Women with ovarian cancer and control subjects were analyzed for their vitamin D status as measured by serum 25(OH)D3 level in 7,243 women from the National Health and Nutrition Examination Surveys (NHANES).
A high and low status of levels of serum vitamin D was defined as above or below 23 ng/mL (57.5 nmol/L). After adjusting for age, diet and body mass index, ovarian cancer cases were over three times as likely to have inadequate 25(OH)D3 levels compared with the controls.
Previous research has shown that vitamin D induces apoptosis in ovarian CA cell lines, ovarian cancer has been inhibited by vitamin D in animal studies and although studies are mixed–ovarian cancer rates appear to be higher in areas with less sun exposure.
Other research on vitamin D consistently observes that a long list of chronic diseases and cancers are associated with lower vitamin D status, with some showing risk reduction when levels are above 30 ng/mL, 40 ng/mL and even 50 ng/mL. Despite this large and growing body of evidence, the Institute of Medicine recently released its Dietary Reference Intakes for Calcium and Vitamin D based on a target level of 20 ng/mL and randomized controlled trials, rather than the cornucopia of observational studies. This resulted in recommended doses of 600-800 I.U. per day depending on age. As I stated in a January blog, it is too bad… that these observational studies were not considered, and once again, we may not have optimal prevention and risk reduction guidelines from our government agencies. Many if not most alternative minded practitioners are recommending a routine dosing of 2,000 I.U. of vitamin D per day, in individuals who do not have a history of kidney stones nor elevated serum calcium levels. However, most women will achieve a minimum serum level of 23 ng/mL (as stated in this current ovarian cancer prevention study) at doses of 600 I.U.-1,000 I.U. per day. A simple blood test will confirm. This would be a logical step in women with risk factors for ovarian cancer or a personal history of ovarian cancer.
Reference: Bakhru A, Mallinger JB, Buckanovich RJ, Griggs JJ. Casting light on 25-hydroxyvitamin D deficiency in ovarian cancer: a study from the NHANES. Gynecol Oncol 2010;119:314-8.