Adequate vitamin D levels are necessary and beneficial for health. Based on the current definition of vitamin D adequacy (>30 ng/ml), deficiency plagues much of the world's population (Holick and Chen, 2008). Emerging epidemiological studies and clinical trials suggest that vitamin D, long known to be important in maintaining bone health, is also important for reducing the risk of cardiovascular disease, cancer, and autoimmune disease, as well as in supporting cognitive function (Stechschulte et al., 2009). All-cause mortality has been found to be reduced with vitamin D supplementation. As a result, improving patients' vitamin D status has become an essential aspect of preventive care.
Several lines of evidence suggest that vitamin D status may be important in melanoma development and progression. In vitro, some melanoma cell lines have been responsive to the antiproliferative and prodifferentiation effects of vitamin D (Reichrath et al., 2007). Vitamin D suppressed the growth of melanoma-derived xenografts in immunosuppressed mice (Eisman et al., 1987). In addition, a large case–control study of more than 1,000 patients found that dietary vitamin D intake reduced the risk of developing melanoma (Millen et al., 2004). However, other epidemiological studies have failed to find an association between vitamin D and melanoma development/progression (Weinstock et al., 1992).
Using data from a large prospective observational study evaluating the relationship between dietary supplement use and cancer risk, Asgari and colleagues (2009, this issue) studied more than 68,000 persons without melanoma from the Pacific Northwest to evaluate the effect of diet and dietary supplementation with vitamin D on melanoma development. This dataset was linked to the national Surveillance, Epidemiology, and End Results cancer registry. During the 10-year follow-up, through 2006, a total of 455 incident melanomas were identified. The authors did not find a reduction in the risk of developing melanoma associated with intake of vitamin D, dietary supplementation with vitamin D, or the combination of diet and supplementation.
Through the following questions, we examine this paper in greater detail. For brief answers, please refer to http://network.nature.com/group/jidclub.
QUESTIONS
- What are the reported health benefits of vitamin D?
- How might vitamin D affect melanoma development and/or progression?
- Describe the methods used in this study.
- What are some limitations to the methodology of this study?
- What are the findings of the study?
- What may be the clinical implications of this study and what future studies could be performed?
References
- Asgari MM, Maruti SS, Kushi LH, White E (2009) A cohort study of vitamin D intake and melanoma risk. J Invest Dermatol 129:1675–80
- Eisman JA, Barkla DH, Tutton PJ (1987) Suppression of in vivo growth of human cancer solid tumor xenografts by 1,25-dihydroxyvitamin D3. Cancer Res 47:21–5 | PubMed | ChemPort |
- Holick MF, Chen TC (2008). Vitamin D deficiency: a worldwide problem with health consequences. Am J Clin Nutr 87;1080S–6S | PubMed | ChemPort |
- Millen AE, Tucker MA, Hartge P, Halpern A, Elder DE, Guerry D et al. (2004) Diet and melanoma in a case–control study. Cancer Epidemiol Biomarkers Prev 13:1042–51 | PubMed | ISI | ChemPort |
- Reichrath J, Rech M, Moeini M, Meese E, Tilgen W, Seifert M (2007) In vitro comparison of the vitamin D endocrine system in 1,25(OH)2D3-responsive and -resistant melanoma cells. Cancer Biol Ther 6:48–55 | PubMed | ChemPort |
- Stechschulte SA, Kirsner RS, Federman DG Vitamin D: bone and beyond: rationale and recommendations for supplementation. Am J Med (in press)
- Weinstock MA, Stampfer MJ, Lew RA, Willett WC, Sober AJ (1992) Case-control study of melanoma and dietary vitamin D: implications for advocacy of sun protection and sunscreen use. J Invest Dermatol 98:809–11 | Article | PubMed | ChemPort |
