Association of pre- and post-natal parental smoking with offspring body mass index: An 8-year follow-up of a birth cohort

Division of Clinical Epidemiology and Aging Research, German Cancer Research Center (DKFZ), Heidelberg, Germany.
Pediatric Obesity (Impact Factor: 4.57). 02/2013; 9(2). DOI: 10.1111/j.2047-6310.2012.00146.x
Source: PubMed


Although many epidemiological studies have shown an association between maternal smoking during pregnancy and offspring overweight, it is still under debate whether intrauterine tobacco smoke exposure directly affects offspring obesity or if the association is rather due to confounding by lifestyle factors. The association of parental smoking habits at pre- and post-natal periods with offspring body mass index (BMI) was investigated, whereas maternal smoking during pregnancy was validated by cord serum cotinine measurements. Multivariable linear regression analysis, based on the German Ulm Birth Cohort Study of 1045 children born in 2000 with annual/biennial follow-up until the age of 8 years (n = 609), was conducted. BMI of offspring from mothers who smoked during pregnancy and non-smoking mothers differed significantly at 8 years. Maternal smoking during pregnancy was associated with an increase in BMI of 0.73 kg m−2 [95% confidence interval: 0.21–1.25] in 8-year-old children after adjustment for multiple potential confounding variables. Both pre- and post-natal smoking of fathers (0.34 [0.01–0.66]/0.45 [0.08–0.81]) and of both parents (1.03 [0.43–1.63]/0.56 [0.14–0.98]) were likewise significantly associated with offspring BMI. The observed patterns suggest that residual confounding by living conditions in smoking families rather than specific intrauterine exposure to tobacco smoke may account for the increased risk of offspring overweight.

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    • "At lower quantiles the association was more pronounced in girls than in boys, whereas for higher quantiles the association was more pronounced and increased to a greater extent over time in boys compared with girls. Some previous studies have compared BMI or BMI z-scores in cohorts of children of smoking and nonsmoking mothers in repetitive cross-sectional analyses (Florath et al. 2013; Fried et al. 1999; Power and Jefferis 2002; Vik et al. 1996). The time period varied from birth to 33 years of age, although not all studies considered the life course since birth (Power and Jefferis 2002). "
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