Objective To understand the situation of cancer screening of community residents and its association with the knowledge of cancer core knowledge, and to provide reference for the formulation of secondary cancer prevention measures. Methods A cross-sectional survey was conducted among 2 037 residents aged 18-79 who lived in Bao 'an District, Shenzhen. Multivariate Logistic regression analysis was used to investigate the relationship between core knowledge and cancer screening behavior after adjusting for age, gender, education, marriage, occupation and smoking. Results The cancer screening rate of community residents was 28.10%, and the screening rate of middle-aged and elderly people aged 40-79 was 33.50 %.The proportion of ^“not very well understanding^”, ^“partial understanding^” and ^“basic understanding^” of the core knowledge of cancer were 43.91%, 42.33% and 13.76%, respectively, which was higher than that of the non-participants. Multivariate analysis showed that the women, the higher the level of education of college/university or above and the higher the level of knowledge of cancer prevention core knowledge, the higher the probability of participating in cancer screening was OR (95%CI ) : 2.40 (1.86-3.12), 1.65 (1.29-2.10), 1.38 (1.18 - 1.62), respectively. Conclusion The proportion of cancer screening in community residents needs to be improved, and the degree of core knowledge of cancer is closely related to cancer screening behavior. It is suggested to increase the publicity and education of the core knowledge of cancer, and at the same time, carry out the health education of secondary cancer prevention for the key population such as men and people with low education level, so as to improve the proportion of ^“early detection, early diagnosis and early treatment^” of cancer.

To explore the mechanism for changes in brain microstructure in long-term abstinent from methamphetamine-dependence by using the diffusion tensor imaging (DTI).
 Methods: A total of 26 patients with long-term abstinent methamphetamine-dependence, whose abstinence time more than 14 months, and 26 normal controls all underwent cognitive executive function tests and DTI scans. We used voxel-based analysis to compare the fractional anisotropy (FA) and mean diffusivity (MD) to obtain the abnormal brain regions of DTI parameters between the two groups. Spearman correlation analysis was used to explore the correlation between FA, MD of the brain regions with abnormal parameters and cognitive executive function tests.
 Results: There were no statistical differences in the cognitive executive function tests between the two groups (P>0.05). Compared with the normal control group, the long-term abstinent from methamphetamine-dependence group showed the decreased FA in the right precuneus, right superior frontal gyrus, right calcarine, left inferior temporal gyrus and the increased MD in the right triangular part of inferior frontal gyrus, right precuneus, right posterior cingulate, right middle temporal gyrus, bilateral middle occipital gyrus, left superior parietal lobule, and lobule VIII of cerebellar hemisphere. The MD values of the right middle temporal gyrus in the long-term abstinent group were negatively correlated with the number of completions within 60 seconds (r=-0.504) and within 120 seconds (r=-0.464) .
 Conclusion: The DTI parameters in multiple brain regions from the methamphetamine-dependence patients are still abnormal after a long-term abstinence. DTI can provide imaging evidence for brain microstructural abnormalities in long-term abstinent from methamphetamine-dependence.
Amphetamine-Related Disorders ; Anisotropy ; Brain ; Diffusion Tensor Imaging ; Humans ; Methamphetamine

Objective To observe the objective response rate, survival and safety of radiotherapy combined with Iressa for patients with locally advanced non-small cell lung cancer ( NSCLC) unsuitable for surgery or concurrent chemoradiotherapy. Methods The patients with locally advanced NSCLC unsuitable for surgery or concurrent chemoradiotherapy were recruited and received thoracic intensity-modulated radiotherapy ( IMRT) combined with Iressa 250 mg daily. Results A total of 30 patients were enrolled between July 2014 and March 2017. Twenty-nine patients were analyzed. At 1 month after radiotherapy,the complete response (CR) was 0,partial response (PR) was 21(72％),stable disease (SD) was 6(21％), progressive disease (PD) was 2(7％),the disease control rate (CR+PR+SD) was 93％,and the objective response rate was 72％. The median follow-up time was 25 months. Fourteen ( 48％) patients died,and 15 (52％) survived. Twenty-three (79％) patients obtained PD including local progression in 18(62％) and distant metastasis in 14(48％). The median survival time (MST) was 26 months and the median PFS was 11 months. The 1-year OS and PFS were 79％ and 44％,and the 2-year OS and PFS were 55％ and 18％. Univariate analysis demonstrated that smoking history and disease stage were influencing factors for OS ( P=0. 035,0. 031) . Moreover, disease stage, the primary tumor diameter, the volume of GTV and PTV were influencing factors for PFS (P=0. 000,0. 016,0. 039,0. 030). Multivariable analysis revealed that disease stage and the volume of PTV were independent prognostic factors for PFS (P=0. 000,0. 012).Two patients ( 7％) developed grade 3 acute adverse events and 7 ( 24％) experienced grade 2 acute irradiation pneumonitis. Conclusions For patients with locally advanced NSCLC unsuitable for surgery or concurrent chemoradiotherapy,IMRT combined with Iressa yields high objective response rate and well tolerance. The long-term clinical efficacy remains to be validated.

