Objectives: To investigate the prevalence and the risk factors of Osteoporosis(OP) in patients with rheumatoid arthritis(RA).Methods: Bone mineral density (BMD)of lumbar spine(L2-L4)and left hip (femoral neck,wards and trochanter major) were measured by dual-energy X-ray absorptiometry(DXA) in 106 patiens with RA and in 63 healthy subjects.Some Clinical data such as gender, age,weight,height, course of disease, erythrocyte sedimentation rate(ESR), health assessment questionnaire(HAQ) were recorded and the serum 25(OH)D levels were detected by enzyme-linked immunosorbent assay(ELISA) in 106 patiens with RA.Results: ① A total of 39.6% (42/106)of RA patients, BMD were dianosed as having OP while the percentage of healthy subjects is 22.2%(14/63) and there was significant difference to that observed in the two groups.BMD of all the detected sites in RA was significant lower than that in the controls, except BMD of hip neck (x2=11.525, P=0.003).② The study includes 30 cases of male and 76 cases of female,the proportion of male with OP was 33.3%(10/30) and was no significant difference to that observed in female (42.1%)(32/76)(P=0.056) while BMD of trochanter major in female was significant lower than that in male (0.63±0.16g/cm2 vs 0.72±0.15 g/cm2, t=-2.633,P=0.010).③ There were 30 of 61 female patients (49.2%) with RA in menopause, were determined as OP.This incidence was higher than that of those who were in premenopause [2/15 (13.3%)] (x2=6.347, P=0.012).BMD of all the detected sites in postmenopausal patients was significant lower than that in perimenopausal patients (both P<0.01).④ Those who were dianosed as having OP had lower serum 25(OH)D levels (14.22±5.75ng/ml vs 17.43±6.27ng/ml,t=-2.66,P=0.009)and elder age (60.76±11.83y vs 53.09±13.57y, t=2.991,P=0.003) than those who were not dianosed as having OP.⑤ Course of disease was negatively correlated with the BMD in femoral neck and trochanter major(r=-0.203,-0.350,both P< 0.05), respectively;ESR was negatively correlated with the BMD in the L2,L3 and L4 (r=-0.221,-0.223,-0.200, both P<0.05) , respectively;Negative correlation was also detected between HAQ and BMD of trochanter major (r=-0.209,P=0.032).⑥ There were 34 of 72 patients (47.2%) with RA who were treated with corticostero-ids previously or currently, were determined as OP.This incidence was higher than that of those never so treated [8/34 (23.5%)] (x2=5.419, P=0.020).BMD of all the detected sites in the RA patients who were treated with corticosteroids were lower than that in those without corticosteroid treatment RA was significant lower than that in the controls (both P<0.05).⑦ Analysis of binary logistic regression (enter) was executed to investigate the risk factor in RA-induced osteoporosis.A new target, accounting for whether one patient with RA accompanied with osteoporosis or not, was defined as a dependent variable (0 =not, 1 =yes).Age, sex, course of disease,ESR, serum 25(OH)D levels, HAQ,Whether patients with RA who were treated with corticosteroids or not(0 =not, 1 =yes) and Whether menopause or not (0 =not, 1 =yes)were defined as independent variables.The results showed age (OR=1.056, 95CI:1.018 ~ 1.096, P=0.004), course of disease(OR=1.101, 95CI:1.031 ~ 1.177, P=0.004), corticosteroids (OR=3.060, 95CI:1.195 ~ 7.833, P=0.020)and menopause (OR=6.930,95CI:1.287~ 37.302, P=0.024) were unique risk factors in the occurrence of RA-induced osteoporosis,while 25(OH)D (OR =0.898, 95CI:0.830 ~ 0.972, P=0.008)were protective factor.Conclusions: The development of RA-induced osteoporosis was correlated with age, course of disease ,menopause, corticosteroids and 25(OH)D insufficiency/deficiency.