| Objective To investigate the relationship between the age at first delivery and the risk of osteoporosis in Chinese menopausal women. Methods This study was performed using data of bone mineral density testing in our hospital from 2015 to 2018 and included 253 Chinese postmenopausal women. The diagnosis of osteoporosis was made using the World Health Organization T-score criteria (T-score <–2.5 at femoral neck or lumbar spine). Participants were categorized into 3 groups according to age at first delivery: <23, 24-29, and >30 years. Results Older age, lower body mass index, lower calcium intake, later menarche, and earlier menopause increased the risk of osteoporosis, whereas hormone therapy and oral contraceptive use were associated with a decreased risk of osteoporosis. Postmenopausal women whose first delivery occurred at age 24-29 years were shown to have a significantly increased risk of osteoporosis (odds ratio, 2.124; 95% confidence interval, 1.096-4.113; P = 0.026) compared with those who first gave birth after the age of 30 years. Conclusions These findings suggest that postmenopausal women whose first delivery occurred at age 24-29 years, a period during which bone mass slowly accumulates to the peak, are at an increased risk of osteoporosis. |