A case-control study design was employed to evaluate the risk
factors for multiple oral premalignant lesions. Data from the first
round of intervention from an on-going randomized oral cancer
screening trial in Kerala, India were used. The analysis included
only the intervention group since subjects from this group had
been screened with oral visual inspections and their disease status
was known. The objective of the randomized oral cancer screening
trial is to evaluate the efficacy of oral visual inspections by trained
health workers in preventing death from this cancer.8 The randomization
unit was the panchayath (n13), which is a rural administrative
structure. Subjects who were over the age of 35 years and
living in one of the specified panchayaths were eligible for the
trial. The intervention group included a total of 59,894 eligible
subjects who lived in 1 of 7 panchayaths, where the total resident
population was 172,567. In the first round of intervention, 49,179
(82.1%) subjects were interviewed and screened in their houses by
trained health workers. A total of 115 multiple oral premalignant