The association of folate and cobalamin levels with oral premalignancy in female South Indian tobacco and betel quid chewers

A growing body of research suggests that nutritional factors can play a significant part in the carcinogenic process. Although the antioxidant micronutrients have received the most attention in the past, several recent investigations have explored the roles that folate and cobalamin might have in carcinogenesis. The intent of this study is to examine the association between the dietary and systemic levels of folate and/or cobalamin and risk for oral premalignancy. The study population, rural female South Indian tobacco and betel quid chewers have been shown to have a high prevalence of oral premalignancy and typical diets low in folate and cobalamin.

313 rural Hindu women, aged 20-60, who chewed at least one quid daily were visually examined for oral premalignancy. 158 were diagnosed as cases (one or more lesions), with the remaining 155 used as controls. A food frequency survey determined that those who consumed less than the mean for Foods of Animal Origin (Odds Ratio (OR) = 3.0; 95%CI 1.6-6.0), Vegetables and Fruit (OR = 1.9; 95%CI 1.2-3.8), and Green Leafy Vegetables (OR = 1.7; 95%CI 1.1-3.0) were at elevated risk for oral premalignancy. Greatest risk was found in a diet low in both Animal Foods and Vegetables (OR = 5.4; 95%CI 1.7-22.2). Plasma retinol, folate, cobalamin, ascorbate, carotenes, and $\alpha$-tocopherol and RBC folate levels were measured in 50 cases and 52 controls. Women with plasma levels below the 25th percentile were at higher risk than women above the 75th percentile for cobalamin (OR = 6.8; 95%CI 1.7-28.9), folate (OR = 8.1; 95%CI 2.0-36.4) and total carotenes (OR = 4.0; 95%CI 1.1-16.5). This suggests that dietary inadequacies leading to low systemic levels of cobalamin, folate, and carotenes may be significant factors in the carcinogenic process among female Indian tobacco/betel quid chewers.