High prevalence of hypovitaminosis D and secondary hyperparathyroidism in elders living in nonprofit homes in South Brazil

Objectives Hypovitaminosis D (HD) and secondary hyperparathyroidism (SHP) are common in elders, and many factors could contribute to them. The objectives of this study were to estimate the prevalence of HD, SHP, and its associated factors, in individuals living in nonprofit homes for elders in south Brazil. Design Cross-sectional study. Methods Serum 25-hydroxyvitamin D 25(OH)D, intact parathyroid hormone (PTH), total calcium, phosphorus, alkaline phosphatase, magnesium, creatinine, and albumin levels were measured in late spring, November, 2005. The presence of factors potentially related with HD and SHP-age, sex, weight, height, skin phototype, sun exposure, exercise, smoking, use of <= 5 medications or diuretics or alcohol, and daily calcium ingestion. Results 102 subjects age 77.8 +/- 9.0 were included in the study. HD was found in 85.7% and SHP in 53% of the subjects. The estimated daily calcium ingestion was 720 mg. There was no association between serum 25(OH)D levels and any of the risk factors evaluated. Serum 25(OH)D levels were correlated with serum PTH (r = -0.358, P = 0.000), calcium (r = 0.306, P = 0.002), and albumin (r = 0.253, P = 0.011) levels. In univariate analysis, SHP was positively associated with age (P = 0.006), and female sex (0.007); and negatively associated with sunlight exposure (P = 0.020), GFR (P = 0.000), Ln25(OH)D (P = 0.002), and total serum calcium (P = 0.024). After multivariate model adjustment, age [OR 1.09 (CI 1.01-1.18); P = 0.024], Ln25(OH)D [OR 0.92 (CI 0.08-0.74); P = 0.013], GFR [OR 0.96 (CI 0.92-0.99); P = 0.013], and hydrochlorothiazide treatment [OR 7.63 (CI 1.67-34.9); P = 0.008] were independently associated with SHP. Conclusions HD and SHP are highly prevalent in elders living in old-age homes. No associations were established between common risk factors and low serum levels of 25(OH)D levels; however, SHP was independently related with age, 25(OH)D, GFR, and hydrochlorothiazide use.