Vitamin D Levels and Seasonal Changes in Elderly Cretans, Men and Women

Background: Low serum 25-hydroxyvitamin D [s25(OH)D] levels have been reported in a high proportion of institutionalized or home bound subjects and also in ambulatory elderly people with limited exposure to sunlight due to geographical location. Aim of this study is to investigate the s25(OH)D status as well as its seasonal variation in ambulatory elderly people permanent inhabitants of Crete, the southernmost island of Europe. Subjects and Methods: 101 ambulatory subjects, selected after applying strict exclusion criteria, from the Centres of Open Care for the Elderly, of Heraklion-Crete, 70 women and 31 men, (70,00±5,00 years and 73,00±5,49 respectively) Serum 25(OH)D, serum parathormone (sPTH), Ca, P, Cre, BMI and grade of mobility were assessed. In a subgroup of 25 subjects, s25(OH)D and sPTH were evaluated twice (winter and summer). Results: Mean s25(OH)D was 51,46±27,32 nmol/L in women and 71,7±28,65 nmol/L in men. Levels = 30nmol/L were found to 10% of men and 30% of women whereas levels = 50nmol/L were found to 29% of men and 53,6% of women. Mean sPTH was 59,77±28,92 pg/ml in women and 63,91±24,82 in men Subjects with mobility A had higher levels of s25(OH)D than subjects with mobility B (t(99)=3,612 p=0,000) and summer levels of s25(OH)D were higher than the winter ones (p<0,001) whereas summer levels of sPTH were lower (p=0,007). Conclusion: Despite of the geographic location of Crete, and the ?editerranean diet followed, there is a high prevalence of vitamin D deficiency among ambulatory community dwelling elderly, being much higher in women, which can be attributed to the inadequate exposure to sunlight and to the lack of foods fortified with vitamin D and/or the supplementation of Vitamin D.