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.

METHODS: This scoping review intended to investigate published studies on the current prevalence and incidence of oral cancer in LMICs. The review was conducted applying the search words "Oral Cancer" and "Mouth neoplasm" as the Medical Subject Heading (MeSH) major topic and "Epidemiology" and ("prevalence" OR "incidence") as the MeSH subheading; the search was supplemented by cross-references. Included studies met the following criteria: original studies, reporting of prevalence or incidence rates, population-based studies, studies in English language and studies involving humans.

RESULTS: The sample sizes ranged from 486 to 101,761 with 213,572 persons included. Buccal mucosa is one of the most common sites of oral cancer, associated with the widespread exposure to chewing tobacco. The incidence is likely to rise in the region where gutkha, pan masala, pan-tobacco and various other forms of chewing tobacco are popular.