Objective To investigate the effect of long?term exposure to environmental cadmium on eight mineral element's metabolic balance of human body. Methods To choose a high cadmium area polluted by smelting and mining north of Guangdong province and a cadmium?free area with a similar economic level, and living and eating habit of residents as a contrast from April 2011 to August 2012. Stratified random sampling and clustered sampling method were adopted to choose the non?occupationally cadmium?exposed respondents who have lived in local area for more than 15 years, older than 40 years, having local rice and vegetable as the main dietary source, with simple and relatively stable diet, and without diabetes, kidney disease, thyroid disease, liver disease or other history of chronic disease. This study included 298 respondents, of whom 155 were in cadmium exposure group and 143 in control group. Questionnaires was used to acquire their health status and their morning urine samples were collected. Electrolytically coupled plasma mass spectrometry (ICP?MS) was used to test the concentrations of sodium (Na), magnesium (Mg), phosphorus (P), potassium (K), calcium (Ca), copper (Cu), zinc (Zn) and iodine (I). The Mann?Whitney U test method was used to compare the differences of concentrations of urinary cadmium, Na, Mg, P, K, Ca, Cu, Zn, I, and the ratio of Na to K (Na/K), Ca to P (Ca/P) between exposed group and control group.χ2 test was used to compare the abnormal rate of urinary cadmium between exposed group and control group. Pearson correlation and multiple regression method were used to investigate the relationship between urinary cadmium levels, gender, age, smoking, passive smoking, and minerals. Results The urinary cadmium level P50 (P25-P75) in exposed group was 5.45 (2.62-10.68)μg/g·cr, which was higher than that of the control group, which was 1.69 (1.22-2.36)μg/g · cr (Z=-10.49, P<0.001). The abnormal rate of urinary cadmium was 51.6%(80/155), which was higher than that of the control group (2.8%(4/143)) (χ2=87.56,P<0.001). The urinary Ca, Cu, Zn, and I level P50 (P25-P75) of exposed group were 173.80 (114.40-251.70), 20.55 (14.95-28.44), 520.23 (390.25-647.15), and 246.94 (203.65-342.97)μg/g · cr, which were higher than those in control group (142.42 (96.87-179.11), 15.44 (12.26-20.98), 430.09 (309.85-568.78) and 213.85 (156.70-281.63) μg/g · cr, respectively) (Z values were-4.33,-5.04,-3.47 and-4.24, all P values<0.001). The urinary P, K level P50 (P25-P75) of exposed group were 582.50 (463.20-742.8), 890.10 (666.00-1 305.40) μg/g · cr, which were lower than control group (694.50 (546.20-851.17), 1 098.58 (904.53-1 479.18) μg/g · cr) (Z values were-3.36,-4.02, all P values <0.001). on Based the results of Pearson correlation analysis, urinary cadmium was positively correlated with urinary Ca, Cu, Zn, and I, and the correlation coefficients were 0.31, 0.61, 0.38, and 0.25, respectively(all P values<0.05). Based on the results of multiple regression analysis, urinary cadmium levels contributed most to the metabolic balance of urinary Ca, Cu, Zn and I. The standardized regression coefficients were 0.31, 0.59, 0.39, and 0.24, respectively (all P values<0.001). Conclusion Long?term environmental exposure to cadmium affected the metabolic balance of Ca, Cu, Zn and I in human body.

Objective 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.

Objective To investigate the effect of long?term exposure to environmental cadmium on eight mineral element's metabolic balance of human body. Methods To choose a high cadmium area polluted by smelting and mining north of Guangdong province and a cadmium?free area with a similar economic level, and living and eating habit of residents as a contrast from April 2011 to August 2012. Stratified random sampling and clustered sampling method were adopted to choose the non?occupationally cadmium?exposed respondents who have lived in local area for more than 15 years, older than 40 years, having local rice and vegetable as the main dietary source, with simple and relatively stable diet, and without diabetes, kidney disease, thyroid disease, liver disease or other history of chronic disease. This study included 298 respondents, of whom 155 were in cadmium exposure group and 143 in control group. Questionnaires was used to acquire their health status and their morning urine samples were collected. Electrolytically coupled plasma mass spectrometry (ICP?MS) was used to test the concentrations of sodium (Na), magnesium (Mg), phosphorus (P), potassium (K), calcium (Ca), copper (Cu), zinc (Zn) and iodine (I). The Mann?Whitney U test method was used to compare the differences of concentrations of urinary cadmium, Na, Mg, P, K, Ca, Cu, Zn, I, and the ratio of Na to K (Na/K), Ca to P (Ca/P) between exposed group and control group.χ2 test was used to compare the abnormal rate of urinary cadmium between exposed group and control group. Pearson correlation and multiple regression method were used to investigate the relationship between urinary cadmium levels, gender, age, smoking, passive smoking, and minerals. Results The urinary cadmium level P50 (P25-P75) in exposed group was 5.45 (2.62-10.68)μg/g·cr, which was higher than that of the control group, which was 1.69 (1.22-2.36)μg/g · cr (Z=-10.49, P<0.001). The abnormal rate of urinary cadmium was 51.6%(80/155), which was higher than that of the control group (2.8%(4/143)) (χ2=87.56,P<0.001). The urinary Ca, Cu, Zn, and I level P50 (P25-P75) of exposed group were 173.80 (114.40-251.70), 20.55 (14.95-28.44), 520.23 (390.25-647.15), and 246.94 (203.65-342.97)μg/g · cr, which were higher than those in control group (142.42 (96.87-179.11), 15.44 (12.26-20.98), 430.09 (309.85-568.78) and 213.85 (156.70-281.63) μg/g · cr, respectively) (Z values were-4.33,-5.04,-3.47 and-4.24, all P values<0.001). The urinary P, K level P50 (P25-P75) of exposed group were 582.50 (463.20-742.8), 890.10 (666.00-1 305.40) μg/g · cr, which were lower than control group (694.50 (546.20-851.17), 1 098.58 (904.53-1 479.18) μg/g · cr) (Z values were-3.36,-4.02, all P values <0.001). on Based the results of Pearson correlation analysis, urinary cadmium was positively correlated with urinary Ca, Cu, Zn, and I, and the correlation coefficients were 0.31, 0.61, 0.38, and 0.25, respectively(all P values<0.05). Based on the results of multiple regression analysis, urinary cadmium levels contributed most to the metabolic balance of urinary Ca, Cu, Zn and I. The standardized regression coefficients were 0.31, 0.59, 0.39, and 0.24, respectively (all P values<0.001). Conclusion Long?term environmental exposure to cadmium affected the metabolic balance of Ca, Cu, Zn and I in human body.

Objective 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.