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.

OBJECTIVETo study long-term effect on renal function exposed to environmental cadmium.

METHODSStratified random sampling and cluster sampling method of epidemiological investigations were carried out in northern Guangdong province between April, 2011 and August, 2012. A total of 167 residents who lived in high cadmium exposure area for more than 15 years, aged above 40 were selected in exposed group. Moreover, A total of 145 residents who had similar living and economic conditions and lived in local for more than 15 years, aged above 40 were selected in control group. We used health questionnaires and medical examinations in order to acquire their health status. Home-harvested rice and vegetables were collected using quartering method for detection of cadmium level. Urine specimens of residents were collected for detection of cadmium level and creatinine as well as renal dysfunction biomarkers, namely, N-acetyl-beta-D-glucosamidase (NAG), β2-microglobulin (β2-MG), and retinol binding protein(RBP), respectively. The analysis of spearman rank correlation and multiple regression were used to investigate the relationships between age, urinary cadmium levels and renal injury biomarkers.

RESULTSThe cadmium levels in rice and vegetables of exposed group were 0.75 and 0.10 mg/kg, both were significantly higher than 0.07 and 0.01 mg/kg in the control group (Z values were -6.32 and -7.84, all P values < 0.001). The urinary cadmium level of exposed group was 8.29 µg/g · cr, which was higher than that of the control group 2.03 µg/g · cr with significant difference (Z value was -11.39, P < 0.001). After stratified the total population by age, the urinary cadmium level in 40-49 years, 50-59 years and ≥ 60 years subgroups were 7.22, 8.71, and 13.10 µg/g · cr, which both were significantly higher than 1.80, 2.04, and 2.05 µg/g · cr in the control group (Z values were -5.22, -7.41, and -7.14, all P values < 0.001). After stratified the total population by gender, the urinary cadmium level of male and female were 5.12 and 12.36 µg/g · cr, which both were significantly higher than 1.79 and 2.16 µg/g · cr in the control group (Z values were -7.68 and -9.03, all P values < 0.001). Comparing the differences of renal dysfunction biomarkers (NAG, β2-MG, RBP) between two groups. The level of urinary β2-MG and RBP of exposed group were 0.21 and 0.04 µg/g · cr, which were higher than 0.05 and 0.00 µg/g · cr of the control group with significant difference (Z value was -7.08 and -9.65, all P values < 0.001). Pearson correlation analysis showed that NAG, β2-MG and RBP were positively correlated with urinary cadmium and age, the correlation coefficients were 0.57, 0.49, 0.21 and 0.22, 0.26, 0.23 respectively (all P values < 0.001). After adjusting the effect of age, it was appeared that urinary cadmium levels contributed most to the alteration of NAG, β2-MG and RBP, the standardized regression coefficients were 0.57, 0.49 and 0.20 (all P values < 0.001), and suggested that the cadmium body burden was one of the most important factors for renal dysfunction.

CONCLUSIONResidents, who had cadmium contaminated rice and vegetables for a long time, would take the risk of increasing body burden of cadmium and urinary early biomarkers of renal tubular injury that referred to occurrence of renal dysfunction.

Adult ; Aged ; Cadmium ; Creatinine ; Environmental Exposure ; Epidemiologic Studies ; Female ; Food Contamination ; Humans ; Kidney Diseases ; Male ; Middle Aged ; Multivariate Analysis ; Oryza ; Risk ; Time ; Vegetables

