Correlation between sarcopenia and osteoporosis in patients with post-poliomyelitis syndrome

Abstract

Muscle mass, -strength and -density, sarcopenia, exercise and physical activity are correlated with bone mass, bone density and osteoporotic fractures. Bone and muscle decay and dysfunction are seen in ageing, but in neurological disorders with muscular atrophy, bone loss can be seen also at younger ages. Femoral neck and lumbar spine bone mineral density (BMD) is measured using dual X-ray absorptiometry in 30 patients with post-poliomyelitis syndrome, 18 women and 12 men, with a mean age of 56.3 years (ranging from 37 till 70). Eight women were postmenopausal. Mean femoral neck BMD was −22.76% or −1.86 SD and mean lumbar BMD was −13.21% or −1.25 SD. Low femoral bone mass was found in 80% of the patients (12 men and 12 women, of whom 5 were post-menopausal) and low lumbar bone mass was seen in 63% (9 men and 10 women, of whom 8 were post-menopausal). Six patients (all women) had normal femoral BMD and 11 normal lumbar BMD, whereas 6 (3 male and 3 female) had osteoporotic femoral BMD-scores (< −2.5 SD) and 3 (1 man and 2 women) had osteoporotic lumbar BMD. The remaining patients had osteopenia: 18 showed femoral osteopenia (< −1 SD) and 16 lumbar osteopenia. A significant difference in femoral (cortical) BMD between men and women was found: −27.72% or −2.24 SD in men and −19.46% or −1.62 SD in women. Only small sex differences were seen in lumbar (trabecular) BMD: −13.85% or −1.37 SD in men and −12.78% or −1.17 SD in women. The lowest BMD scores were present in patients with visible and clear lower limb muscle atrophy. A correlation is shown between low muscle mass and low cortical BMD can be explained by neurogenic bone loss, both due to muscle atrophy and disturbed regulation of bone by the central nervous system.