Objective: To evaluate the relationship between the presence of apolipoprotein E (Apo E) 4 allele and bone mineral density (BMD) and severity of joint destruction in postmenopausal women with rheumatoid arthritis (RA). Methods: Apo E genotypes were analyzed in 113 postmenopausal women who were first diagnosed with RA and had not receiving antiresorptive therapy for osteoporosis at the time of enrollment. BMD was measured using dual-energy X-ray absorptiometry (DEXA), and joint destruction was evaluated on plain radiographs according to 'Larsen score'. The differences in BMD and severity of joint destruction in groups with and without an Apo E4 allele were analyzed in 94 patients with clinical information available. Results: BMD (g/cm²) of the lumbar spine in the Apo E4 (⁣) group was 0.94⁑0.16 (n=67), whereas that in the Apo E4 (⁢) group was 0.87⁑0.14 (n=27; p=0.049). BMD of the femoral neck and great trochanter in the Apo E4 (⁣) group was 0.74⁑0.12 and 0.63⁑0.11, while that in the Apo E4 (⁢) group was 0.68⁑0.11 (p=0.039) and 0.57⁑0.11 (p=0.008). However, there were no significant differences in Larsen scores and erosive disease (%) between the Apo E4 (⁢) and Apo E4 (⁣) groups. Conclusion: The Apo E4 allele is associated with a reduced bone mass in postmenopausal RA patients. Therefore, Apo E4 allele is considered to be an independent risk factor for generalized osteoporosis in postmenopausal RA patients.

Keywords: Rheumatoid arthritis, Apolipoprotein E, Osteoporosis