MILD VITAMIN-D DEFICIENCY AND SECONDARY HYPERPARATHYROIDISM IN NURSING-HOME PATIENTS RECEIVING ADEQUATE DIETARY VITAMIN-D

Objective: To compare the vitamin D metabolite and nutritional status of institutionalized elderly males with a non-institutionalized control group. Design: Case-control study. Setting: Veterans Administration Medical Center Nursing Home (NH) in Richmond, Virginia. Patients: Fifty-seven consecutive nursing home subjects were screened. After excluding blacks, those receiving anticonvulsants, glucocorticoids, or vitamin supplements, and those with liver or renal failure (creatinine > 1.5 mg/dL), 35 subjects were enrolled, and 22 completed the study. The non-institutionalized control group (n = 18) consisted of consecutive volunteers, meeting the above criteria, from either a senior citizen group or a geriatric clinic. Measurements and Main Results: The serum 25-hydroxyvitamin D level in the NH residents was significantly lower than in community dwellers (17.4 +/- 5.2 ng/mL vs 31.2 pg/mL +/- 8.0 ng/mL, P < 0.0001). No significant difference was demonstrated in 1,25-dihydroxyvitamin D levels (36.5 pg/mL +/- 10.5 in NH residents vs 42.0 pg/mL +/- 11.1 in controls). In the NH group PTH levels were inversely correlated with 25 OHD levels (P < 0.008) and positively correlated with length of stay in the NH (P < 0.016). There was no significant seasonal variation in vitamin D metabolite levels in the NH group. In the NH patients, the mean dietary intake of vitamin D was 232 +/- 378 mg/day and of calories was 1811 +/- 447 kcal/day. Conclusion: Despite apparently adequate calories, calcium, and vitamin D intake, hypovitaminosis D with compensatory PTH elevations occurs, regardless of season, in the nursing home population.