摘要目的:了解中国健康定量CT（QCT）大数据项目2018—2019年入组人群的基线特征。方法:以中国健康定量CT大数据项目2018年1月至2019年12月符合标准的入组人群为研究对象，骨密度和腹内脂肪的测量采用Mindways的定量CT Pro Model 4系统。描述性分析入组人群的年龄、性别、地区分布以及身高、体重、腹围、血压、血常规及血生化等健康指标的基线情况，并采用单因素方差分析分性别对骨密度和腹内脂肪年龄变化趋势进行趋势检验。结果:经对主要指标的纳入排除标准及异常值筛选后，最终86 113例纳入本研究，入组率为92.47%，其中女性35 431例（41.1%），男性50 682例（58.9%），男女比值为1.43。总体年龄为（50.3±12.7）岁，男性为（50.2±12.8）岁，女性为（50.4±12.5）岁，性别差异无统计学意义（ P>0.05）。按地区划分，华东地区入组最多，共43 833例（50.90%），其次为华中地区16 434例（19.08%），东北地区最低2 914例（3.38%）。与主要研究结局相关的健康信息指标入组率基本在70%以上，且两性差异均有统计学意义（均 P<0.05）。女性骨密度为（139.33±46.76）mg/cm 3，男性为（135.90±36.48）mg/cm 3，不同性别骨密度整体表现为随年龄递减趋势（均 P<0.001）；女性腹内脂肪面积为（116.39±56.23）cm 2，男性为（191.67±77.07）cm 2，不同性别整体表现为随年龄递增趋势（均 P<0.001）。 结论:基于QCT测量的基线骨密度和腹内脂肪均存在性别差异且年龄趋势不同，健康信息指标也有性别差异；此外，由于纳入数据的地区差异，也需考虑地区因素。

abstractsObjective:To describe the baseline characteristics of the subjects enrolled in the China Quantitative CT (QCT) big data program in 2018—2019.Methods:Based on baseline data from the Chinese health big data project from January 2018 to December 2019 from the eligible enrolled population, measurements of bone mineral density (BMD) and visceral adipose tissue (VAT) were performed using Mindways′ QCT Pro Model 4 system. The baseline data of age, gender, regional distribution, height, weight, abdominal circumference, blood pressure, blood routine and blood biochemical tests were analyzed. And the single factor analysis of variance (ANOVA) was used to check the age related trend of BMD and VAT in both genders.Results:After screening the inclusion exclusion criteria and outliers of the main indicators, 86 113 people were enrolled in the project. The enrollment rate was 92.47%, including 35 431 (41.1%) women and 50 682 (58.9%) men, and the ratio of men to women was 1.43. The mean age was (50.3±12.7) years in all the subjects, and it was (50.2±12.8) years and (50.4±12.5) years in men and women, respectively, and there was no statistical difference between the two genders ( P>0.05). Total of 43 833 people were enrolled in east China, it was the largest group by region (50.90%), it was followed by central China (16 434 people, 19.08%), and the number of people enrolled in Northeast China was the lowest (2 914 people, 3.38%). The rate of completing of health information indicators related to the main outcome of the study were all above 70%, and there were significant differences between men and women (all P<0.05). The mean BMD was (139.33±46.76) mg/cm 3 in women, (135.90±36.48) mg/cm 3 in men, which showed a decreasing trend with age in both gender (both P<0.001); the mean intra-abdominal fat area was (116.39±56.23) cm 2 in women, (191.67±77.07) cm 2 in men, and there was an increasing trend with age in both men and women (both P<0.001). Conclusions:There are gender differences in BMD and VAT measured by QCT with different age tendency, and there are gender differences in health information index. Regional factors should also be taken into account for regional differences in the inclusion of data.