Objective: To investigate the association of urinary cadmium level with body mass index (BMI) and body circumferences among the older adults over 65 years old in 9 longevity areas of China. Methods: Subjects were older adults over 65 years old from the Healthy Aging and Biomarkers Cohort Study (HABCS) between 2017 and 2018 conducted in 9 longevity areas in China. A total of 1 968 older adults were included in this study. Information including socio-demographic characteristics, lifestyles, diet intake, and health status was collected by using questionnaires and physical examinations. Urine samples were collected to detect urinary cadmium and creatinine levels. Body circumferences included waist circumference, hip circumference and calf circumference. Subjects were divided into three groups (low:<0.77 μg/g·creatinine, middle:0.77-1.69 μg/g·creatinine, high:≥1.69 μg/g·creatinine) by tertiles of creatinine-adjusted urinary cadmium concentration. Multiple linear regression models were used to analyze the association of creatinine-adjusted urinary cadmium level with BMI and body circumferences. The dose-response relationship of creatinine-adjusted urinary cadmium concentration with BMI and body circumferences was analyzed by using restrictive cubic splines fitting multiple linear regression model. Results: The mean age of subjects was (83.34±11.14) years old. The median (Q1, Q3) concentration of creatinine-adjusted urinary cadmium was 1.13 (0.63, 2.09) μg/g·creatinine, and the BMI was (22.70±3.82) kg/m2. The mean values of waist circumference, hip circumference, and calf circumference were (85.42±10.68) cm, (92.67±8.90) cm, and (31.08±4.76) cm, respectively. After controlling confounding factors, the results of the multiple linear regression model showed that for each increment of 1 μg/g·creatinine in creatinine-adjusted urinary cadmium, the change of BMI, waist circumference, hip circumference, and calf circumference in the high-level group was -0.28 (-0.37, -0.19) kg/m2, -0.74 (-0.96, -0.52) cm, -0.78 (-0.96, -0.61) cm, and -0.20 (-0.30, -0.11) cm, respectively. The restrictive cubic splines curve showed a negative nonlinear association of creatinine-adjusted urinary cadmium with BMI (Pnonlinear<0.001) and negative linear associations of creatinine-adjusted urinary cadmium with waist circumference (Plinear<0.001), hip circumference (Plinear<0.001), and calf circumference (Plinear<0.001). Conclusion: Urinary cadmium level is significantly associated with decreased BMI, waist circumference, hip circumference and calf circumference among older adults over 65 years old in 9 longevity areas of China.
目的： 研究我国9个长寿地区65岁及以上老年人尿镉与体重指数（BMI）及身体围度的关联。 方法： 研究对象来自2017—2018年在我国9个长寿地区开展的“中国老年健康生物标志物队列研究”，共计1 968名65岁及以上老年人被纳入本研究。通过问卷调查和体格检查，收集调查对象的社会人口学特征、生活方式、膳食摄入和健康状态等信息，采集调查对象晨尿以检测尿镉和尿肌酐水平；身体围度包括腰围、臀围和小腿围。根据尿肌酐校正后尿镉水平三分位数将调查对象分为低水平组（<0.77 μg/g·肌酐）、中水平组（0.77~1.69 μg/g·肌酐）和高水平组（≥1.69 μg/g·肌酐），采用多重线性回归模型分析尿肌酐校正后尿镉不同水平与BMI及身体围度的关联，采用限制性立方样条拟合多重线性回归模型分析尿肌酐校正后尿镉水平与BMI及身体围度的剂量-反应关系。 结果： 1 968名研究对象年龄为（83.34±11.14）岁，尿肌酐校正后尿镉水平的M（Q1，Q3）为1.13（0.63，2.09）μg/g·肌酐，BMI为（22.70±3.82）kg/m2，腰围为（85.42±10.68）cm，臀围为（92.67±8.90）cm，小腿围为（31.08±4.76）cm。多重线性回归模型分析结果显示，调整相关混杂因素后，尿肌酐校正后尿镉每增加1 μg/g·肌酐，BMI、腰围、臀围和小腿围的变化水平β（95%CI）值分别为-0.28（-0.37，-0.19）kg/m2、-0.74（-0.96，-0.52）cm、-0.78（-0.96，-0.61）cm和-0.20（-0.30，-0.11）cm；限制性立方样条模型结果显示，尿肌酐校正后尿镉水平与BMI呈负向非线性关联（P非线性<0.001），与腰围、臀围和小腿围呈负向线性关联（均P线性<0.001）。 结论： 中国9个长寿地区65岁及以上老年人尿肌酐校正后尿镉水平与BMI、腰围、臀围和小腿围呈负向关联。.