Parental inheritance and perinatal tobacco smoke exposure increase the gender-dependent risk of physician diagnosed asthma at preschool age

Methods A birth cohort in southern Taiwan was studied. Information about parental allergic histories, gender, prematurity, TSE, and childhood allergic disease ever diagnosed by a physician were acquired from questionnaire during follow up. Children were asked to follow up at 6 years of age for allergic questionnaire and sensitization examination (CAP system). Results In this cohort study, 748 of the children with complete data were analyzed. 217 (29%) of children had positive parental allergic history, 191 (25.5%) of children had TSE history, and 186 (24.9%) of children had been diagnosed as asthma by a physician in the first 6 years of life. In a regression analysis, physician diagnosed asthma ever in the first 6 years of life were significantly associated with male gender (OR: 1.941, 95% CI: 1.371-2.748, p 0.5). Besides, TSE and parental allergic history had synergistic influence on the physician diagnosed asthma ever in the 6 years of life. This synergistic influence was significant in girls, rather than in boys (Table 1).