Decreased bone density in severely handicapped children and adults, with reference to the influence of limited mobility and anticonvulsant medication

Abstract

Bone density and related biochemical parameters were investigated in institutionalised children and adults with severe handicaps, who were classified according to the degree of limited mobility (group 1, bed-ridden; group 2, capable of crawling; group 3, capable of walking) and according to whether or not they were receiving anticonvulsants. As determined by microdensitometric analysis of radiograms of the second metacarpal bone, bone width (D), bone pattern area (sigma GS) and bone salt density (sigma GS/D) were decreased in the patients, the decreases being most prominent in group 1, followed by groups 2 and 3, in that order. Significant decreases of sigma GS and sigma GS/D, but not of D, were found in patients on anticonvulsant treatment in comparison to patients without therapy. Serum alkaline phosphatase (Al-p) and parathyroid hormone (iPTH) as well as urinary calcium and cyclic adenosine-3',5'-monophosphate (cAMP) excretion were significantly increased in group 1. In comparison to patients without therapy, anticonvulsant-treated children showed significantly decreased levels of serum calcium (Ca), ionised Ca (Ca2+), 25-hydroxy vitamin D3 and urinary phosphate (PO4) excretion, and elevated levels of Al-p, iPTH and calcitonin (iCT). It is suggested that limited physical activity results in a mild hyperparathyroid state, which is aggravated in patients on anticonvulsant treatment.

Bone mineral status after pediatric spinal cord injury

“…25 It has been reported that the development of bone mass in patients with pediatric SCI never reaches normal levels, which exposes these patients to fractures. 1,36 In the present study the BMD in the lumbar spine reached the level of the general reference population, which shows that at least the mineralisation of central bone returns to normal levels in adolescents with pediatric SCI after initial phases of SCI. The amount of bone mineral loss at hip level was shown to remain at alarmingly low values.…”

Bone mineral content of the lumbar spine and lower extremities years after spinal cord lesion

“…In the present study three of the participants with fractures had sustained their spinal cord injury in childhood when the bone mass was not fully developed and thus never reached a normal level (Nishiyama et al, 1986).…”

Prevalence of reduced bone mass in children and adults with spastic quadriplegia

“…In a series of 118 Japanese children and adults with severe disabilities, Nishiyama and coworkers found that bone density, as assessed by metacarpal bone density, was lower in non-ambulatory patients compared with those who could walk or crawl. Serum 25-OH vitamin D levels were lower in those receiving anticonvulsants; however, most were receiving either phenobarbital or diphenylhydantoin (Nishiyama et al 1986). Two agents, phenobarbital and diphenylhydantoin, have been specifically linked to the effect on serum 25-OH vitamin D by stimulation of the P450 mixed oxidase pathways, thereby metabolizing 25-OH vitamin D to more polar metabolites (Hahn et al 1975).…”