Context: Cerebral palsy (CP) increases fracture risk through diminished ambulation, nutritional deficiencies, and anticonvulsant medication use. Studies examining bone mineral density (BMD) in adults with CP are limited.
Objective: To examine the relationship between body composition, BMD, and fractures in adults with CP. The effect of functional, nutritional, and endocrine factors on BMD and body composition is also explored.
Design: Retrospective cross-sectional study.
Setting and participants: Forty-five adults with CP (mean age, 28.3 ± 11.0 years) who had dual-energy x-ray absorptiometry imaging at a single tertiary hospital between 2005 and 2015.
Results: Seventeen (38%) had a past history of fragility fracture; 43% had a Z-score of ≤ -2.0 at the lumbar spine (LS) and 41% at the femoral neck (FN). In nonambulatory patients, every one unit decrease in FN Z-score increased the risk of fracture 3.2-fold (95% confidence interval, 1.07-9.70; P = .044). Stepwise linear regression revealed that the Gross Motor Function Classification System was the best predictor of LS Z-score (R(2) = 0.550; β = -0.582; P = .002) and FN Z-score (R(2) = 0.428; β = -0.494; P = .004); 35.7% of the variance in BMD was accounted for by lean tissue mass. Hypogonadism, present in 20% of patients, was associated with reduced lean tissue mass and reduced LS BMD. Lean tissue mass positively correlated with BMD in eugonadal patients, but not in hypogonadal patients.
Conclusions: Low BMD and fractures are common in adults with CP. This is the first study to document hypogonadism in adults with CP with detrimental changes in body composition and BMD.