The association between maternal smoking during pregnancy and childhood obesity persists to the age of 9-10 years.
BACKGROUND
We previously reported that a number of factors related to maternal lifestyle during early pregnancy, including smoking, are associated with childhood obesity at 5 years of age. In the present study, we investigated whether the association with maternal smoking persisted to the age of 9-10 years.


METHODS
The study population comprised children born between April 1, 1991 and March 31, 1999, and their mothers. The dependent variables--childhood overweight and obesity at 5 and 9-10 years of age--were defined according to internationally acknowledged cut-off values. Maternal smoking during early pregnancy was used as the independent variable.


RESULTS
Mothers who completed a specifically designed questionnaire gave birth to a total of 1644 infants during the study period. Anthropometric data were collected from 1302 of these children during medical checkups at 9-10 years of age (follow-up rate: 79.2%). Maternal smoking during early pregnancy was associated with obesity in 9- to 10-year-old children (adjusted odds ratio, 1.91; 95% confidence interval, 1.03-3.53). However, the point estimates at the age of 9-10 years were considerably lower than those at the age of 5 years.


CONCLUSIONS
Our results suggest that fetal environment, including exposure to maternal smoking, continues to be associated with childhood obesity at the age of 9-10 years.
Suzuki
Kohta
K
Department of Health Sciences, School of Medicine, University of Yamanashi, Chuo, Yamanashi, Japan.
Ando
Daisuke
D
Sato
Miri
M
Tanaka
Taichiro
T
Kondo
Naoki
N
Yamagata
Zentaro
Z
D001837:Body Weights and Measures; D002648:Child; D002675:Child, Preschool; D004032:Diet; D005260:Female; D015438:Health Behavior; D006801:Humans; D008019:Life Style; D009035:Mothers; D009765:Obesity / Q000453:epidemiology* / Q000209:etiology; D050177:Overweight / Q000453:epidemiology / Q000209:etiology; D011247:Pregnancy; D011297:Prenatal Exposure Delayed Effects / Q000453:epidemiology* / Q000209:etiology; D011446:Prospective Studies; D012890:Sleep; D012907:Smoking / Q000009:adverse effects*