To investigate the prevalence and influencing factors of abnormal bone mass in postmenopausal women of Dong and Miao ethnic groups in Guizhou Province, and to establish a nomogram prediction model and verify it, so as to provide theoretical basis for the prevention of abnormal bone mass in ethnic minority postmenopausal women in Guizhou Province.

This study was a cross-sectional study. In total 3 208 postmenopausal women of Dong and Miao ethnic groups were selected from the cohort study database of natural population of ethnic minorities in southwest China, and ultrasonic bone densitometer was used to measure calcaneal bone mineral density (BMD). The concentrations of cadmium, cobalt, copper, chromium, iron, mercury, manganese, molybdenum, nickel, lead, strontium, vanadium, and zinc in urine were determined by inductively coupled plasma mass spectrometer, and the relationship between urine metal, demographic characteristics, reproductive characteristics, ethnic diet, and BMD was analyzed by binary logistic regression, and the risk prediction model of bone mass abnormality was established.

A total of 3 208 people were included in the study, and a total of 1 520 people with abnormal bone mass were detected. The detection rate of abnormal bone mass was 47.38%. Based on age (OR=1.098, 95%CI: 1.083-1.113),history of bone fracture (OR=0.560, 95%CI: 0.395-0.794), age of menopause (OR=0.965, 95%CI: 0.949-0.982), number of live births (OR=0.900, 95%CI: 0.818-0.990), use of contraceptive (OR=0.708, 95%CI: 0.555-0.901), total physical activity (OR=0.989, 95%CI: 0.984-0.994), urinary cadmium (OR:1.060, 95%CI:1.009-1.113), and urinary chromium (OR=1.004, 95%CI:1.001-1.008) were independent influencing factors of abnormal bone mass. To establish a predictive model Logit (P) for predicting the risk of abnormal bone mass in postmenopausal women: Logit (P) =-2.170+0.093 * (age)-0.580 * (history of bone fracture)-0.035 * (menopausal age)-0.105 * (number of live births)-0.346* (whether or not you have taken contraceptive)-0.011 *(total physical activity) + 0.058 * (urinary cadmium) + 0.004 * (urinary chromium). The area under the receiver operating characteristic curve of the model was 0.722. The nomogram was drawn and verified internally. The results showed that the calibration curve predicted by the model for abnormal bone mass was basically consistent with the actual curve, and the fitting effect was good.

Cadmium and chromium are independent risk factors of abnormal bone mass, indicating that metal exposure can affect the occurrence and development of abnormal bone mass. The prediction model and score diagram of bone mass abnormality have good predictive ability, which provides a reference for screening abnormal bone mass of minority postmenopausal women in Guizhou Province.