Bone mineral density in adults with osteoarthritis or rheumatoid arthritis: a cross-sectional study of a nationwide population.

Abstract Background It is reported that osteoporosis commonly occurs in rheumatoid arthritis (RA), whereas there is a controversial relationship with osteoarthritis (OA). In this study, we aimed to investigate the relations between OA, RA and bone mineral density (BMD) in adults aged 20–59 years. Methods We merged and analyzed the database from the National Health and Nutrition Examination Survey (NHANES) 2011–2018. Arthritis status and types of arthritis were obtained from questionnaires. Lumbar BMD was measured by dual-energy X-ray absorptiometry. The associations between OA, RA and lumbar BMD were evaluated using logistic regression models. Subgroup analyses stratified by gender and race were performed. The association between disease duration of arthritis and lumbar BMD was also investigated. Results A total of 11094 adults aged 20–59 years were analyzed in this study. Compared with the non-arthritis group, participants with OA had a higher lumbar BMD (β = 0.023; 95% CI: 0.011–0.035), while no significant association was observed in rheumatoid arthritis (β = 0.014; 95% CI: -0.003–0.031). In the subgroup analyses stratified by gender, males with OA had a higher lumbar BMD compared with those without (β = 0.014; 95% CI: -0.003–0.031). However, this association changed in females (β = 0.007; 95% CI: -0.008–0.021). On the other hand, no significant association was observed in RA in both males and females (males: β = 0.023; 95% CI: -0.003–0.048, females: β = 0.008; 95% CI: -0.015–0.031). Moreover, the disease duration of arthritis was not associated with lumbar BMD in both OA (β=-0.0001; 95% CI: -0.0017–0.0015) and RA (β = 0.0006; 95% CI: -0.0012–0.0025). Conclusions The correlation between OA and lumbar BMD differed by sex. Patients with OA were more likely to have higher lumbar BMD in males, but not in females. On the other hand, no significant association was found in RA both in males and females.