Regional variations in wheezing illness in British children: Effect of migration during early childhood

Abstract

Study objective - The aim was to examine the regional distribution of wheezing illness among British children, and the age at which geographical differences may be determined. Design - Cross sectional analyses and study of interregional migrants were used. Subjects - The subjects were national cohorts of British children born in 1958 and 1970. Measurements and main results - The regional distribution of wheezing illness showed significant heterogeneity at age 5 (1970 cohort) and 7 (1958 cohort). In both cohorts, children in Scotland had a low prevalence of wheeze, which could not be attributed to underreporting of mild cases. There was a less consistent tendency for high prevalence in Wales, and in the South Western and Midlands regions of England. In the 1958 cohort, the regional differentials diminished progressively with age and were negligible at age 23. There was a poor correlation between the regional distribution of childhood asthma and the common geographical pattern shown by eczema in infancy and hay fever at age 23. Analysis of interregional migrants suggested that the regional variation in each cohort at age 5-7 was primarily related to the region of current residence, and not to the region of birth. Conclusions - Genetic constitution, perinatal exposures, or early childhood experiences are unlikely to account for the regional variation in wheezing illness. Although local patterns of symptom reporting or disease labelling may be acquired by parents who move to a new region, environmental factors operating at a regional level probably determine the prevalence of asthma in primary school children. These influences do not appear to have long lasting effects upon the tendency to wheeze in adolescence and early adulthood.