| Abstrakt: |
Vitamin D status and cancer risk has been investigated in a number of epidemiologic studies. The methods to estimate vitamin D status have included direct measures of circulating 25(OH)vitamin D (25(OH)D) levels, surrogates or determinants of 25(OH)D, including region of residence, intake, and sun exposure estimates. For colorectal cancer, the evidence for an inverse association between vitamin D status and risk is quite consistent. Evidence for breast cancer is intriguing, but prospective studies of 25(OH)D are sparse and conflicting. For prostate cancer, the data on circulating 25(OH)D have suggested no association or a weak inverse association, but studies of sun exposure on prostate cancer risk are more suggestive. It is plausible that for prostate cancer, vitamin D level, much longer before the time of diagnosis, is the most relevant exposure. Most of the epidemiologic studies to date have examined vitamin D status in relation to risk of cancer, but emerging evidence suggests that vitamin D may also be an important factor for cancer progression and mortality. Further study is needed to establish when in the life span and on what stages of carcinogenesis vitamin D is relevant, the precise intakes and levels required for benefit, and which cancer sites are most affected. [ABSTRACT FROM AUTHOR] |
