Background: Hypovitaminosis D is an important risk factor for osteoporosis and its complications. Previous studies found that the incidence of hypovitaminosis D among patients in an internal medicine ward reached up to 57%.

Objectives: To determine the prevalence and determinants of hypovitaminosis D among patients in internal medicine wards in a sunny country.

Methods: We measured 25-hydroxyvitamin D, parathyroid hormone and various other laboratory parameters, and assessed the amount of sun exposure, dietary vitamin D intake and other risk factors for hypovitaminosis D in 296 internal medicine inpatients admitted consecutively to the Soroka University Medical Center, which is situated in a sunny region of Israel.

Results: We found hypovitaminosis D (serum 25-HO-D[1] <15 ng/ml) in 77 inpatients (26.27%). The amount of sunlight exposure, serum albumin concentration, being housebound or resident of a nursing home, vitamin D intake, ethnic group, cerebrovascular accident and glucocorticoid therapy were all significantly associated with hypovitaminosis D. Multivariate analysis showed a significant association between hypovitaminosis D and Bedouin origin, sun exposure, vitamin D intake, and stroke. Hypovitaminosis D was also found among inpatients who reported consuming more than the recommended daily amount of vitamin D. Parathyroid hormone levels were significantly higher in patients with 25-OH-D levels below 15 ng/ml. In a subgroup of 74 inpatients under 65 years old with no known risk factors for hypovitaminosis D, we found 20.3% with hypovitaminosis D.

Conclusions: Hypovitaminosis D is common in patients hospitalized in internal medicine wards in our region, including patients with no known risk factors for this condition. Based on our findings, we recommend vitamin D supplementation during hospitalization and upon discharge from general internal medicine wards as a primary or secondary preventive measure.