Objective To study long-term effect on renal function exposed to environmental cadmium. Methods Stratified random sampling and cluster sampling method of epidemiological investigations were carried out in northern Guangdong province between April, 2011 and August, 2012 . A total of 167 residents who lived in high cadmium exposure area for more than 15 years, aged above 40 were selected in exposed group. Moreover, A total of 145 residents who had similar living and economic conditions and lived in local for more than 15 years, aged above 40 were selected in control group. We used health questionnaires and medical examinations in order to acquire their health status. Home-harvested rice and vegetables were collected using quartering method for detection of cadmium level . Urine specimens of residents were collected for detection of cadmium level and creatinine as well as renal dysfunction biomarkers, namely, N-acetyl-beta-D-glucosamidase(NAG), β2-microglobulin(β2-MG), and retinol binding protein(RBP), respectively. The analysis of spearman rank correlation and multiple regression were used to investigate the relationships between age, urinary cadmium levels and renal injury biomarkers. Results The cadmium levels in rice and vegetables of exposed group were 0.75 and 0.10 mg/kg, both were significantly higher than 0.07 and 0.01 mg/kg in the control group (Z values were-6.32 and-7.84, all P values<0.001). The urinary cadmium level of exposed group was 8.29μg/g·cr, which was higher than that of the control group 2.03μg/g·cr with significant difference(Z value was-11.39, P<0.001). After stratified the total population by age, the urinary cadmium level in 40-49 years, 50-59 years and≥60 years subgroups were 7.22, 8.71, and 13.10μg/g·cr, which both were significantly higher than 1.80, 2.04, and 2.05μg/g·cr in the control group (Z values were-5.22,-7.41, and-7.14, all P values<0.001). After stratified the total population by gender , the urinary cadmium level of male and female were 5.12 and 12.36μg/g · cr, which both were significantly higher than 1.79 and 2.16 μg/g · cr in the control group (Z values were-7.68 and-9.03, all P values<0.001). Comparing the differences of renal dysfunction biomarkers (NAG, β2-MG, RBP) between two groups. The level of urinaryβ2-MG and RBP of exposed group were 0.21 and 0.04μg/g · cr, which were higher than 0.05 and 0.00 μg/g · cr of the control group with significant difference(Z value was-7.08 and-9.65, all P values<0.001). Pearson correlation analysis showed that NAG,β2-MG and RBP were positively correlated with urinary cadmium and age, the correlation coefficients were 0.57,0.49,0.21and 0.22, 0.26, 0.23 respectively (all P values<0.001). After adjusting the effect of age, it was appeared that urinary cadmium levels contributed most to the alteration of NAG, β2-MG and RBP, the standardized regression coefficients were 0.57, 0.49 and 0.20 (all P values<0.001), and suggested that the cadmium body burden was one of the most important factors for renal dysfunction. Conclusion Residents, who had cadmium contaminated rice and vegetables for a long time, would take the risk of increasing body burden of cadmium and urinary early biomarkers of renal tubular injury that referred to occurrence of renal dysfunction.

Objective To study long-term effect on renal function exposed to environmental cadmium. Methods Stratified random sampling and cluster sampling method of epidemiological investigations were carried out in northern Guangdong province between April, 2011 and August, 2012 . A total of 167 residents who lived in high cadmium exposure area for more than 15 years, aged above 40 were selected in exposed group. Moreover, A total of 145 residents who had similar living and economic conditions and lived in local for more than 15 years, aged above 40 were selected in control group. We used health questionnaires and medical examinations in order to acquire their health status. Home-harvested rice and vegetables were collected using quartering method for detection of cadmium level . Urine specimens of residents were collected for detection of cadmium level and creatinine as well as renal dysfunction biomarkers, namely, N-acetyl-beta-D-glucosamidase(NAG), β2-microglobulin(β2-MG), and retinol binding protein(RBP), respectively. The analysis of spearman rank correlation and multiple regression were used to investigate the relationships between age, urinary cadmium levels and renal injury biomarkers. Results The cadmium levels in rice and vegetables of exposed group were 0.75 and 0.10 mg/kg, both were significantly higher than 0.07 and 0.01 mg/kg in the control group (Z values were-6.32 and-7.84, all P values<0.001). The urinary cadmium level of exposed group was 8.29μg/g·cr, which was higher than that of the control group 2.03μg/g·cr with significant difference(Z value was-11.39, P<0.001). After stratified the total population by age, the urinary cadmium level in 40-49 years, 50-59 years and≥60 years subgroups were 7.22, 8.71, and 13.10μg/g·cr, which both were significantly higher than 1.80, 2.04, and 2.05μg/g·cr in the control group (Z values were-5.22,-7.41, and-7.14, all P values<0.001). After stratified the total population by gender , the urinary cadmium level of male and female were 5.12 and 12.36μg/g · cr, which both were significantly higher than 1.79 and 2.16 μg/g · cr in the control group (Z values were-7.68 and-9.03, all P values<0.001). Comparing the differences of renal dysfunction biomarkers (NAG, β2-MG, RBP) between two groups. The level of urinaryβ2-MG and RBP of exposed group were 0.21 and 0.04μg/g · cr, which were higher than 0.05 and 0.00 μg/g · cr of the control group with significant difference(Z value was-7.08 and-9.65, all P values<0.001). Pearson correlation analysis showed that NAG,β2-MG and RBP were positively correlated with urinary cadmium and age, the correlation coefficients were 0.57,0.49,0.21and 0.22, 0.26, 0.23 respectively (all P values<0.001). After adjusting the effect of age, it was appeared that urinary cadmium levels contributed most to the alteration of NAG, β2-MG and RBP, the standardized regression coefficients were 0.57, 0.49 and 0.20 (all P values<0.001), and suggested that the cadmium body burden was one of the most important factors for renal dysfunction. Conclusion Residents, who had cadmium contaminated rice and vegetables for a long time, would take the risk of increasing body burden of cadmium and urinary early biomarkers of renal tubular injury that referred to occurrence of renal dysfunction.