[The association between blood lipids and calcaneus bone mineral density in children and adolescents aged 6-16 years in Beijing].

Objective: To investigate the association between blood lipid and calcaneus bone mineral density (BMD) in children and adolescents aged 6-16 years in Beijing. Methods: Children and adolescents were selected in 30 schools (8 primary schools, 21 middle schools and one 12-year education school) from Dongcheng, Tongzhou, Fangshan and Miyun districts of Beijing by using a stratified cluster sampling method from November 2017 to January 2018. A total of 14 303 students in grade 1 to 4 of primary school, grade 1 of junior and senior middle school were enrolled after excluding subjects who were not able to participate into this study due to trauma or other uncomfortable physical conditions or with missing key values or with diabetes and kidney diseases. Questionnaire survey, blood lipid and calcaneus BMD were conducted. Multivariate linear regression was applied to quantify the association between calcaneal BMD as a dependent variable and blood lipid level as an independent variable after adjusting for the potential confounding factors. Furthermore, quantile regression was used to analyze the association between blood lipid level and different percentiles (P(25), P(50) and P(75)) of ultrasonic velocity values of bone mineral density, and parallel test was conducted for regression coefficients of different percentiles. Results: A total of 14 303 participants aged (11.4±3.3) years (49.9% boys) were involved in the analysis. The mean age of 14 303 participants was (11.0±3.3) years. 7 142 boys accounted for 49.9%. The mean±SD of calcaneal BMD, total cholesterol (TC), low density lipoprotein-cholesterol (LDL-C), and high density lipoprotein-cholesterol (HDL-C) were (1 540.9±33.8) m/s, (3.90±0.76), (2.18±0.62), and (1.40±0.32) mmol/L, respectively. The P(5)0 (P(25), P(75)) of triglyceride (TG) was 0.69 (0.49-0.94) mmol/L. After the adjustment of age, height, smoking, drinking, vitamin D and calcium supplementation, dairy intake, physical activity, FMI, and MMI, a significantly inverse association (P<0.05) between TG level and calcaneus BMD was observed in both genders, which the regression coefficients (95%CI) in boys and girls were -0.064 (-0.085, -0.044) and -0.073 (-0.094, -0.053), respectively. Conclusion: The level of BMD was associated with TG in boys and girls. Therefore, it is important to prevent children from hypertriglyceridemia for the bone health promotion.目的： 探讨北京市6~16岁儿童青少年血脂水平与跟骨骨密度的关联。 方法： 于2017年11月至2018年1月，采用分层整群抽样的方法在北京市东城、房山、密云以及通州区选择30所学校（包括8所小学，21所中学和1所12年制学校），将小学1~4年级、初中1年级和高中1年级6~16岁学生作为研究对象，排除因外伤等身体不适不能参加体检及关键变量缺失和患有糖尿病、肾脏疾病的学生后，最终共纳入14 303名研究对象。进行问卷调查、血脂和跟骨骨密度测量。以跟骨骨密度为因变量，血脂水平为自变量，调整相关混杂因素后，采用多元线性回归模型进行分析；进一步采用分位数回归分析血脂水平与不同百分位数（P(25)，P(50)和P(75)）超声声速值的跟骨骨密度的关联，并对不同百分位数的回归系数做平行性检验。 结果： 14 303名研究对象年龄为（11.0±3.3）岁，男童占49.9%，跟骨超声声速为（1 540.9±33.8）m/s，总胆固醇（TC）、低密度脂蛋白胆固醇（LDL-C）、高密度脂蛋白胆固醇（HDL-C）和甘油三酯（TG）分别为（3.90±0.76）、（2.18±0.62）、（1.40±0.32）和[P(50)（P(25)，P(75)）：0.69（0.49，0.94）mmol/L]。调整年龄、身高、吸烟、饮酒、维生素D和钙补充情况、乳制品摄入、运动情况、脂肪质量指数和肌肉质量指数后，男童和女童TG与跟骨骨密度的β（95%CI）值分别为-0.064 （-0.085，-0.044）和-0.073（-0.094，-0.053）（P<0.05）。在跟骨超声声速值的P(25)，P(50)和P(75)百分位数上，男、女童TG与跟骨骨密度均有关联（P<0.05），且男童TG与不同百分位数跟骨超声声速值的骨密度关联强度不同（P<0.001）。 结论： 男、女童TG与跟骨骨密度有关联。预防TG水平异常，对促进儿童期骨健康具有重要意义。.