Oral Mucosal Lesions Associated with Smokers and Chewers - A Case-Control Study in Chennai Population

To determine the association of oral mucosal lesions in a group of Chennai population aged 15 years and above with smoking and chewing habits. To also determine the dose-response relationship of these habits associated with the risk of oral mucosal lesions.

The study was undertaken with 450 subjects with smoking and/or chewing habits aged 15 years and over gathered through random selection in Chennai, India. Subjects with alcohol intake were excluded from the study. Based on the habits the study group was categorized into smokers, chewers and mixed (smoking+chewing). One hundred and fifty subjects diagnosed with oral mucosal lesions designated as "cases" and 300 lesion-free "controls", frequency matched for age, sex, habit and family income were assessed during the study. The study protocol included a visual oral soft tissue examination and a questionnaire-based interview. In addition, those requiring further examination, scalpel biopsies were performed to establish a definitive diagnosis.

Irrespective of the type of habit, 78% of cases smoked and/or chewed for more than 10 years as compared to 37.4% of the control group. Similarly, 71.3% of cases smoked and/or chewed more than 5 times per day as compared to 25.6% of the control group. Eleven habits related mucosal lesions of the oral cavity were encountered. Smoker's melanosis was the most common oral mucosal lesion followed by Oral submucous fibrosis and Leukoplakia. Dose-response relationships were observed for both duration and frequency of habits on the risk of oral mucosal lesions.

The result of the present study provides information on the association of oral mucosal lesions in smokers, chewers and patients with mixed habits. The mucosal lesions encountered included a few potentially malignant conditions and oral squamous cell carcinoma. Habits were more prevalent in men thus more lesions were encountered in males than in females. Moreover, increase in the duration and frequency of habits was significant predictors of risk in the case population.