According to a study published in September 2012, serum vitamin D levels are associated with reduced mortality from lung cancer, and this relationship is modified by serum vitamin A levels. The Centers for Disease Control and Prevention (CDC) state that lung cancer is the leading cause of cancer death and the second most diagnosed cancer in both men and women in the U.S. Approximately 28 percent of all cancer deaths are due to lung cancer.
The researchers evaluated 16,693 men and women in the Third National Health and Nutrition Examination Survey 1988-1994. Mortality from lung cancer was assessed using the National Death Index through 2006. The investigators assessed serum 25-hydroxyvitamin D and markers of vitamin A including serum retinol, beta-carotene and retinyl esters. The subjects also completed questionnaires regarding supplement intake in the prior month.
The researchers found no correlation between serum vitamin D and overall lung cancer mortality. However, the researchers determined that among non-smokers, serum 25-hydroxyvitamin D levels of 44 nmol/L or greater reduced the risk of lung cancer mortality by 47 percent compared to nonsmokers with serum 25-hydroxyvitamin D of less than 44 nmol/L.
In people who never smoked or smoked quite a long time ago, 25-hydroxyvitamin levels of 44 nmol/L or greater reduced the likelihood of lung cancer mortality by 69 percent compared to those in the same group with a 25-hydroxyvitamin D level of less than 44 nmol/L. Interestingly, the researchers found that these associations did not hold among the subjects with excess circulating vitamin A, determined as serum retinyl esters of 7.0 μg/dL or greater or among vitamin A/beta-carotene supplement users.
The researchers concluded, “Serum 25-hydroxyvitamin D concentrations were inversely associated with lung cancer mortality in nonsmokers. The beneficial association was diminished among those with excess circulating vitamin A or vitamin A/beta-carotene supplement users.”
Cheng TY, et al. Cancer Causes Control. 2012 Sep;23(9):1557-65.