Vitamin D status in inpatients admitted to an internal medicine department

A role of hypovitaminosis D has been advocated in several medical conditions. We investigated vitamin D status in medical inpatients, compared to a blood donors' group from the same area.

Fifty-nine consecutive medical patients were recruited at hospital admission, concomitantly to 207 blood donors of both genders. Serum calcium, albumin, phosphate, creatinine, alkaline phosphatase total activity, 25-hydroxyvitamin D [25(OH)D] and parathyroid hormone (PTH) were assessed from April to May 2005.

In patients, 25(OH)D values were lower (13.1 +/- 9.2 vs. 16.3 +/- 8.5 ng/ml; p < 0.02) and PTH values higher (73.9 +/- 77.7 vs. 53.4 +/- 24.3 pg/ml; p < 0.01) than in controls, whose mean age was lower (62.5 +/- 14.5 vs. 45.8 +/- 15.6 years, p < 0.01). Such differences were not confirmed when comparing patients to a subgroup of age and sex-matched controls drawn from the whole sample of blood donors. In both patients and controls there was a trend towards a negative correlation between 25(OH)D and age and a positive correlation between PTH and age. The prevalence of 25(OH)D <12 ng/ml was higher in patients than in controls as a whole (58 vs. 34%; chi(2) = 9.95; p < 0.002), but not in respect to the subgroup of matched controls (58 vs. 44%; chi(2) = 2.09; p = 0.14). The prevalence of severe vitamin D deficiency, 25(OH)D <5 ng/ml, was significantly higher in patients than in matched controls (17 vs. 4%; chi(2) = 6.75; p < 0.01).

Hypovitaminosis D, defined as 25(OH)D <12 ng/ml, is frequent among inpatients, as in the general population of comparable age. A severe vitamin D deficiency is more common in hospitalized patients.