Life-style factors associated with winter serum 25-hydroxyvitamin D levels in elderly adults.

A cross-sectional survey of community-dwelling elderly volunteers (104 women, 87 men, mean age 70 years) was carried out in winter to determine whether cardiovascular and other potentially modifiable lifestyle factors were associated with serum levels of 25-hydroxyvitamin D during this period. Mean winter levels of serum 25-hydroxyvitamin D were higher in men than in women (14.2 vs. 12.2 ng/ml, p = 0.021), higher in those who used margarine daily compared with less often (14.4 vs. 11.9 ng/ml, p = 0.005), and higher in those who holidayed overseas in the last 6 months at a lower latitude than in Great Britain or Germany (14.9 vs. 12.4 ng/ml, p = 0.044), after controlling for other confounders. Serum 25-hydroxyvitamin D levels were not related to the number of hours spent outdoors during the previous month (r = 0.04, p > 0.05). When participants were classified by tertile of low-density lipoprotein (LDL) cholesterol, mean serum 25-hydroxyvitamin D was raised in the highest (14.3 ng/ml, p = 0.011) and middle (13.3 ng/ml, p = 0.15) tertiles compared with the lowest tertile (11.9 ng/ml), after controlling for other confounders. All other cardiovascular risk factors, including total- and HDL-cholesterol, blood pressure, BMI, smoking and leisure physical activity, were unrelated to serum vitamin D. These results suggest that body vitamin D levels in elderly people during winter are related to diet and overseas holidays within the last 6 months, but not to UK winter sun exposure, nor to the major cardiovascular risk factors apart from LDL cholesterol.