Serum 25-Hydroxyvitamin D and Colon Cancer: Eight-Year Prospective Study
This study investigated the association between vitamin D blood levels and risk of getting colon cancer. Data from 34 patients were compared with data from 67 participants without cancer. The results showed that the risk of colon cancer decreased in people with higher blood levels of vitamin D. Further details can be found in the study.
Garland CF, Comstock GW, Garland FC, Helsing KJ, Shaw EK, Gorham ED. Serum 25-hydroxyvitamin D and colon cancer: eight-year prospective study. Lancet. 1989 Nov 18;2(8673):1176-8.