Analysis of osteoporosis related factors in premenopausal patients with early rheumatoid arthritis

Abstract

Objective To identify the clinical features and risk factors of early rheumatoid arthritis (RA)-associated osteoporosis in premenopausal women. Methods A total of 76 premenopausal women with early RA were randomly selected in the Department of Kidney and Rheumatology in the hospital. A total of 84 health cases were randomly selected in our hospital as controls. Bone mineral density (BMD) was determined using dual energy X-ray absorptiometry (DEX). Bone metabolism (CTX, PINP) and inflammatory cytokines (IL-17, IL-6, TNF-α) were examined with quantitative enzyme-linked immune-sorbent assay (ELISA).Quantitative data were expressed as ±s deviation and the data were compared between groups using non-parametric test (Z value). Multi-group comparison was performed with variance analysis. Qualitative data were compared with Fisher's test. Logistic regression was used to investigate the risk factors. Results ① Compared with the control group, BMD in the premenopausal women with early RA group [neck: (0.802±0.193) g/cm2, GT zone: (0.923±0.033) g/cm2, L1: (0.862±0.011) g/cm2] was significantly decreased [(0.981±0.032) g/cm2, (0.771±0.023) g/cm2, (0.912±0.012) g/cm2, F=14.401, 19.860, 6.560, respectively, both P<0.05). The prevalence of osteoporosis in this group was 7%(5/76), which was higher than controls 1%(1/84). ② According to values of Bone meta-bolism [(CTX: (0.37±0.21) ng/ml] and inflammatory cytokines, TNF-α: (9.8±4.1) pg/ml, IL-6: (33.6±5.7) pg/ml and IL-17: (129±24) pg/ml were markedly increased in premenopausal women in early RA group [(0.24±0.09) ng/ml, (6.7±1.9) pg/ml, (1.5±0.4) pg/ml, (45±7) pg/ml, Z=2.722, 5.932, 7.501, 4.370, respectively, both P<0.05]. ③ The premenopausal women with early RA group with osteoporosis were signifi-cantly difference with controls in BMI [(9±3) kg/m2vs (16±3) kg/m2], bone density of neck [(0.85±0.20) ng/ml vs (0.88±0.14) g/cm2], L2 [(0.75±0.23) g/cm2vs (0.88±0.14) g/cm2], L3 [(0.87±0.07) g/cm2vs (0.93±0.14) g/cm2], L4 [(0.92±0.12) g/cm2vs (0.94±0.16) g/cm2], serum ESR [47.8(22.0, 76.0) mm/1 h vs 18.8(8.7, 35.2) mm/1 h] and DAS28-CRP (5.3±1.2 vs 3.8±1.2) F=0.68, 14.632, 26.114, 20.931, 36.582, Z=3.21, 6.58, respectively, both P<0.05. ④ Logistic regression showed that IL-6 (Wald χ2=5.78, P=0.021) , PINP (Wald χ2=5.12, P=0.031), CTX (Wald χ2=9.17, P=0.003), ESR (Wald χ2=9.24, P=0.011), DAS28-CRP (Wald χ2=17.28, P=0.001) were significantly positively correlated with osteoporosis. Moreover, ordered unconditional Logistic regression analysis of the variables (IL-6, PINP, CTX, ESR, DSA28) described above showed that DAS 28-CRP score [OR=1.58, 95% CI: (1.10, 2.20)] was the most important risk factor for osteoporosis in premenopausal women with early RA. Conclusion The incidence of osteoporosis is high in premenopausal women with early RA than healthy cases. DAS 28-CRP score is the important risk factor for premenopausal women with early RA-associated osteoporosis. Measures relieve symptoms of RA can help to prevent and treatment osteoporosis. Key words: Arthritis, rheumatiod; Premenopausal women; Osteoporosis; Bone Mineral Density; Early