RELATIONSHIP BETWEEN VITAMIN AND CALCIUM SUPPLEMENT USE AND COLON-CANCER

The relationship between vitamin supplement use and colon cancer was a ssessed in a population-based case-control study among men and women a ged 30-62 years, Cases were 251 men and 193 women diagnosed with colon cancer in 1985-1989 in three counties in the Seattle metropolitan are a who were identified from the Surveillance, Epidemiology, and End Res ults cancer registry, Controls were 233 men and 194 women identified b y random digit dialing, Supplement use was assessed by questions on fr equency, duration, and dose per day (for individual supplements) or ty pe (for multivitamins) during the 10-year period ending 2 years before diagnosis, All results were adjusted for age and sex and were not con founded by other measured behaviors, The average daily intake of suppl emental vitamins A, C, E, folic acid, calcium, and multivitamins durin g the reference period were each associated with reduced risk of colon cancer (all P for trend <0.03), The strongest associations were for u se of vitamin E (odds ratio, 0.43; 95% confidence interval, 0.26-0.71 for greater than or equal to 200 IU/day versus none) and multivitamins (odds ratio, 0.49; 95% confidence interval, 0.35-0.69 for daily use v ersus no use; both P for trend <0.001). These two associations were al so significant using a stricter test of trend limited to supplement us ers, which reduces the effect of colinearity among these exposures, Be cause almost all vitamin D supplementation comes from multivitamin pil ls, the association of vitamin D use with colon cancer could not be di stinguished from that of multivitamin use, Clinical trials or cohort s tudies with long-term assessment would be needed before public health recommendations could be made about supplement use.