Indians, Bangladeshis and Black Africans have a similar or lower prevalence of asthma than White children, while Black Caribbean and Mixed Black Caribbean/White boys are more likely to have asthma, according to a study of UK schoolchildren.
In the study, the researchers examined the occurrence of asthma, and probed ethnic differences in risk factors.
Melissa Whitrow and Seeromanie Harding from the Social and Public Health Sciences Unit of the Medical Research Council, UK, used data taken from 51 London schools to investigate a random selection of 11-13 year old pupils.
In the final sample for analysis, there were 1219 children who identified themselves as 'White UK', 933 'Black Caribbean', 1095 'Black African', 459 'Indian', 215 'Pakistani', 392 'Bangladeshi' and 299 'Mixed White UK and Black Caribbean'.
"Social and environmental factors may influence risk of asthma through early life exposures regulating the allergic inflammatory response and/or later life exposures to allergens. A positive association between body mass index (BMI) and asthma has also been reported. We aimed to investigate the influence of these factors on ethnic differences in asthma prevalence," said Whitrow and Harding.
The researchers found that a family history of asthma and psychological well being were consistent correlates for asthma regardless of ethnicity.
They observed that less than six years of residence in the UK had an independent protective effect for Black Caribbeans and Black Africans, possibly reflecting continuing protection from early life exposures in their home countries.
A gender difference was observed for Indians and Bangladeshis, with less asthma in girls than boys.
"These findings point to early protective influences which are not properly understood. International comparisons could provide useful insights into prevention of asthma, for ethnic minority children and for all children," said the authors, speaking about these results.
The study has been published in the open access journal BMC Pediatrics.