Vitamin D helps fight colorectal cancer, precursor lesions in young women

Increased intake of vitamin D appears to reduce the risk of developing early-onset colorectal cancer and its precursor lesions in young women, as suggested in a study.

The analysis included women enrolled in the Nurses’ Health Study II. Multivariable Cox proportional hazards and logistic regression models were used to estimate the association between total vitamin D intake and the risks of CRC and precursors diagnosed before age 50 years.

From 1991 to 2015, a total of 111 incident cases of early-onset CRC were documented during 1,250,560 person-years of follow-up. These occurred less frequently in the group of women with increased vitamin D intake. Meanwhile, there were 1,439 cases of conventional adenoma and 1,878 cases of serrated polyp.

In Cox models, the risk of developing early-onset CRC was cut by half among women with vitamin D intake of ≥450 IU/day compared with those who had less (<300 IU/day; hazard ratio [HR], 0.49, 95 percent confidence interval [CI], 0.26–0.93; p_trend=0.01). Furthermore, each 400 IU/day increase in intake conferred a 54-percent risk reduction (HR, 0.46, 95 percent CI, 0.26­–0.83).

The chemopreventive effect against CRC was significantly pronounced with dietary sources of vitamin D (per 400 IU/day increase: HR, 0.34, 95 percent CI, 0.15–0.79) than with supplemental vitamin D (400 IU/day increase: HR, 0.77, 95 percent CI, 0.37–1.62).

With respect to CRC precursors, each 400-IU/day increase in vitamin D intake reduced the likelihood of conventional adenoma by 24 percent (odds ratio [OR], 0.76, 95 percent CI, 0.65–0.88) and serrated polyp by 15 percent (OR, 0.85, 95 percent CI, 0.75–0.97).