Vitamin D intake, blood 25(OH)D levels, and breast cancer risk or mortality: a meta-analysis.
BACKGROUND
Experimental studies suggest potential anti-carcinogenic properties of vitamin D against breast cancer risk, but the epidemiological evidence to date is inconsistent.


METHODS
We searched MEDLINE and EMBASE databases along with a hand search for eligible studies to examine the association between vitamin D status (based on diet and blood 25-hydroxyvitamin D (25(OH)D)) and breast cancer risk or mortality in a meta-analysis. A random-effect model was used to calculate a pooled adjusted relative risk (RR).


RESULTS
A total of 30 prospective studies (nested case-control or cohort) were included for breast cancer incidence (n=24 studies; 31 867 cases) or mortality (n=6 studies; 870 deaths) among 6092 breast cancer patients. The pooled RRs of breast cancer incidence for the highest vs the lowest vitamin D intake and blood 25(OH)D levels were 0.95 (95% CI: 0.88-1.01) and 0.92 (95% CI: 0.83-1.02), respectively. Among breast cancer patients, high blood 25(OH)D levels were significantly associated with lower breast cancer mortality (pooled RR=0.58, 95% CI: 0.40-0.85) and overall mortality (pooled RR=0.61, 95% CI: 0.48-0.79). There was no evidence of heterogeneity and publication bias.


CONCLUSIONS
Our findings suggest that high vitamin D status is weakly associated with low breast cancer risk but strongly associated with better breast cancer survival.
Department of Food and Nutrition, Kyung Hee University, 26 Kyunghee-daero, Dongdaemun-gu, Seoul, South Korea.
Y
Y
Kim
Department of Food and Nutrition, Kyung Hee University, 26 Kyunghee-daero, Dongdaemun-gu, Seoul, South Korea.
Y
Y
Je
D001943:Breast Neoplasms / Q000097:blood* / Q000401:mortality / Q000517:prevention & control; D004032:Diet; D005260:Female; D006801:Humans; D011446:Prospective Studies; D012306:Risk; D014807:Vitamin D / Q000031:analogs & derivatives* / Q000097:blood
D014807:Vitamin D; C104450:25-hydroxyvitamin D