Objectives. To study the vitamin D levels in the period of minimal sun exposure in individuals older than 50 years residing in the Republic of Bashkortostan. Materials and methods. In the period of low insolation (March) in 188 people (68 men and 120 women) aged over 50 years (mean age 66,1 ± 0,75 years) residing in the city (Ufa) and rural areas of the Republic of Bashkortostan we investigated the levels of 25 (OH) D and parathyroid hormone (PTH) by the indirect ELISA. Level of 25 (OH) D 25-50 nmol/l were considered as mild vitamin D deficiency; 12,5-25 nmol/l-as moderate deficiency, and levels below 12.5 nmol/l - as a severe vitamin D deficiency. Results. The average level of 25 (OH) D was 33,55 ± 1,28 nmol/l; in urban area 43,48 ± 1,59 nmol/l; in rural area 21,25 ± 1,06 nmol/l; 36,29±2,43 nmol/l in men; 32,28± 1,47 nmol/l in women. The levels of vitamin D in the urban population were twice as high as in rural areas. A statistically significant difference by gender in terms of the levels of vitamin D was not found. We saw normal levels of vitamin D only in 18 % of subjects (in the city- 30 %, in the rural areas - 2 %), 43 % of people had a mild vitamin D deficiency (in the city - 59 %, in rural areas - 24 %), 33 % - a moderate deficiency of vitamin D (in the city -11 %, in the rural areas - 60 %), and 6 % of the patients had a severe vitamin D deficiency (in the city - 0 %, in rural areas -14 %). Moderate to severe vitamin D deficiency in rural areas was significantly more prevalent (74 %) than in urban (11 %). Gender was not found to be a risk factor for the development of vitamin D deficit in people over 50 years. There was a negative correlation between vitamin D levels and patient age (r=-0,356, p <0,001) and between levels of vitamin D andPTH (r =-0,313, p <0.001).

vitamin D, parathyroid hormone.