Incidence of oral leucoplakias among 20,358 Indian villagers in a 7-year period.

A group of 20,358 villagers in two districts of India has been followed for 7 years to study the incidence of oral leucoplakia. The follow-up rate of the population in two districts ranged from 61% to 71%. In one of the districts (Bhavnagar) no new cases of leucoplakia were found among females in the 7-year period. Among males 105 cases developed (4-0/1000/year). The incidence was highest among hookli (clay pipe) smokers. In the Ernakulam district the incidence among males was 3-3/1000/year whereas among females it was 1-9/1000/year. The mixed habits group had the highest incidence of oral leucoplakias (7-2 and 9-9/1000/year among males and females respectively).