Abstract: Objective  To explore the relationship between body composition and lumbar bone mineral density (BMD) in perimenopausal and postmenopausal women, and to further analyze the influencing factors of bone loss in this population. Methods  A total of 300 perimenopausal and postmenopausal women who were admitted to the Department of Endocrinology, Beijing Obstetrics and Gynecology Hospital, Capital Medical University from October 2021 to March 2024 were recruited as subjects. The age, menopausal status, and activity type of all subjects were collected with the menopausal symptom comprehensive assessment scale. The bone density of the lumbar spine was measured with quantitative computed tomography (QCT) and the subjects were divided into normal bone mass group and low bone mass group, according to the measurement results. The body composition of all subjects, such as body weight, fat, lower limb muscle, and knee joint activity was measured with muscle function analyzer. One-Way analysis of variance was used to compare the differences in body composition between the normal bone mass group and the osteopenia group. Multivariate Logistic regression analysis was used to explore the risk factors of osteopenia.Results  Among the 300 subjects, there were 148 (49%) perimenopausal women, with an average age of (51.40±5.03) years and 152 postmenopausal women (51 %), with an average age of (53.59±6.04) years. The BMD of postmenopausal women was significantly lower than that of perimenopausal women (P<0.05 ). There were 118 cases (39%) in the low bone mass group and 182 cases (61%) in the normal bone mass group. The age, percentage of fat, proportion of postmenopausal women and proportion of women without exercise in low bone mass group were significantly higher than those in normal bone mass group (P<0.05 ). The lower limb muscle distribution coefficient, lower limb muscle strength, and the proportion of exercise were significantly lower than those in the normal bone mass group (P<0.05 ),respectively. Spearman correlation analysis showed that BMD in perimenopausal and postmenopausal women was significantly negatively correlated with age, fat percentage, and proportion of postmenopausal women (r=-0.492, -0.125, -0.287, P < 0.05 ), while it was significantly positively correlated with lower limb muscle distribution coefficient, lower limb muscle strength, and proportion of exercise (r=0.143,0.180,0.193, P < 0.05 ). Binary Logistic regression analysis showed that older age, higher percentage of fat, less muscle distribution of lower limbs, and less exercise were risk factors for bone loss (P<0.05 ).Conclusions  Compared with perimenopausal women, the BMD of lumbar vertebrae in postmenopausal women was significantly lower. The BMD of lumbar vertebrae in perimenopausal and postmenopausal women was closely related to body composition and activity type. Older age, higher percentage of fat, less muscle distribution of lower limbs and less exercise were risk factors for bone loss (P<0.05 ). It is suggested that clinicians should pay attention to the changes of lumbar BMD and body composition of women in this period, so as to improve their quality of life and prevent the occurrence of osteoporosis through timely and reasonable intervention measures.

Key words: perimenopausal and postmenopausal, lumbar bone mineral density, human body composition, bone loss