Vitamin D status in healthy free living elderly men and women living in Canada

  Several epidemiological studies and clinical trials have linked vitamin D status to hypertension, Type II diabetes and cardiovascular disease. Vitamin D is also believed to have an immunomodulatory effect and is linked to type I diabetes. In addition, vitamin D is associated with breast, colon and prostate cancer. The prevalence and correlates of vitamin D deficiency in healthy elderly living in countries at high latitude is not well known, our objective was to determine the distribution of serum 25(OH)D concentrations in healthy elderly Canadians and determine how season, age, sex, adiposity, physical activity level and supplement consumption affect this distribution. Men and women in age groups 68 - 72, 73 - 77 and 78 - 82 years in two seasons, participating in the NuAge cohort were examined (n=405). Serum 25(OH)D was assessed by radioimmunoassay (RIA), weight, height, smoking status, medication, disease status, education, perception of income, Physical Activity Scale for the Elderly questionnaire (PASE) and vitamin D supplement consumption were assessed. The prevalence of vitamin D deficiency (25(OH)D < 37.5 nmol/L) was 12.6 % and 5.7% for men in winter and summer, and 8.7 % and 1.9 % for women in the two seasons respectively. Over 50 % had 25(OH)D concentrations < 75 nmol/L. Correlates of Vitamin D status by multiple regression analysis indicated that the vitamin D level in summer was 13.8 nmol/L higher than in winter and 17.2 nmol/L higher for those using supplements. Age, sex, body mass index, and PASE were not associated with 25(OH)D concentration. In conclusion, prevalence of vitamin D deficiency is low in healthy elderly men and women, especially in summer, but over 50% of the participants had sub-optimal vitamin D concentrations. Vitamin D supplement consumption increased 25(OH)D concentrations substantially, particularly in the winter months and should be encouraged to prevent chronic disease.