A pilot vitamin intervention trial in Linxian, People's Republic of China.

A 24-week pilot study of daily or weekly multiple vitamin supplementation among 852 adults in Linxian, where the rate of esophageal cancer is exceptionally high, demonstrated the feasibility of an intervention trial in this population. Compliance, when judged by pill count, was high for both frequencies of pill use. Only 2% of the subjects refused to take any pills, and, among pill takers, over 95% were reported to be taking most of their pills at the end of the study. Biochemical confirmation of high compliance was demonstrated in urine and blood tests, which showed markedly improved vitamin levels after supplementation. Results of the pilot study indicated that a system in which barefoot doctors were used in pill distribution was effective and that established field operating procedures for a full-scale intervention trial in this area were acceptable.