Effects of in utero and Postnatal Exposure to Secondhand Smoke on Lung Function by Gender and Asthma Status: The Seven Northeastern Cities (SNEC) Study.

Background: Little information exists on whether gender or asthma status modifies the effects of secondhand smoke (SHS) exposure on lung function. Objective: To evaluate whether gender or asthma status modifies the association of SHS exposure with lung function. Methods: A total of 6,740 children (average 11.6 years) were recruited from 24 districts of 7 cities in northeast China in 2012. SHS exposure included exposure to environmental and maternal smoking both in utero and during early childhood (postnatal). Lung function was measured using electronic spirometers. Two-step regressions were used to analyze the association between SHS and lung function. Results: In utero and postnatal exposure to SHS was independently associated with decreased lung function in both genders; however, this association was greater among males. For example, when exposed to maternal smoking during pregnancy, the adjusted odds ratio (aOR). [ABSTRACT FROM AUTHOR]