A Study of Bone Mineral Density in Adults With Disability

Abstract 

Smith ÉM, Comiskey CM, Carroll ÁM. A study of bone mineral density in adults with disability.

Objectives

To examine prevalence of low bone mineral density (BMD) among adults with disability, using World Health Organization diagnostic categories.

Design

Cross-sectional study.

Setting

National Rehabilitation Hospital, Dublin, Ireland.

Participants

Patients (N=255; 178 men, 77 women) who were disabled for at least 3 months because of acquired brain injury, spinal cord injury, other neurologic condition, or lower-limb amputation.

Interventions

None.

Main Outcome Measures

Laboratory investigations including intact parathyroid hormone, 25-hydroxyvitamin D (25-OHD), and sex hormones; and BMD of lumbar spine and at least 1 hip, measured by dual-energy x-ray absorptiometry and expressed as T scores and z scores.

Results

Mean age ± SD of participants was 48.7±15.6 years. Vitamin D deficiency, 25-OHD level 50nmol/L or less, occurred in 154 (62.9%); insufficiency, a level between 51 and 72nmol/L, occurred in 36 (14.7%). Based on T scores, 108 participants (42.4%) had osteopenia, and 60 (23.5%) had osteoporosis. A z score of −1 or less but more than −2 occurred in 76 (29.8%); a further 52 (20.4%) had a z score of −2 or less. On multiple linear regression analysis, ambulatory status and duration of disability were independent predictors of BMD at neck of femur (β=.152, P=.007; β=−.191, P=.001, respectively) and total proximal femur (β=.170, P=.001; β=−.216, P<.001, respectively).

Conclusions

Osteopenia and osteoporosis are very common in adults with disability participating in rehabilitation, compared with the general young adult population. Duration since onset of disability and mobility status are independent predictors of BMD at the hip. Bone health monitoring should form part of the long-term follow-up in adults with newly acquired disabilities.

Key Words: Bone density, Disabled persons, Osteoporosis, Rehabilitation

List of Abbreviations: ANOVA, analysis of variance, BMD, bone mineral density, DXA, dual-energy x-ray absorptiometry, iPTH, intact parathyroid hormone, ISCD, International Society for Clinical Densitometry, QC, quality control, SCI, spinal cord injury, 25-OHD, 25-hydroxyvitamin D, WHO, World Health Organization