RESUMO
Present study examined various socio-demographic factors, dietary patterns, habit of tobacco consumption and plasma vitamin levels in 56 healthy individuals, 146 patients with oral precancerous conditions (OPC) and 132 untreated oral and pharyngeal cancer patients. The subjects were interviewed with a detailed health, habit and diet questionnaire. Plasma b-carotene, vitamin-A and vitamin-E levels were determined spectrophotometrically. An increased incidence of OPC was observed in the age group of <30 years which was associated with tobacco chewing. Whereas, incidence of cancer was in the age group of 30-60 years where habit of tobacco smoking was more prevalent. Majorities of the subjects were from rural area, poor, unaware about association of diet with cancer. The body mass index was lower (p=0.045) in patients with OPC and cancer patients as compared to the controls. Plasma b-carotene and vitamin-E levels were lower in patients with OPC (p=0.000 and 0.031, respectively) and untreated cancer patients (p=0.000 and 0.071, respectively) than the controls. ROC curve revealed that plasma vitamin levels have ability to discriminate between controls and cancer patients. Lower plasma b-carotene and vitamin-E levels were observed in tobacco consumers as compared to non-consumers. Odds ratio revealed that controls and patients with OPC having tobacco habit and lower plasma levels of b-carotene were at a higher risk (p<0.05) of developing cancer. Regression study and Analysis of Variance revealed that plasma b-carotene levels were inversely associated (r(2)=0.14, p=0.001 and F=0.000, respectively) with increase in the stage of cancer. The data provide interesting clues of potential role of diet, tobacco habits, socio-demographic status and plasma vitamin levels in etiology of oral and pharyngeal cancer in Gujarat, where no such findings are reported.