Toppila-Salmi S, Luukkainen AT, Xu B, et al. - Using questionnaire and clinical data of 5,200 people, free of physician-diagnosed asthma by the age 31 years, of Northern Finland Birth Cohort 1966 Study, researchers explored the connection between prenatal environmental tobacco smoke exposure (ETS) and adult onset asthma. Through adjusted multivariate regression analyses, the correlation of maternal smoking during the last three months of pregnancy with onset of physician-diagnosed asthma and with lung function in adult offspring were analyzed. Findings suggested an association of maternal smoking during pregnancy with the cumulative incidence of asthma in offspring between 31 and 46 years. In offspring who reported having past respiratory problems at age 31 and/or who had haplotype rs11702779-AA, the correlation was accentuated. In offspring with gestational smoke exposure, a decrease in the FEV1/FVC ratio was also observed at 31 years of age. Such findings may indicate early vulnerability of the airways of offspring to ETS and their putative long term effects.