Father's prepuberty overweight and adult lung function and height in future sons

Abstract

<b>Background:</b> Our previous study suggests fathers’ but not mothers’ onset of overweight in prepuberty increased adult asthma in future offspring (Johannessen A, JACI 2020). Potential impact on offspring’s adult lung function, and mediation through offspring overweight or height, are not known. <b>Objective:</b> We studied two-generation causal associations to estimate the causal effects of parents’ overweight in specific time windows on offspring’s adult lung function. <b>Methods:</b> We included 929 adult offspring (age, 18-54 years, 54% daughters) of 308 fathers and 388 mothers (age, 40-66 years). Counterfactual-based mediation models with offspring’s sex as a potential moderator were used to assess the direct and indirect (mediated through offspring’s overweight and/or adult height) effects of parents’ overweight on offspring’s lung function (pre-bronchodilator FEV1, FVC and FEV1/FVC) in adulthood, within the paternal and maternal lines. <b>Results:</b> Fathers’ overweight before puberty had a negative direct effect on sons’ FVC [beta(95%CI): -251 (-478, -19) mL], and&nbsp;a negative indirect effect, mediated through sons’ height, on sons’ FEV1 [beta (95%CI): -148 (-281, -54) mL] and FVC [-213 (-384, -79) mL]. The effects were not mediated through offspring’s own overweight. No direct and indirect effects were found on FEV1 or FVC in daughters or within the maternal line. <b>Conclusion:</b> Fathers’ overweight starting before puberty appears to cause lower FEV1 and FVC in their future sons, partly due to reduced adult height in the sons. The effects were not mediated through sons’ overweight. This was only found in the male line, from father to son.