# Association between osteoporosis knowledge and bone health in patients with autoimmune diseases: a cross-sectional study

## TL;DR

This study shows that patients with autoimmune diseases who have limited knowledge about osteoporosis tend to have lower bone density and higher osteoporosis risk.

## Contribution

The study is the first to demonstrate a direct association between osteoporosis knowledge and bone health in autoimmune disease patients using latent class analysis.

## Key findings

- Higher osteoporosis knowledge was significantly linked to greater lumbar spine bone mineral density.
- Patients with low osteoporosis knowledge had a 51.7% lower risk reduction of low BMD in the highest knowledge quartile.
- Physical activity and healthy lifestyle behaviors were identified as key factors in reducing osteoporosis risk.

## Abstract

Osteoporosis is a common skeletal disorder among older adults, characterized by reduced bone density and increased susceptibility to fractures, particularly in individuals with autoimmune diseases. Adequate knowledge of osteoporosis and active engagement in bone-protective behaviors may help prevent its onset; however, research examining this hypothesis within autoimmune populations remains limited. This study aimed to evaluate osteoporosis knowledge levels in patients with autoimmune diseases and to investigate the relationship between osteoporosis knowledge scores and bone mineral density (BMD).

This hospital-based cross-sectional study enrolled 562 participants aged 18 years and older who underwent complete dual-energy X-ray absorptiometry (DXA) scans with autoimmune diseases between March 2023 and September 2024. Latent class analysis (LCA) was applied to the four dimensions of the Chinese version of the Osteoporosis Prevention and Awareness Tool (OPAAT-C), namely symptoms, diagnostic methods, preventive measures and risk factors, to classify participants into high, moderate and low knowledge groups, and bone mass was compared across these groups.

This study included 562 adults with autoimmune diseases who completed the OPAAT-C (48.2% male; mean age 45.9 years). The average osteoporosis knowledge score was 12.67 ± 5.63 (57.6% of 22 points). Among 253 patients (45.0%) with low BMD, 78 (30.8%) were in the low knowledge score group based on LCA. Higher osteoporosis knowledge was significantly associated with greater lumbar spine BMD and lower osteoporosis risk. In multivariate linear regression adjusted for all covariates, higher osteoporosis knowledge scores derived from LCA were positively associated with lumbar spine BMD (β = 0.051; 95% CI: 0.013 to 0.088; p = 0.008). In multivariate logistic regression, participants in the highest knowledge quartile (Q4) had a 51.7% lower risk of low BMD compared with those in the lowest quartile (Q1) (OR = 0.481; 95% CI, 0.240 to 0.956; p = 0.038). Mediation analysis showed a significant indirect effect via the action score (β = −0.015; 95% CI: −0.031 to −0.003; p = 0.041), and subgroup analysis revealed a significant interaction between knowledge quartile and sex on lumbar BMD (p = 0.027).

Patients with autoimmune diseases and limited osteoporosis knowledge had significantly lower bone mineral density and an increased risk of osteoporosis. Increasing physical activity and adopting healthy lifestyle behaviors can reduce this risk.