Osteoporosis in adults with cerebral palsy: feasibility of DXA screening and risk factors for low bone density

Summary: This study aims to describe osteoporosis screening in adults with cerebral palsy (CP) and identify any associated factors. Bone mineral density (BMD) was often lower than expected-for-age in these adults, and present even in young adulthood, particularly at the spine. Low BMD is frequent in adults with CP. Introduction: This study aims to describe the feasibility of dual-energy X-Ray absorptiometry (DXA) screening in adults with cerebral palsy (CP) and identify factors associated with low bone mineral density (BMD), including longitudinal changes. Methods: A retrospective chart review study of these adults seen at an urban academic rehabilitation clinic and who underwent DXA scan(s). BMD and Z-scores for the lumbar spine, hips, and femoral (neck and total) were recorded. The change in BMD and Z-scores from baseline to follow-up DEXA, Gross Motor Functional Classification System (GMFCS), CP pattern (hemiplegic, diplegic, or quadriplegic), body mass index (BMI), and transfer and ambulation status were assessed. Results: Forty-two patients (83 % less than age 50 years) had at least one DXA. Seventeen had at least two studies, 15 without pharmacologic interventions between studies. Thirteen fractures in eight subjects were noted, most often lower limb. Fifty percent of spine studies in individuals under 50 had a Z-score of less than −2, while 25 and 30.8 % of these individuals had such scores at the right and left total hip sites, respectively. Need for transfer assistance was associated with lower BMD and Z-scores at all hip sites, but not the lumbar spine. Progressive abnormalities were seen at follow-up DXAs at some sites, however these were not statistically significant. Conclusions: Lower than expected-for-age BMD was very frequent in adults with CP with mobility limitations, present at both spine and hip sites. Low BMI and need for transfer assistance had a negative impact on BMD. Although not statistically significant, progression of abnormalities was seen at follow-up for DXAs Z-scores at some sites, which suggests longitudinal studies in this population are needed.