[Does the moment of birth have any significance on recognition of atopic diseases of the respiratory system? II. Incidence of atopic diseases in relation to birth date of children from families with increased atopic diathesis].

The aim of this study was to analyze the birth rates in specific quarters of the year in families with a history of atopic diathesis. One hundred families with atopic diathesis with at least two children older than 16 years were studied. The diagnosis of its atopic etiology and demonstration of the specific allergen were all based on results of a questionnaire, physical examination, results of skin tests and serum levels of allergen specific IgE. In the selected 100 families an analysis of birth rates of 251 children was carried out in each quarter of the year and the effect of this on first atopy symptoms was searched for. It was demonstrated that in these families more children were born with atopy (57%) than without. More than half of the children were sensitive to grass pollens and perennial allergens, and only 20% to the perennial allergens. Most children were born during the second quarter of the year. In this group atopy was four fold more often seen. The results demonstrate that the birth date of children from atopic families is a risk factor for atopy. This implies that family planning should be added to the list of secondary prophylactic measures of atopic diseases.