Prevalence ofasthma andrisk factors among Chinese, Malay, andIndian adults inSingapore

Background -Theprevalence andmorbidity ofasthmavarygreatly amongdifferentethniccommunities and geographical locations, buttherolesof environmental andgenetic factors are notfully understood. Thedifferences in prevalence ofadultasthmaamongChinese, Malay,andIndian ethnic groupsin Singapore wereexamined, andtheextent towhichthesecouldbeexplained bypersonalandenvironmental factors were investigated. Methods-A stratified disproportionate randomsample(n=2868)of Chinese (n=1018), Malays(n=967), andIndians (n=883)ofbothsexeswasdrawnfrom households infive public housing estates, andan interviewer administered questionnaire wasusedtodetermine cumulative andcurrentprevalence of"physiciandiagnosed asthma"(symptoms withaphysician diagnosis ofasthma). Results -Lifetime cumulative prevalence (standardised tothegeneral population) of"physician diagnosed asthma"was 47% inmen and43% inwomen;12 monthperiod prevalences were2-4%and 2-0%,respectively. Cumulative prevalenceofasthmawassignificantly higher inIndians (6-6%) andMalays(6-0%) than inChinese (3-0%); period prevalences of asthmawere4-5%inIndians, 3*3%in Malays, and0-9%inChinese. Ownership ofcatsordogswas more frequent in Malays(15-4%) andIndians (11-2%) than inChinese (8-8%). Rugsandcarpets were alsomore frequently usedby Malays (52-2%) andIndians (40-7%) thanbyChinese(8-9%). Currentsmokingprevalenceswerehigher inMalays(27-3%) than inIndians (19-4%) andChinese(23-0%). MalaysandIndians didnothavehigher ratesofatopy(11-1% and15-2%, respectively) thanChinese (15-4%). Adjustment forthese factors inmultivariate analyses reducedthegreater oddsofasthmain Malays andIndians, butnottoasignificantextent. Conclusions - Thereareethnicdifferences intheprevalence ofasthmain Singaporewhich are not entirely explained by differences in smoking,