Serum 25-hydroxyvitamin D concentration among users of a referral outpatient unit for vascular diseases and associated factors.

Abstract

Assess serum 25-hydroxyvitamin D (25OHD) concentration and associated factors among users of a referral outpatient unit for vascular diseases in Southern Brazil. Cross-sectional study conducted for almost one year, from March 2016 to January 2017. The serum vitamin D level was determined biochemically and classified as: sufficient (>50nmol/L), insufficient (30-50nmol/L) and deficient (<30nmol/L). Associations were tested through multiple linear regression. At a reference outpatient clinic specialized in vascular diseases located in a southern Brazilian medium-sized city (latitude 29°S). Consecutive sample of 133 individuals of both sexes, aged at least 40 years. The mean serum 25OHD concentration was 54.9±25.9nmol/L (57.7±27.9nmol/L for men; 52.2±24.2nmol/L for women, p=0.267). A total of 12.8% of the participants had vitamin D deficiency and 32.3% had insufficiency. Regarding the total sample, variables associated to the serum 25OHD concentration were: age (β=-0.55; CI95%-0.95;-0.17), sun exposure (β=1.22; CI95% 0.32; 2.10) and vitamin D intake (β=7.29; CI95% 2.10; 12.48). Among men, a significant association was observed for age (β=-0.82; CI95%-1.47;-0.17, p=0.015) and borderline for sun exposure (β=1.22; CI95% 0.32; 2.10, p=0.053). Among women, only vitamin D intake was significantly associated with serum concentration of this vitamin (β=8.74; CI95% 1.32; 16.17, p=0.022). Although the mean 25OHD concentration was greater than 50nmol/L, about 45% of this consecutive sample presented poor vitamin D nutritional status. Unadjusted for seasonality, factors associated with serum 25OHD concentration were age and sun exposure among men and vitamin D intake among women.