Abstract A120: Physical activity, body mass index, and vitamin D metabolite concentrations

Abstract

Abstract Serum 25(OH)D concentrations have been demonstrated to be inversely related to several cancers. Because vitamin D can be obtained from both dietary sources and endogenous synthesis, the best strategy for improving vitamin D status is unclear, though abbreviated sun exposure, supplementation, and fortification have been suggested. Both physical activity and body mass index (BMI) have been shown to be correlated with 25(OH)D concentrations and themselves have been linked to colorectal neoplasia. We sought to investigate the types of physical activity that contribute most to circulating concentrations of vitamin D metabolites in a study population in southern Arizona, and to further evaluate the relative contributions BMI and type of physical activity to 25(OH)D concentrations. Individuals in the highest category of recreational physical activity were significantly more likely to have 25(OH)D concentrations of >=30 ng/ml as compared to those who were less active (p=0.007). After adjustment for BMI, age, race, sex, and season of blood draw, recreational physical activity remained statistically significantly associated with serum concentrations of 25(OH)D (p= 0.002), while household and sedentary physical activity were not related in either crude or adjusted models. For those participants with a normal BMI (18 < BMI <25), recreational physical activity had no influence on circulating concentrations of 25(OH)D (p=0.28); however, for those who were overweight (25<BMI<30) or obese (BMI >=30), recreational physical activity was directly associated with 25(OH)D levels (p=0.002 and p=0.009, respectively). For example, among obese participants, those in the lowest tertile of physical activity had a mean (+sd) 25(OH)D concentration of 22.4 + 7.8, while those in the highest tertile had levels of 27.0 + 7.2 (p-trend=0.009), possibly due to increased sun exposure. These results suggest that overweight individuals may be able to improve vitamin D status via recreational physical activity, which may in turn reduce the risk of several cancers. Citation Information: Cancer Prev Res 2010;3(1 Suppl):A120.