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Vitamin D and Risk for Breast Cancer According to Hormone-Receptor Status

Vitamin D protected against breast cancer, regardless of ER/PR status.

Evidence suggesting that vitamin D supplementation protects against several malignancies, including breast cancer, continues to accumulate (JW Womens Health Aug 2 2007). In an earlier population-based case-control study, Canadian investigators showed that higher vitamin D exposure during adolescence and young adulthood was associated with less risk for breast cancer later in life. Now, these investigators have assessed whether such protection varies by tumor hormone-receptor status. The association between vitamin D and breast cancer incidence was evaluated according to route of vitamin D acquisition (dietary intake or sun exposure) and tumor receptor status (estrogen receptor–positive/progesterone receptor–positive [ER+/PR+], 450; ER+/PR–, 110; ER–/PR–, 199). Mean age of cases and controls (1135) was 53; most women were of European descent.

Vitamin D exposure during adolescence and early adulthood (from cod liver oil, milk, vitamin supplements, and sun exposure) was associated with attenuated risk for breast cancer, particularly for ER+/PR+ tumors. However, differences in degree of protection were few and inconsistent among the three subsets of cases defined by ER/PR status.

Comment: Although lower risk associated with vitamin D exposure was shown most consistently for ER+/PR+ tumors, the result might simply reflect that this tumor subtype was the most common. Nonetheless, these findings support vitamin D’s beneficial effects on breast cancer risk, regardless of hormone-receptor status. Sun exposure and dietary intake (Table 1) are key sources of vitamin D.

The American Academy of Pediatrics recently raised its recommended daily vitamin D intake from 200 IU to 400 IU for children. The National Osteoporosis Foundation recommends that adults who are younger than 50 consume 400 IU to 800 IU of vitamin D daily and that older adults (age, 50) consume 800 IU to 1000 IU. As most multivitamins contain 400 IU of vitamin D, I recommend to my patients that they take not only a daily multivitamin but also twice-daily supplemental calcium plus vitamin D. One common supplement, Caltrate 600 + D, contains 400 IU of vitamin D per tablet. (Total daily dietary intake of vitamin D should not exceed 2000 IU.)

— Andrew M. Kaunitz, MD

Published in Journal Watch Women's Health November 13, 2008

Citation(s):

Blackmore KM et al. Vitamin D from dietary intake and sunlight exposure and the risk of hormone-receptor-defined breast cancer. Am J Epidemiol 2008 Oct 15; 168:915.

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