Socio-economic determinants of vitamin D deficiency in the older Polish population : results from the PolSenior study

ObjectiveNumerous 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.DesignCross-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.SettingCommunity-dwelling randomly selected individuals aged 65 years or older, selected using three-stage stratified, proportional draw.SubjectsSeniors (n 3472; 1658 women and 1814 men).ResultsMean 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.ConclusionsVitamin D deficiency/insufficiency is frequent in the older Polish population and associated with functional disability and impaired mobility of seniors.