1: Neurology. 1997 Nov;49(5):1273-8.

High prevalence of vitamin D deficiency and reduced bone mass in Parkinson's
disease.

Sato Y, Kikuyama M, Oizumi K.

Department of Neurology, Futase Social Insurance Hospital, Iizuka, Japan.

Despite excessive hip fractures in patients with Parkinson's disease (PD),
little is known about bone changes in these patients. We measured bone mineral
density (BMD; Z scores) in PD patients and analyzed its relation to serum
biochemical indices and sunlight exposure. We measured BMD in 71 patients in the
second metacarpals and divided the patients into two groups according to
functional independence; group 1, Hoehn and Yahr stages 1 and 2; and group 2,
stages 3 to 5. In four of 20 patients in group 1 (20%), the Z score was less
than -1.0, indicating osteopenia. In 51 patients in group 2, 31 (61%) had a Z
score less than -1.0. The group 1 patients showed a normal mean serum level of
25-hydroxyvitamin D (25-OHD; 21.7 ng/ml), while most group 2 patients were in a
deficiency range (group mean 8.9 ng/ml). Many group 2 patients were sunlight
deprived. Both groups had elevated serum ionized calcium levels correlating
positively with Hoehn and Yahr stage and markedly depressed serum
1,25-dihydroxyvitamin D (1,25-[OH]2D) concentrations, indicating that
immobilization-induced hypercalcemia had inhibited 1,25-[OH]2D production. Z
scores correlated positively with 25-OHD levels and negatively with parathyroid
hormone concentration and Hoehn and Yahr stage. Vitamin D deficiency due to
sunlight deprivation and hypercalcemia induces compensatory hyperparathyroidism,
which contributes to reduced BMD in PD patients, particularly those who are
functionally dependent. Low BMD increases risk of hip fractures in patients with
PD but may be improved by vitamin D supplementation.

PMID: 9371907 [PubMed - indexed for MEDLINE]