Hypovitaminosis D and decreased bone mineral density in amyotrophic lateral sclerosis

To assess the bone health of patients with amyotrophic lateral sclerosis (ALS), we evaluated the bone density and serum biochemical indices of bone metabolism in 11 ALS patients. The serum concentration of 25-hydroxyvitamin D (25-OHD) was significantly lower in patients (14.0 +/- 3.7 ng/ml) than in controls (25.2 +/- 4.0 ng/ml), at deficient levels (< 10 ng/ml) in 2, and at insufficient levels (10-20 ng/ml) in 9 patients. Serum levels of parathyroid hormone (PTH) and ionized calcium were elevated in 8 and 6 patients, respectively. Dietary intake of vitamin D was below the recommended level (100 IU) in 10 patients, and 10 patients were in a sunlight-deprived state. The metacarpal bone density (MBD) and the metacarpal index (MCI) of the second metacarpal bone were measured by computed X-ray densitometry. Z scores of the MBD and the MCI were negative in 7 and 6 patients, respectively. The serum concentration of 25-OHD was positively correlated with the Z score of the MBD (p < 0.05, r = 0.727) and negatively with the PTH level (p < 0.05, r = -0.410). The degree of dysfunction of hand grip also correlated with the Z score of the MBD (p < 0.05, r = 0.749). These data underscore the importance of hypovitaminosis D and compensatory hyperparathyroidism in the development of osteopenia in patients with ALS.