Abstract
Background
High bone mass (HBM, BMD Z-score ≥ + 3.2) and cam morphology (bulging of lateral femoral head) are associated with greater odds of prevalent radiographic hip osteoarthritis (rHOA). As cam morphology is itself a manifestation of increased bone deposition around the femoral head, it is conceivable that cam morphology may mediate the relationship between HBM and rHOA. We therefore aimed to determine if individuals with HBM have increased odds of prevalent cam morphology. In addition, we investigated whether the relationship between cam and prevalent and incident osteoarthritis was preserved in a HBM population.
Methods
In the HBM study, a UK based cohort of adults with unexplained HBM and their relatives and spouses (controls), we determined the presence of cam morphology using semi-automatic methods of alpha angle derivation from pelvic radiographs. Associations between HBM status and presence of cam morphology, and between cam morphology and presence of rHOA (or its subphenotypes: osteophytes, joint space narrowing, cysts, and subchondral sclerosis) were determined using multivariable logistic regression, adjusting for age, sex, height, weight, and adolescent physical activity levels. The association between cam at baseline and incidence of rHOA after an average of 8 years was determined. Generalised estimating equations accounted for individual-level clustering.
Results
The study included 352 individuals, of whom 235 (66.7%) were female and 234 (66.5%) had HBM. Included individuals contributed 694 hips, of which 143 had a cam deformity (20.6%). There was no evidence of an association between HBM and cam morphology (OR = 0.97 [95% CI: 0.63–1.51], p = 0.90) but a strong relationship was observed between cam morphology and rHOA (OR = 3.96 [2.63–5.98], p = 5.46 × 10–11) and rHOA subphenotypes joint space narrowing (OR = 3.70 [2.48–5.54], p = 1.76 × 10–10), subchondral sclerosis (OR = 3.28 [1.60–6.60], p = 9.57 × 10–4) and osteophytes (OR = 3.01 [1.87–4.87], p = 6.37 × 10–6). Cam morphology was not associated with incident osteoarthritis (OR = 0.76 [0.16–3.49], p = 0.72).
Conclusions
The relationship between cam morphology and rHOA seen in other studies is preserved in a HBM population. This study suggests that the risk of OA conferred by high BMD and by cam morphology are mediated via distinct pathways.
High bone mass (HBM, BMD Z-score ≥ + 3.2) and cam morphology (bulging of lateral femoral head) are associated with greater odds of prevalent radiographic hip osteoarthritis (rHOA). As cam morphology is itself a manifestation of increased bone deposition around the femoral head, it is conceivable that cam morphology may mediate the relationship between HBM and rHOA. We therefore aimed to determine if individuals with HBM have increased odds of prevalent cam morphology. In addition, we investigated whether the relationship between cam and prevalent and incident osteoarthritis was preserved in a HBM population.
Methods
In the HBM study, a UK based cohort of adults with unexplained HBM and their relatives and spouses (controls), we determined the presence of cam morphology using semi-automatic methods of alpha angle derivation from pelvic radiographs. Associations between HBM status and presence of cam morphology, and between cam morphology and presence of rHOA (or its subphenotypes: osteophytes, joint space narrowing, cysts, and subchondral sclerosis) were determined using multivariable logistic regression, adjusting for age, sex, height, weight, and adolescent physical activity levels. The association between cam at baseline and incidence of rHOA after an average of 8 years was determined. Generalised estimating equations accounted for individual-level clustering.
Results
The study included 352 individuals, of whom 235 (66.7%) were female and 234 (66.5%) had HBM. Included individuals contributed 694 hips, of which 143 had a cam deformity (20.6%). There was no evidence of an association between HBM and cam morphology (OR = 0.97 [95% CI: 0.63–1.51], p = 0.90) but a strong relationship was observed between cam morphology and rHOA (OR = 3.96 [2.63–5.98], p = 5.46 × 10–11) and rHOA subphenotypes joint space narrowing (OR = 3.70 [2.48–5.54], p = 1.76 × 10–10), subchondral sclerosis (OR = 3.28 [1.60–6.60], p = 9.57 × 10–4) and osteophytes (OR = 3.01 [1.87–4.87], p = 6.37 × 10–6). Cam morphology was not associated with incident osteoarthritis (OR = 0.76 [0.16–3.49], p = 0.72).
Conclusions
The relationship between cam morphology and rHOA seen in other studies is preserved in a HBM population. This study suggests that the risk of OA conferred by high BMD and by cam morphology are mediated via distinct pathways.
| Original language | English |
|---|---|
| Article number | 757 |
| Number of pages | 11 |
| Journal | BMC Musculoskeletal Disorders |
| Volume | 23 |
| Issue number | 1 |
| DOIs | |
| Publication status | Published - 6 Aug 2022 |
Bibliographical note
Funding Information:The HBM study was supported by The Wellcome Trust (ref. 080280/Z/06/Z), the National Institute for Health Research Clinical Research Network (portfolio no. 5163) and Versus Arthritis (ref. 20000). AH was funded by the Wellcome Trust (ref. 20378/Z/16/Z). MRW was supported by the NIHR Biomedical Research Centre at University Hospitals Bristol and Weston NHS Foundation Trust and the University of Bristol. The views expressed are those of the author(s) and not necessarily those of the NIHR or the Department of Health and Social Care. BGF is supported by a Medical Research Council (MRC) clinical research training fellowship (ref. MR/S021280/1). CL is funded by a Sir Henry Dale Fellowship jointly funded by the Wellcome Trust and the Royal Society (223267/Z/21/Z). This research was funded in whole, or in part, by the Wellcome Trust [Grant numbers 080280/Z/06/Z, 20378/Z/16/Z, 223267/Z/21/Z]. For the purpose of open access, the authors have applied a CC BY public copyright licence to any Author Accepted Manuscript version arising from this submission.
Funding Information:
We would like to thank all High Bone Mass study participants and the staff at the University of Bristol and collaborating centres: The Wellcome Trust Clinical Research Facility in Birmingham, Royal National Hospital for Rheumatic Diseases in Bath, Cambridge NIHR Biomedical Research Centre and Addenbrooke's Wellcome Trust Clinical Research Facility, Bone Research Unit in Cardiff, Musculoskeletal Research Unit in Bristol, NIHR Bone Biomedical Research Unit in Sheffield and the Brocklehurst Centre for Metabolic Bone Disease in Hull. No minor participants (< 16 yrs) were involved in this study.
Publisher Copyright:
© 2022, The Author(s).