Densitometric and quantitative ultrasound measurements and laboratory investigations in wheelchair-bound patients.

Skeletal status and laboratory investigations may be influenced by immobilization. Thirty-six wheelchair-bound subjects and 19 age-matched controls were evaluated using measurements of bone mineral density (BMD) at the calcaneus and forearm (PIXI, Madison, WI), amplitude-dependent speed of sound at the hand phalanges (quantitative ultrasound-DBM Sonic 1200, IGEA, Modena, Italy), carboxyterminal telopeptide of type I collagen and bone alkaline phosphatase. In the whole group and in the males, bone mineral density values were significantly lower in comparison with controls (calcaneus, forearm) and in females only for calcaneus. The duration of the disease significantly influenced the calcaneal bone mineral density data. Bone alkaline phosphatase was significantly lower in the patients than in the controls. Bone resorption had a negative influence on forearm BMD. Generally, skeletal and laboratory results were not affected by duration of the disease or reason for immobilization. In conclusion, in wheelchair-bound subjects, the skeletal status was affected and bone formation was depressed.