Multi‐ethnic variations in the practice of oral cancer risk habits in a developing country

Objective To elucidate ethnic variations in the practice of oral cancer risk habits in a selected Malaysian population. Methods This retrospective case–control study involves 790 cases of cancers of the oral cavity and 450 controls presenting with non‐malignant oral diseases, recruited from seven hospital‐based centres nationwide. Data on risk habits (smoking, drinking, chewing) were obtained using a structured questionnaire via face‐to‐face interviews. Multiple logistic regression was used to determine association between risk habits and oral cancer risk; chi‐square test was used to assess association between risk habits and ethnicity. Population attributable risks were calculated for all habits. Results Except for alcohol consumption, increased risk was observed for all habits; the highest risk was for smoking + chewing + drinking (aOR 22.37 95% CI 5.06, 98.95). Significant ethnic differences were observed in the practice of habits. The most common habit among Malays was smoking (24.2%); smoking + drinking were most common among Chinese (16.8%), whereas chewing was the most prevalent among Indians (45.2%) and Indigenous people (24.8%). Cessation of chewing, smoking and drinking is estimated to reduce cancer incidence by 22.6%, 8.5% and 6.9%, respectively. Conclusion Ethnic variations in the practice of oral cancer risk habits are evident. Betel quid chewing is the biggest attributable factor for this population.