Modulation of Bone Mineral Density and Its Response to Menopausal Hormone Therapy according to the Apolipoprotein E Genotype in Postmenopausal Korean Women.

ABSTRACT

OBJECTIVES: Genetic factors are a major cause of osteoporosis. The present study evaluated the association of the apolipoprotein E (ApoE) genotype with bone mineral density (BMD) and its response to menopausal hormone therapy (MHT) in postmenopausal Korean women. METHODS: This retrospective cohort study included 172 postmenopausal women with no endocrine diseases, medications, or lifestyles that would affect bone metabolism and who were continuously treated with MHT for at least 2 years. BMDs were measured at baseline and periodically. RESULTS: Linear regression analysis demonstrated similar baseline BMDs at the lumbar spine, but significantly lower at the femur neck and total hip in the ApoE ε4 carrier than in the noncarrier group, after controlling for age, body mass index, and history of MHT usage. Overall, the Wilcoxon signed rank test demonstrated that MHT increased the BMD percentage change at all three regions, and the Generalized Estimating Equation (GEE) demonstrated significant time trends at the lumbar spine and femur neck. ApoE ε4 noncarriers exhibited a significant time trend in BMD changes at the femur neck, whereas ε4 carriers exhibited a time trend at the lumbar spine. However, BMD changes at each time point were comparable at all regions between the groups. Notably, GEE adjusted for baseline characteristics and BMD revealed a significant interaction effect of time and ApoE ε4 allele in BMD changes at the femur neck. CONCLUSIONS: Postmenopausal Korean women carrying the ApoE ε4 allele demonstrated a lower hip BMD compared with ε4 noncarriers. Furthermore, the ε4 allele may modulate hip BMD responses to MHT.