Numerous studies have reported an association between vitamin D (25-hydroxyvitamin D; 25(OH)D) deficiency and low economic status, lower educational level, drugs exposure, smoking and reduced physical activity. Our study analysed the association between sociodemographic factors and 25(OH)D status in Polish (Caucasian) seniors.

Cross-sectional study (part of the PolSenior study). Serum 25(OH)D concentration was measured by a solid-phase ELISA method; a standardized questionnaire evaluated educational level, economic status, alcohol consumption, current or past cigarette smoking, physical activity, activities of daily living (ADL) and instrumental activities of daily living.

Community-dwelling randomly selected individuals aged 65 years or older, selected using three-stage stratified, proportional draw.

Seniors (n 3472; 1658 women and 1814 men).

Mean serum 25(OH)D concentration was 20·5 (sd 9·6) ng/ml. Values below the recommended level (30 ng/ml) were detected in 82·8 % of men and 90·4 % of women. Regression analysis revealed that the difference between sexes was associated with decreased walking activity in women, probably resulting in less sunlight exposure. There was a positive association between any disability in ADL and the presence of vitamin D deficiency/insufficiency. In the sex-adjusted analysis, older age, alcohol abstinence and lack of cycling and long-distance walking were explanatory variables for vitamin D deficiency.

Vitamin D deficiency/insufficiency is frequent in the older Polish population and associated with functional disability and impaired mobility of seniors.