Grandmaternal smoking, asthma and lung function in the offspring: the Lifelines cohort study

BACKGROUND/OBJECTIVE: Limited research exists regarding the association between grandmaternal smoking during pregnancy and the risk for asthma and altered lung function in grandchildren. This study aimed to investigate this association in a three-generation design. METHODS: 37 291 participants (25 747 adults and 11 544 children) were included from the Lifelines study, a prospective longitudinal three generation cohort study in The Netherlands. Spirometry was available in 69.5% and 61.1% of the included adults and children. Logistic and linear regression were used to analyse the association between grandmaternal smoking during pregnancy and (1) asthma, (2) early childhood asthma (ie, onset before 6 years) and (3) lung function level. Maternal and paternal grandmaternal smoking were studied separately and the analyses were stratified by adult/child and by gender. The analyses were adjusted for gender, current smoking, birth variables and socioeconomic status. RESULTS: In the adult population, maternal grandmaternal smoking during pregnancy was associated with a higher risk for asthma (OR (95% CI): 1.38 (1.06 to 1.79)), early childhood asthma (1.49 (95% CI 1.06 to 2.11)) and a lower FEV1/FVC% predicted (B (95% CI): −1.04 (−1.91 to −0.16) in men. These findings were not observed in a separate analysis of children that participated in this study. There was also no significant association between paternal grandmaternal smoking and asthma/lung function. CONCLUSION: Maternal grandmaternal smoking during pregnancy is associated with higher asthma risk and lower lung function in male grandchildren and a reverse effect in male grandchildren of subsequent generations. Our study highlights the deep-rooted effects of tobacco smoking across generations.