMI distribution. Implications of these findings are discussed in terms of catch-up growth, confounding by SES, and potential biologic pathways.141st APHA Annual Meeting and Exposition 2013; 11/2013
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ABSTRACT: Background: Some studies reported similar effect estimates for the impact of maternal smoking in pregnancy and paternal smoking on childhood obesity, whereas others suggested higher effects for maternal smoking. We performed a meta-analysis to compare the effect of in utero exposure to maternal smoking and that of paternal or household smoking exposure in utero or after birth with mutual adjustment. Methods: Meta-analysis of observational studies identified in MEDLINE, EMBASE and Web of Knowledge published in 1900-2013. Study inclusion criterion was assessment of the association of maternal smoking during pregnancy and paternal or household smoking (anyone living in the household who smokes) at any time with childhood overweight and obesity. The analyses were based on all studies with mutually adjusted effect estimates for maternal and paternal/household smoking applying a random-effects model. Results: Data for 109 838 mother/child pairs were reported in 12 studies. The pooled odds ratios (ORs) for overweight 1.33 [95% confidence interval (CI) 1.23; 1.44] (n = 6, I-2 = 0.00%) and obesity 1.60 (95% CI 1.37; 1.88) (n = 4, I-2 = 32.47%) for maternal smoking during pregnancy were higher than for paternal smoking: 1.07 (95% CI 1.00; 1.16) (n = 6, I-2 = 41.34%) and 1.23 (95% CI 1.10; 1.38) (n = 4, I-2 = 14.61%), respectively. Similar estimates with widely overlapping confidence limits were found for maternal smoking during pregnancy and childhood overweight and obesity: 1.35 (95% CI 1.20; 1.51) (n = 3, I-2 = 0.00%) and 1.28 (95% CI 1.07; 1.54) (n = 3, I-2 = 0.00%) compared with household smoking 1.22 (95% CI 1.06; 1.39) (n = 3, I-2 = 72.14%) and 1.31 (95% CI 1.15; 1.50)] (n = 3, I-2 = 0.00%). Conclusions: Higher effect estimates for maternal smoking in pregnancy compared with paternal smoking in mutually adjusted models may suggest a direct intrauterine effect.International Journal of Epidemiology 07/2014; 43(5). DOI:10.1093/ije/dyu150 · 9.20 Impact Factor
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ABSTRACT: Recently, it has been suggested that fetal and infant environments are associated with childhood and adulthood health status, specifically regarding presence of obesity and chronic diseases. This concept is known as the "Developmental Origins of Health and Disease (DOHaD) hypothesis." Thus, it is necessary to collect information about the fetal and infancy periods in order to examine the association between fetal and infancy exposures and later growth. Based on the DOHaD hypothesis, childhood growth trajectories, which were described by multilevel analysis, might be important in examining the effects of early-life environment on later-life health. The author and colleagues examined the association between maternal smoking during pregnancy and fetal/childhood growth, specifically risk of childhood obesity, by using the dataset from an ongoing prospective cohort study called "Project Koshu," which enrolled pregnant women and their children from a rural area of Japan. Children born to smoking mothers were likely to have lower birth weights and, thereafter, to show an increase in body mass index compared to children of non-smoking mothers. Differences in pubertal growth patterns by gender and childhood weight status were then examined. Growth rate and height gain trajectories were similar between genders, although pubertal growth spurts were observed earlier in girls than in boys. The overweight/obese children grew faster than did the non-overweight children in the early pubertal stages, and the non-overweight children caught up and showed greater height gains at older ages. Because Project Koshu is ongoing, further studies examining new research questions will be conducted with larger sample sizes.Journal of Epidemiology 10/2014; 25(1). DOI:10.2188/jea.JE20140130 · 2.86 Impact Factor