It is reported that osteoporosis commonly occurs among patients with rheumatoid arthritis (RA), whereas the association between osteoporosis and osteoarthritis (OA) remains controversial. Our aim in this study was to investigate the association between BMD, as a marker of osteoporosis, and OA and RA among adults 20-59 years of age, using a population-based sample from the National Health and Nutrition Examination Survey (NHANES).
Our analysis was based on the NHANES data collected between 2011 and 2018. Data regarding arthritis status and the type of arthritis (OA or RA) were obtained from questionnaires. Lumbar BMD was measured by dual-energy X-ray absorptiometry. The association between OA, RA, and lumbar BMD was evaluated using logistic regression models. Subgroup analyses, stratified by gender and race, were performed. The association between duration of arthritis and lumbar BMD was also investigated.
A total of 11,094 adults were included in our study. Compared to the non-arthritis group, participants with OA had a higher lumbar BMD (β = 0.023, 95% CI 0.011-0.035), with no significant association between lumbar BMD and RA (β = 0.014, 95% CI - 0.003 to 0.031). On subgroup analyses stratified by gender, males with OA had a higher lumbar BMD compared to those without OA (β = 0.047, 95% CI 0.028-0.066). In females, OA was not associated with lumbar BMD (β = 0.007, 95% CI - 0.008 to 0.021). There was no association between lumbar BMD and RA in both males (β = 0.023, 95% CI - 0.003 to 0.048) and females (β = 0.008, 95% CI - 0.015 to 0.031). Duration of arthritis was not associated with lumbar BMD for both OA (β = - 0.0001, 95% CI - 0.0017 to 0.0015) and RA (β = 0.0006, 95% CI - 0.0012 to 0.0025).
Lumbar BMD was associated with OA but not with RA. While a higher lumbar BMD was associated with OA in males, but not in females. Our findings may improve our understanding between OA, RA, and bone health.