Dependence of immediate hypersensitivity on the month of birth

摘要

SummaryThis report describes a retrospective study of 1421 patients allergic to pollens and 728 patients allergic to animal epithelia. In males, but not in females, the month‐of‐birth distribution differed significantly from that in the total population of Finland (P<0·01 in pollen allergy andP<0·05 in epithelium allergy). The phenomenon was most clearly apparent in boys aged 10–14 born in 1960–4 (P<0·01 in pollen allergy andP<0·001 in epithelium allergy). When the relative risk of immediate hypersensitivity was plotted as a function of the month of birth, a two‐phasic curve with maxima in March–May and September–November was obtained for both pollen allergy and animal epithelium allergy. The results indicate that boys, but perhaps not girls, have a sensitive period early in life during which one or more environmental factor and seasonal variations in this factor influence the development of subsequent immediate