Longitudinal Changes in Bone Density in Adolescents and Young Adults with Cerebral Palsy: A Case for Early Intervention.

Context Cerebral palsy (CP) is a motor disorder affecting movement, muscle tone and posture due to damage to the foetal or infant brain. The subsequent lack of ambulation, nutritional deficiencies, anticonvulsant use and hormonal deficiencies have been implicated in the low bone mass associated with this condition. Objective To assess changes in areal bone mineral density (aBMD) during adolescence and young adulthood in individuals with CP. The effect of ambulation, nutrition, hypogonadism on longitudinal changes in aBMD is also examined. Design Retrospective longitudinal study. Setting and participants Forty-five subjects with CP who had longitudinal dual-energy X-ray absorptiometry (DXA) scans at a single tertiary hospital between 2006 and 2018. Results Mean age at first DXA was 19.4 years (range: 10-36 years), 57.8% were male and 80% were nonambulatory. The mean Z-scores at baseline were <-2.0 at all sites - lumbar spine (LS), femoral neck (FN), total hip (TH) and total body (TB). The median change in aBMD was +1.2%-1.9% per year in all subjects but in those <20 years of age, the median change was 4%-8% per year. Z-scores across all sites remained stable over time. Reduced functional state as measured by the gross motor functional classification scale (GMFCS) had a small negative effect on aBMD over time. Conclusion In adolescents with CP, low bone mass was evident from the baseline DXA. However, significant bone accrual occurred during the second decade, followed by bone maintenance in young adulthood. Future studies should focus on optimizing bone health from early childhood.