Dependence of immediate hypersensitivity on the month of birth

Abstract

This report describes a retrospective study of 1421 patients allergic to pollens [e.g., Betulaceae, Gramineae, Artemisia vulgaris] and 728 patients allergic to animal [e.g., cow, horse, cat, dog, guinea pig, hamster] epithelia. In males, but not in females, the mo. of birth distribution differed significantly from that in the total population of Finland (P < 0.01 in pollen allergy nd P < 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 and P < 0.001 in epithelium allergy). When the relative risk of immediate hypersensitivity was plotted as a function of the mo. of birth, a 2-phasic curve with maxima in March-May and Sept.-Nov. was obtained for pollen allergy and animal epithelium allergy. Boys, but perhaps not girls, apparently have a sensitive period early in life diring which 1 or more environmental factor and seasonal variations in this factor influence the development of subsequent immediate hypersensitivity.