摘要目的：观察和分析环境镉污染区人群机体镉负荷及肾损伤的动态变化。方法于2011年4至7月在我国广东省粤北地区选择某镉污染区作为调查地区。依据土壤和大米中镉污染水平将调查地区分为低、高暴露组。其中，大米镉均值在0.15~0.40 mg/kg且土壤镉均值0.5~1.0 mg/kg为低镉暴露组；大米镉均值>0.40 mg/kg且土壤镉均值>1.0 mg/kg为高镉暴露组。以分层随机抽样与整群抽样结合的方法抽取在当地居住15年以上、年龄>40周岁、无职业镉暴露的人群作为调查对象，共计414名，其中低暴露组168名，高暴露组246名。又于2014年3至6月，对上述调查对象进行追踪随访，共随访到305名，其中低暴露组116名、高暴露组189名。通过个人健康问卷了解调查对象的健康状况，采用四分法入户采集调查对象自产的大米、蔬菜，测定其镉含量，其中，2011年采集大米、蔬菜分别为190份、161份，2014年分别为190份、153份；收集调查对象晨尿样本，测定尿镉及肾损伤标志物N?乙酰?β?氨基葡萄糖甘酶(NAG)、β2?微球蛋白(β2?MG)和尿肌酐含量。采用χ2检验比较2011与2014年大米和蔬菜中的镉含量超标率差异及调查对象尿镉、NAG、β2?MG异常率的差异，并以OR (95%CI)值表示相对危险度。结果随访时大米镉含量P50(P25~P75)为0.42(0.20~1.14) mg/kg ,2011年为0.43(0.17~1.10) mg/kg（Z=-0.77, P=0.440）。随访时蔬菜镉含量P50(P25~P75)为0.25(0.12~0.59) mg/kg，高于2011年[0.13(0.07~0.34) mg/kg](Z=-4.69，P<0.001)；超标率为60.8%(93/153)，亦高于2011年[38.5%（62/161）](χ2=15.58，P<0.001)。随访时高暴露组调查对象尿镉含量P50(P25~P75)为8.64(4.56~17.60)μg/g肌酐，高于2011年[7.90(3.96~14.91)μg/g肌酐](Z=-2.80，P=0.005)。随访时调查对象尿β2?MG含量P50(P25~P75)为0.15(0.07~0.45)μg/g肌酐，2011年为0.15(0.07~0.29)μg/g肌酐(Z=-2.263，P=0.024)；尿β2?MG异常率为15.1%(46/305)，高于2011年[7.5%(23/305)](χ2=15.61，P<0.001)，是2011年的2.00倍(OR=2.00，95%CI：1.23~3.24)。随访时尿NAG含量P50(P25~P75)为13.55(9.1~19.84) U/g肌酐，高于2011年[7.12(5.05~10.65) U/g肌酐]（Z=-12.52，P<0.001）；尿NAG异常率为33.8%（103/305），高于2011年[8.2%(25/305)](χ2=64.72，P<0.001)，是2011年的4.12倍(OR=4.12，95%CI：2.87~5.92）。结论环境镉对调查地区大米、蔬菜等农作物的污染持续存在，调查对象机体镉负荷水平持续较高，肾损伤呈加重趋势；在反映早期肾损伤变化的方面，尿NAG较β2?MG更为敏感。

abstractsObjective To investigate dynamic change of cadmium body burden and renal dysfunction among residents living in cadmium?polluted areas. Methods From April to July of 2011, the cadmium?polluted areas of northern Guangdong province in China was chosen as the study site. Based on the levels of cadmium pollution in soil and rice, the survey areas were divided into low exposed group (average concentration of cadmium was 0.15-0.40 mg/kg, 0.5-1.0 mg/kg in rice and soil, respectively) and high exposed group (average concentration of cadmium was >0.40 mg/kg, >1.0 mg/kg in rice and soil, respectively). Stratified random sampling and cluster sampling method of epidemiological investigations were carried out among 414 local residents who lived in cadmium exposure areas for more than 15 years, aged above 40, and without occupational cadmium exposure, including 168 and 246 residents in low and high exposed group, respectively. From March to June of 2014, 305 respondents of those who participated in 2011 were successfully traced, including 116 and 189 respondents in low and high exposed group, respectively. We used health questionnaires to acquire their health status. Home?harvested rice and vegetable samples were collected using quartering method for detection of cadmium level, including 190 rice samples, 161 vegetable samples in 2011 and 190 rice samples, 153 vegetable samples in 2014. Urine specimens of residents were collected for the detection of urinary cadmium and creatinine as well as renal dysfunction biomarkers, namely, N?acetyl?beta?D?glucosamidase (NAG) andβ2?microglobulin (β2?MG), respectively. In 2011 and 2014, Chi?square test was used to investigate the differences of abnormality of cadmium concentration in rice, vegetables and urinary cadmium,β2?MG,and NAG that were expressed as odds ratio (OR) and 95%confidence intervals (95%CI). Results In 2011 and 2014, cadmium concentration P50 (P25-P75) in rice was 0.43 (0.17-1.10) mg/kg,and 0.42 (0.20-1.14) mg/kg, respectively (Z=-0.77, P=0.440). In 2011 and 2014, cadmium concentrations P50 (P25-P75) in vegetables were 0.13 (0.07-0.34) mg/kg,and 0.25 (0.12-0.59) mg/kg, respectively, with abnormal rates of 38.5%(62/161) and 60.8%(93/153), respectively. In 2014, both average concentration and abnormal rate of cadmium in vegetables were higher than those in 2011 (Z=-4.69,P<0.001 andχ2=15.58, P<0.001). Concentrations of urinary cadmium P50 (P25-P75) in high exposed group were 7.90 (3.96-14.91)μg/g creatinine, 8.64 (4.56-17.60)μg/g creatinine in 2011 and 2014, respectively. Contrary to that in 2011, urinary cadmium of high exposed group was significantly increased in 2014 (Z=-2.80 ,P=0.005). In 2011 and 2014, concentrations of β2?MG, NAG P50 (P25-P75) were 0.15 (0.07-0.29)μg/g creatinine, 0.15 (0.07-0.45)μg/g creatinine,and 7.12 (5.05-10.65) U/g creatinine, 13.55 (9.1-19.84) U/g creatinine, respectively, with abnormal rates of 7.5% (23/305), 15.1% (46/305) ,8.2%(25/305) , and 33.8% (103/305), respectively. Compared with baseline in 2011, average concentrations ofβ2?MG, NAG significantly increased in 2014 (Z=-2.263,P=0.024 and Z=-12.52,P<0.001), and abnormal rates ofβ2?MG, NAG were also higher in 2014 (χ2=15.61,P<0.001 andχ2=64.72,P<0.001), with odds ratio (OR) of 2.00 (95%CI:1.23-3.24) and 4.12 (95%CI:2.87-5.92). Conclusion Environmental cadmium pollution of crops such as rice and vegetables in survey areas continued to remain high. Body burden of cadmium might kept at sustainably high levels and renal dysfunction was worsened after continuous, long?term cadmium exposure. Our results suggested that NAG might be more sensitive than β2?MG to serve as an indicator for an individual's future tubular function.