Paternal snus use in puberty and increased risk for asthma and allergies in offspring: a RHINE/RHINESSA two-generation study

Background Evidence suggests that a father's smoking in puberty may adversely impact respiratory health in offspring, possibly through epigenetic changes in germ cells. This study investigates whether snus use starting in or after puberty influences respiratory health in future offspring. Methods We analysed Swedish data from RHINE (Respiratory Health in Northern Europe) parents and RHINESSA (Respiratory Health in Northern Europe, Spain and Australia) offspring by using mixed-effect logistic regression to assess the links between paternal snus initiation around puberty and offspring asthma, chronic bronchitis, rhinitis, and eczema, adjusting for paternal and offspring smoking. Results We identified 1090 offspring-father pairs. The offspring's median age was 29 years (17-51) and 55% were women. The maternal line (n = 1421) was not analysed, as <1% of mothers used snus in puberty. The offspring of fathers starting snus use in puberty (n = 89) had a higher risk of current allergic asthma [odds ratio (OR) 1.42; 95% confidence interval (CI) 1.02-1.97], at least three asthma symptoms with allergy (OR 1.13; 95% CI 1.10-1.21), chronic bronchitis (OR 2.17; 95% CI 1.04-4.54), and eczema (OR 1.45; 95% CI 1.27-1.65). Fathers' snus use starting after puberty (n = 252) showed no consistent associations with offspring outcomes. The effect estimates were consistent after excluding offspring using snus in puberty. Conclusion Paternal snus use starting in puberty was associated with a higher risk of asthma and other respiratory and allergic symptoms in offspring. These findings support the hypothesis that exposures in puberty may impact future generations' respiratory health, possibly through epigenetic changes. This highlights the need for research on exposures during this period and actions to prevent habits that could negatively impact future offspring's health.