Ethnic variation in childhood asthma and wheezing illnesses: findings from the Millennium Cohort Study.

It is not clear how respiratory morbidity during early childhood varies across ethnic groups in the UK. This article seeks to determine whether asthma and wheeze illnesses during early childhood differ across ethnic groups and what factors explain observed differences. Data from the UK Millennium Cohort Study on 14,630 children were analyzed from the second sweep of interviews. Parental interviews were conducted when the cohort member was aged approximately 3(1/2) years. Data collected included the occurrence of asthma and wheezing symptoms, biological and socio-economic factors and markers of cultural tradition. At age 3, 12.3% (n = 1,902) of children had ever had asthma and 20.0% (n = 3,030) had wheezed in the last 12 months. 18.2% of Black Caribbean children and 5.0% of Bangladeshi children reported ever asthma compared with 11.6% of White children. 25.5% of Black Caribbean children and 8.7% of Bangladeshi reported recent wheeze compared with 19.4% of White children. After adjustments, the disadvantage in asthma and recent wheeze for Black Caribbeans was mostly explained by socio-economic factors (adjusted odds ratios (OR) for asthma 1.42, 95% confidence interval (CI) 0.96-2.09; recent wheeze 1.18, 0.85-1.64). The Bangladeshi advantage lost statistical significance, mostly due to adjustment for markers of cultural tradition (adjusted OR for asthma 0.40, 95% CI 0.15-1.09; recent wheeze 0.44, 0.18-1.19). Our results point to the need to locate child health within the unique context of each ethnic group and to recognize that potential explanations for observed differences do not necessarily hold for all groups.