Functional status of the paretic arm affects the loss of bone mineral in the proximal humerus after stroke: A 1-year prospective study

The aim of this study was to evaluate the effect of decreased arm function after stroke on bone mineral density (BMD) in the proximal humerus. Twenty- five patients were evaluated 1 week after acute stroke and reevaluated 2 mo nths, 7 months, and 1 year after the stroke. BMD of the proximal humerus wa s measured and the functional status of the paretic arm was assessed., With in 1 year the BMD decreased significantly in the proximal humerus at the pa retic side. No significant BMD change was found at the nonparetic side. Pat ients with an initial completely paralyzed arm lost 27% (P < 0.001), those with severe to moderate paresis lost 11% (P < 0.001), and patients with min or or no paresis had no significant bone loss in the proximal humerus at th e paretic side after 1 year. A statistically significant trend with initial arm function was found both 7 months and I year after the stroke at the pa retic side (P < 0.01). Patients who were paralyzed or had severe to moderat e paresis both at inclusion and after 1 year had a larger I-year bone loss in the proximal humerus than the patients who recovered and these who had o nly minor impairment throughout the study, 25%, 8%, and 5%, respectively (P -value for linear trend <0.001). We conclude that during the first year aft er stroke bone mineral is lost in the proximal humerus of the paretic arm, but that the loss depends on the initial degree of paresis. The loss may be prevented if arm function is regained.