Parental smoking and childhood obesity—is maternal smoking in pregnancy the critical exposure?

• Published in: International journal of epidemiology Vol. 37; no. 1; pp. 210 - 216
• Main Authors: von Kries, Rüdiger, Bolte, Gabriele, Baghi, Ladan, Toschke, André Michael
• Format: Journal Article
• Language: English
• Published: Oxford Oxford University Press 01.02.2008; Oxford Publishing Limited (England)
• Subjects: Biological and medical sciences; Child; Child Development - physiology; Child, Preschool; Confidence Intervals; Cross-Sectional Studies; Female; Follow-Up Studies; Growth and development; Humans; Incidence; Infant; Male; Medical sciences; Metabolic diseases; nutritional and metabolic diseases; Obesity; Obesity - epidemiology; Obesity - etiology; Odds Ratio; Parents; pre-natal nutritional physiology; pre-natal programming; Pregnancy; Prenatal Exposure Delayed Effects; Risk Assessment; Sensitivity and Specificity; Smoking - adverse effects; Tobacco Smoke Pollution - adverse effects; Tobacco, tobacco smoking; Toxicology; Germany, Bavaria; Growth and development; pre-natal nutritional physiology; nutritional and metabolic diseases; pre-natal programming; Obesity; Parent; Nutrition disorder; Tobacco smoking; Epidemiology; Pregnancy; Mother; Father; Public health; Nutritional status
• ISSN: 0300-5771; 1464-3685
• DOI: 10.1093/ije/dym239

Background The concept of priming of childhood obesity by prenatal exposure to maternal smoking is based on a number of consistent studies. A recent paper found similar associations between paternal smoking and childhood obesity, questioning the presumed causal effect attributed to the prenatal exposure. Is the relation to paternal smoking consistent? Does it explain the effect of maternal smoking before or in pregnancy? Methods Data from a cross sectional study on 5899 children in the setting of the 2005 school entrance health examinations in Bavaria were analysed. Associations between paternal smoking or maternal smoking before or in pregnancy and childhood obesity were assessed with adjustment for potential confounders. Results The children's mean age was 5.8 years. The unadjusted odds ratio for obesity and paternal smoking was 2.0 (95% CI: 1.5, 2.6) and similar to that for maternal smoking before or in pregnancy with 2.3 (95% CI: 1.8, 3.1). After adjustment for a number of potential confounders and paternal smoking at interview the odds ratio for maternal smoking before or in pregnancy and childhood obesity was 1.9 (95% CI: 1.3, 2.7). There was no evidence for interaction between paternal smoking and maternal smoking before or in pregnancy (P = 0.38). Conclusions Although of similar magnitude, the association of paternal smoking could only partially explain the effect of maternal smoking before or in pregnancy on childhood obesity. Whether this persistent association reflects residual confounding or causality is unclear.