Objective: Measure central bone mineral density (BMD) in community-dwelling individuals with intellectual and/or developmental disabilities.
Design: A cross-sectional study.
Setting: A regional center providing outpatient medical, residential, and day activity services for individuals with intellectual and/or developmental disabilities.
Participants: Documented BMD results were obtained for 298 community-dwelling individuals with intellectual and/or developmental disabilities.
Measurements: BMD by central dual-energy x-ray absorptiometry (DXA) on the participant's spine, converted into T-scores categories using CDC guidelines (T < or = -2.5 [osteoporotic]; -2.5 > T < -1.0 [osteopenic]; > or = -1.0 [normal]). Comparisons were made using multiple regression to determine significant independent risk factors for low BMD.
Results: Significant predictors were noted in the rates of osteoporosis attributable to subject age, race, and level of ambulation. No gender differences were noted for the rate of osteoporosis in this community sample of individuals with intellectual and/or developmental disabilities, nor were any differences noted for varying levels of mental retardation. Diagnostic differences were significant only for those individuals with a diagnosis of metabolic error, who had a significantly lower rate of osteoporosis than the rest of the study population.
Conclusion: This study's findings regarding age, race, and level of ambulation are consistent with those of previous studies using an intellectually and/or developmentally disabled population as well as the general population at large. Our finding that the rate of osteoporosis among disabled males is higher than for males in the general population suggests a possible case-finding deficit for asymptomatic males in the general population. It is also interesting that the only diagnostic category observed to be statistically different from the group in general was metabolic error, a finding that warrants further investigation.