Factors influencing abnormal bone mineral density in Chinese women aged 40 years and older: A meta-analysis.

Abnormal bone mineral density (BMD), including osteopenia/low bone mass and osteoporosis, imposes a substantial clinical and socioeconomic burden on Chinese women. However, prevalence estimates vary markedly because primary studies differ in age composition, study setting, and the BMD outcome category reported. To systematically review and meta-analyze the prevalence of distinct BMD outcomes and the influencing factors associated with abnormal BMD among Chinese women aged 40 years and older. We searched nine international and Chinese databases from inception to July 10, 2025, for cross-sectional or case-control studies involving Chinese women aged 40 years or older. Prevalence was synthesized separately for abnormal BMD, osteopenia/low bone mass, and osteoporosis. Twenty-eight studies comprising 36,984 participants were included. Outcome-specific meta-analyses showed a pooled prevalence of 61 percent for abnormal BMD (95 percent CI: 50 percent-72 percent; n = 17,294), 41 percent for osteopenia/low bone mass (95 percent CI: 37 percent-46 percent; n = 19,032), and 29 percent for osteoporosis (95 percent CI: 23 percent-35 percent; n = 35,082). Heterogeneity remained substantial (I2 = 99.5 percent, 97.1 percent, and 99.1 percent). Postmenopausal status, menopause duration > 5 years, older age, BMI < 18 kg/m2, lack of exercise, low vitamin D intake, and fracture history were associated with higher odds of abnormal BMD, whereas regular exercise, dairy products, bean products, and calcium supplementation were protective. Abnormal BMD represents a substantial bone-health burden among Chinese women aged 40 years and older. Outcome-specific meta-analyses showed pooled prevalence estimates of 61 percent for abnormal BMD, 41 percent for osteopenia/low bone mass, and 29 percent for osteoporosis. Both non-modifiable susceptibility factors and potentially modifiable lifestyle and nutritional factors were associated with abnormal BMD. These findings support risk-based BMD assessment and targeted strategies addressing modifiable factors, including physical activity and adequate calcium and vitamin D intake, to promote bone health in middle-aged and older Chinese women.