To reduce the large age difference between the two offspring cohorts, we applied sensitivity analyses using more narrow time windows with offspring born 10 or 5 years before or after ECRHS I. For both models, the point estimates for offspring asthma with hayfever remained higher for parental disease activity (BHR and specific IgE) measured before rather than after conception (Table 3A and B). Here, IGHE is linked to asthma.