Higher concentration of vitamin D correlated significantly with a lower risk for overall cancer and liver cancer, according to recently published data.
“Although the beneficial effects of vitamin D in the prevention of skeletal disorders have long been recognized, accumulating evidence suggests that the benefits may extend beyond bone health to include several chronic diseases, including cancer,” Sanjeev Budhathoki, MD, from the National Cancer Center, Tokyo, and colleagues wrote. “We observed that a higher circulating concentration of vitamin D was associated with a lower risk of subsequent cancer in a large Japanese population.”
The study included two cohorts of participants from the Japan Public Health Center-based Prospective Study. Patients completed questionnaires on demographic characteristics, past medical history and lifestyle-related factors. Budhathoki and colleagues also collected blood samples from all participants to determine circulating 25-hydroxyvitamin D concentration.
One cohort comprised 3,301 patients with cancer. The researchers also randomly selected 4,044 participants for a subcohort, of whom 405 had cancer.
Median 25-hydroxyvitamin D concentration was higher in plasma samples collected during the summer and autumn months among the subcohort participants compared with samples collected in spring and winter (P < .001).
The researchers found that a higher 25-hydroxyvitamin D concentration correlated with a significantly lower risk for overall cancer after adjusting for age and sex (P = .003) and after further adjustment including BMI, smoking history, alcohol use, physical activity, family history of cancer and history of diabetes (P = .001).
At specific sites, 25-hydroxyvitamin D concentration demonstrated a significant inverse association with risk for liver cancer (P = .006) and premenopausal breast cancer (P = .03). Regarding liver cancer, additional adjustment for dietary factors including total energy intake, fruits and vegetables, meat, fish and shellfish, isoflavone, green tea and coffee slightly attenuated the association, but it remained significant.
Subgroup analysis by sex showed no significant difference in the effect of vitamin D on risk for cancer between sexes.
“Our findings support the hypothesis that vitamin D may confer protection against the risk of cancer,” Budhathoki and colleagues wrote. “Nevertheless, the lower risk associated with higher circulating vitamin D concentration seemed to show a ceiling effect, which may suggest that although maintaining an optimal 25-hydroxyvitamin D concentration is important for prevention of cancer, having a concentration beyond this optimal level may provide no further benefit.” – by Talitha Bennett
Disclosure: The authors report no relevant financial disclosures.