Bone Mineral Density in Subjects with Cerebral Palsy: A Preliminary Study in Taiwan

Abstract

Objective: Children with cerebral palsy (CP) have complicated disabilities, and also have the tendency to suffer from osteoporotic fractures. The aim of this study was to explore the bone mineral density (BMD) and to estimate the fracture rate in Taiwanese CP subjects. Materials and methods: To study the BMD and its related factors in 28 Taiwanese CP subjects (16 males, 12 females; age range, 2-24 years; mean age, 9.8 years), we evaluated their BMD in the lumbar spine (LS-BMD) with dual energy x-ray absorptiometry, clinical characteristics, biochemical bone metabolism-related factors, and nutritional status. The fracture rate was evaluated during a three-year follow-up. Statistical comparisons were made using the Student’s t test and correlation analyses. Results: In our study, we found that CP subjects had significantly reduced LS-BMD z score (mean ± standard deviation, -2.46±1.06), especially in those who were bedridden (-3.28±0.99, vs. the ambulatory group, p＜0.005; vs. the wheelchair group, p＜0.05), quadriplegic (-2.89±1.24, p＜0.05) and older than 10 years of age (-3.12±1.12, p＜0.01); that for wheelchair-dependent ones, the z score was correlated positively with the deficiency of daily caloric intake (r=0.79, p＜0.01) and negatively with the serum albumin level (r=-0.68, p＜0.05); that for bedridden ones, the z score and the body weight fraction were positively correlated (r=0.77, p＜0.05); that two subjects had new femoral fractures during a three-year follow-up; and that the fracture rate was 2.4 per 100 person-years. Conclusion: The CP subjects have significantly reduced LS-BMD z score, especially in those who have been bedridden, quadriplegic and older than 10 years of age. The BMD measured in the lumbar spine may not be an ideal predictor for the risk of femoral fracture found in CP subjects.