Changes in muscle mass, fat mass, and bone mineral content in the legs after stroke: a 1 year prospective study

Demineralization and muscle atrophy, common among patients with hemiplegia, may be risk factors for future hip fracture. The aim of this longitudinal study was to investigate changes in lean (muscle) mass and bone mineral content (BMC) of the legs during the first year after stroke according to the patient’s ambulatory level. Twenty-five patients immobilized due to acute stroke were followed. BMC and lean mass of each leg were measured at a mean of 7 days, 2 months, 7 months, and 1 year after the stroke using dual-energy X-ray absorptiometry. Both BMC and lean mass had decreased significantly in the paretic leg (p< 0.05) at the 1 year evaluation and the loss was significantly greater on the paretic side compared with the nonparetic side (p< 0.001). Patients who had not relearned to walk at the 2 month evaluation (n = 12) lost 6% (p< 0.05) of their lean mass in the paretic leg during this time period, and this mass was not regained within the subsequent 10 months. In contrast, a significant 5% loss of lean mass found at 2 months on the nonparetic side was regained completely. With respect to the patients who relearned to walk within the first 2 months (n = 13) lean mass had increased by 5% after 1 year (p< 0.05) in the nonparetic leg, whereas no significant changes were found in the paretic leg during follow-up. Both groups of patients did, however, lose bone mineral in the paretic leg during the first year after stroke (9% and 6%, respectively, p< 0.05), but only the patients who were still unable to walk by 2 months had significant bone loss in the nonparetic leg also (3%, p< 0.05). Thus, lean muscle mass is rapidly lost and may be regained shortly after stroke, whereas loss of BMC appears difficult to prevent, especially on the paretic side. Regaining muscle mass may, however, slow the loss of bone mineral.