Context: Cerebral palsy (CP) is the most common motor disorder in children, with impaired mobility, increased falls and fracture risk. With increasing life expectancy, a greater understanding of bone fragility in CP is paramount as fractures further limit mobility.
Objective: The influence of clinical factors and body composition on bone microarchitecture, as defined by trabecular bone score (TBS), bone mineral density (BMD) and fractures in adults with CP was determined.
Design: Retrospective cross-sectional study.
Setting and Participants: 43 adults (25 male) with CP of median age 25 years (interquartile range 21.4 - 33.9) who had dual-energy x-ray absorptiometry (DXA) imaging of the lumbar spine from a single tertiary hospital between 2005-March 2018. TBS was calculated retrospectively using TBS iNsight Software (version 3.0.2.0, Medimaps).
Results: 29/43 (67.4%) of adults were non-ambulatory and 15/43 (34.9%) had a prevalent fragility fracture. Low BMD (Z-score ≤-2) at the lumbar spine (LS) and femoral neck (FN) was seen in 51.2% and 40% respectively. 8/43 (18.6%) had partially degraded and 16/43 (37.2%) had degraded TBS. TBS correlated with BMD at the LS, FN and total body. TBS was significantly associated with arm and leg lean mass, with adjustment for age, gender and height (adjusted R2 =0.18, p=0.042 for arm lean mass; adjusted R2 = 0.19, p=0.036 for leg lean mass). There was no association between fat mass and TBS. There was no difference in TBS when patients were grouped by fracture status, anticonvulsant use, gonadal status or PEG feeding. TBS was lower in non-ambulatory patients compared with ambulatory patients (1.28 vs 1.37, p=0.019).
Conclusions: Abnormal bone microarchitecture, measured by TBS, was seen in more than 50% of young adults with CP. TBS correlated with both areal BMD and appendicular lean mass confirming the importance of maintaining muscle function for bone health in young adults with CP.