A strong synergism of low birth weight and prenatal smoking on XXXX in schoolchildren.

@entity1 @entity32 @entity6314 @entity566 @entity565
BACKGROUND: Prenatal smoke exposure is associated with airway @entity32 and @entity565 in @entity1 . It also increases the risk of low birth weight (LBW). LBW is associated with @entity6314 independently of smoking. OBJECTIVE: To study the independent and joint effects of prenatal smoking and LBW on childhood @entity565 . METHODS: In 1996, all @entity1 aged 7 to 8 years in 3 cities in northern Sweden were invited to an International Study of Asthma and @entity566 in Childhood questionnaire survey. This study focused on the follow-up of @entity1 aged 11 to 12 years, in which 3389 @entity1 (96%) participated. A subset of 2121 @entity1 underwent skin-prick testing. Self-reported physician-diagnosed @entity565 has been clinically validated. RESULTS: Mean birth weight was 3360 g in @entity1 exposed to prenatal smoking and 3571 g in nonexposed @entity1 (P < .001). The association of prenatal smoking with physician-diagnosed @entity565 was stronger in LBW @entity1 (risk ratio: 8.8 [95% confidence interval: 2.1-38]) than in normal birth weight @entity1 (risk ratio: 1.3 [95% confidence interval: 1.0-1.8]). LBW alone was not an independent predictor of @entity565 . These associations were similar in multivariate analysis, and the interaction term LBW   smoking was highly statistically significant. CONCLUSIONS: There was a strong interaction of LBW and prenatal-smoking on the risk of physician-diagnosed @entity565 , which has not been demonstrated previously. This was consistently seen with adjustment for known risk factors, including allergic sensitization. Plausibly, airway @entity32 from prenatal smoke exposure induces obstructive symptoms more easily in the underdeveloped airways of LBW @entity1 .
