Association Between Maternal Smoking and Childhood Obesity
Yes, there is a significant association between maternal smoking during pregnancy and childhood obesity, with evidence showing a dose-dependent relationship and increased risk that persists even after adjusting for confounding factors. 1
Evidence for the Association
Maternal smoking during pregnancy is associated with an increased risk of the child being overweight at 3 years of age (adjusted OR: 1.33 [95% CI: 1.15-1.55]) 1
A meta-analysis of studies published from 1990 to 2011 confirmed this effect, showing that maternal smoking during pregnancy increases the risk of children being overweight (adjusted OR: 1.47 [95% CI: 1.26-1.73]) 1
The association demonstrates a dose-response relationship, with higher cigarette consumption during pregnancy linked to greater risk of childhood obesity 2
Strength and Timing of Association
Children whose mothers smoked during pregnancy have higher adiposity levels across several measures compared to children of non-smokers 3
The median BMI difference between children of smokers and non-smokers was 0.39 kg/m² in boys and 0.46 kg/m² in girls 3
Waist circumference was also greater in children of smokers (0.55 cm in boys and 0.82 cm in girls) 3
The association appears stronger with increasing age of the child 3
Smoking Cessation and Risk Reduction
Compared to children of non-smokers, the pooled unadjusted odds ratio for overweight was 1.36 (95% CI: 1.14-1.62) in children of mothers who quit smoking and 1.44 (95% CI: 1.27-1.64) in children of continued smokers 4
For obesity specifically, the pooled unadjusted odds ratio was 1.65 (95% CI: 1.17-2.32) in children of quitters and 1.94 (95% CI: 1.38-2.73) in children of continued smokers 4
Timing of cessation matters: quitting before pregnancy is ideal, but quitting in early pregnancy still helps reduce the risk 4
Exposure Timing and Postnatal Effects
Both prenatal and postnatal tobacco smoke exposure contribute to childhood obesity risk 5
Exposure to tobacco smoke during the first years of life appears to be a key risk factor for development of childhood overweight 5
Children exposed to smoke both in the first year and at age six had the highest risk (OR: 4.43 [95% CI: 2.24-8.76]) 5
Geographic Consistency
The association between maternal smoking during pregnancy and childhood overweight has been observed across multiple countries and populations 6
A study across six Central/Eastern European countries found a mean odds ratio of 1.26 (95% CI: 1.03-1.55) for the association between maternal smoking and childhood overweight 6
The strength of association may vary by socioeconomic conditions, with stronger associations observed in more affluent settings 6
Clinical Implications
The relationship between maternal smoking and childhood obesity represents an important modifiable risk factor for childhood obesity 4
Interventions to help mothers quit smoking have the potential to reduce the risk of childhood overweight and obesity related to prenatal tobacco exposure 4
The effects appear to be due to intrauterine exposure to inhaled smoke products rather than lifestyle factors associated with maternal smoking 2