| Objective To explore the incidence and the risk factors of osteopenia in adolescent dancing girls in Lanzhou, Gansu, in order to apply targeting intervention. Methods A cross-sectional randomly stratified method was used to select 462 samples, aged from16 to 20 years old, from the adolescent dancing girls. Bone mineral density was measured using ultrasound bone densitometry. T-score was evaluated comprehensively. Sixty-eight cases were diagnosed of osteopenia and as case group. Three hundred and ninety-four cases were with normal bone mass and as control group. Twelve indexes including age, height, and weight were compared between the two groups. Single factor analysis and multi-factor logistic regression were conducted．Results The detection rate of osteopenia was 14.72%. The analysis of osteoporosis-related factors showed that after excluding other roles into the model, body mass index (BMI) and age of menarche were linearly related to calcaneus stiffness index (SI, P<0.05). BMI was the most impact factor on SI (r=0.121). Age of menarche was negatively associated with SI (r= -0.112). The prevalence of menstrual disorder was 39.18%. The risk of osteopenia increased by 1.88 and 1.92 times, respectively, in people with menstrual disorder and smoking comparing to those with normal menstruation and nonsmoking. The risk of osteopenia was 1.84, 2.20, and 2.65 times more in people with less intake of milk products and soy products and dieting than in those with normal intake (OR=1.88, 1.92, 1.84, 2.20, and 2.62, respectively, the 95% confidence interval not containing 1, P<0.05). Conclusion Late age of menarche, low body mass index, menstrual disorder, smoking, less intake of milk products and soy products, and dieting are main risk factors of osteopenia. |