Asthma, atopy and tuberculin responses in Chinese schoolchildren in Hong Kong

Background-The prevalence rates of asthma and other atopic disorders have i ncreased steadily in many developed countries over the past few decades. Re cent epidemiological and animal studies have suggested that BCG vaccination might be beneficial in reducing the subsequent development of atopy. This study investigates the relationship between asthma, allergic symptoms, atop y, and tuberculin response in Chinese schoolchildren who received BCG vacci nation at birth. Methods-A total of 3110 schoolchildren aged 10 years were recruited for the Hong Kong arm of the phase II International Study of Asthma and Allergies in Childhood. Of the 2599 children born in Hong Kong and vaccinated with BC G after birth, 2201 had tuberculin testing performed at a mean (SD) age of 8.4 (1.4) years. A random subsample of 980 children was also recruited for skin prick testing. Results-The prevalence rates of asthma ever, wheeze ever, current wheeze, c urrent rhinoconjunctivitis, and current flexural eczema were not significan tly different between tuberculin positive and negative subjects. The mean ( SE) tuberculin response was 3.4 (0.2) mm in atopic subjects and 3.3 (0.2) m m in non-atopic subjects (difference not significant). Logistic regression analyses did not reveal any significant relationship between asthma ever, c urrent wheeze, atopy, and positive tuberculin responses. Conclusions-This study did not find any relationship between asthma, allerg ic symptoms, atopy, and positive tuberculin reactivity in Chinese schoolchi ldren vaccinated with BCG at birth.