ABSTRACT
Background Individual lead or cadmium exposure can cause abnormal blood glucose level and changes in telomere length, and the role of telomere length in the relationship between heavy metal joint exposure and blood glucose level is still unclear. Objective To explore the role of telomere length in the relationship between lead and cadmium coexposure and blood glucose. Methods A cross-sectional study was conducted. By convenient sampling method, 600 residents living in two communities in a city in North China were selected as participants from April to June 2016. Face-to-face interviews were performed to collect general demographics and lifestyles of the participants. The peripheral blood samples of the participants were collected for blood glucose and telomere length detection, the urine samples were collected for urinary cadmium, urinary lead, and urinary creatinine measurement, and both urinary cadmium and urinary lead were corrected by urinary creatinine. The included participants were divided into a control group, a high-cadmium and low-lead group, a high-lead and low-cadmium group, and a high-lead and high-cadmium group, according to the median levels of urinary cadmium and urinary lead. A restricted cubic spline model was constructed to analyze the relationship between urinary lead/cadmium levels and blood glucose concentrations in the four groups and the relationship between cadmium exposure and telomere length in the high-lead and high-cadmium group. Intermediary model test was conducted to analyze the effect of telomere length on the relationship between exposures to lead and cadmium and blood glucose. Results The included participants were divided into the control group (n=99), the high-cadmium and low-lead group (n=91), the high-lead and low-cadmium group (n=145), and the high-lead and high-cadmium group (n=265). The differences in age, education level, per capita monthly household income, smoking, blood glucose, and telomere length were statistically significant among the four groups (P＜0.05). The high-lead and high-cadmium group had the highest blood glucose concentration, (5.63±1.68) mmol·L−1, and the shortest telomere length, (2.63±1.05) Kb. The restricted cubic spline results showed that urinary cadmium level was correlated with blood glucose concentration in the high-lead and high-cadmium group (F=3.45, P=0.037), and there was a non-linear association (F=6.91, P=0.002); the association between urinary cadmium level and telomere length was also non-linear (F=5.93, P=0.043). The intermediary model test results showed that telomere length was a mediating variable between urinary cadmium level and blood glucose concentration, and the mediating effect size was 0.0192 (95%CI: 0.0007-0.0563), with a mediation ratio of 15.57%. Conclusion Correlations between urinary cadmium and blood glucose and between urinary cadmium and telomere length were observed in the high-lead and high-cadmium coexposure group, and telomere length may play a mediating role in the relationship between them.
ABSTRACT
Background Exposure to environmental lead can cause kidney damage and telomere wear. However, the relationship among lead, peripheral blood telomere length, and glomerular filtration rate (eGFR) are unclear. Objective This study is conducted to investigate the relationships of urinary lead level with peripheral blood telomere length and renal function index eGFR, and further explore whether peripheral blood telomere length plays an intermediary role in the relationship between urinary lead level and eGFR. Methods A case-control study was conducted to select 497 residents from two communities in a city, including 230 in the control group (eGFR≥80 mL·min−1) and 267 in the abnormal eGFR group (eGFR<80 mL·min−1). Basic information and health information of the subjects were collected through a face-to-face questionnaire survey. Fasting morning urine was collected, and urinary lead and urinary creatinine (UCr) were detected. Fasting peripheral venous blood was collected to detect telomere length and serum creatinine (SCr) in peripheral blood leukocytes. eGFR was estimated by the Levey formula. After further adjusting for age, gender, education level, family per capita monthly income, smoking, and drinking the relationship among urinary lead level, peripheral blood telomere length, and renal function index eGFR was evaluated by mediating effect analysis. Results The overall level of creatinine-adjusted urinary lead [M (P25, P75)] in the abnormal eGFR group was 3.85 (1.56, 7.34) μg·g−1 which was higher than that in the control group, 1.57 (0.60, 3.62) μg·g−1(P<0.001). In addition, the overall level of peripheral blood telomere length in the abnormal eGFR group was 2.42 (1.89, 3.10) Kb, lower than that in the control group, 2.69 (2.09, 3.64) Kb (P<0.001). The results of mediating effect analysis showed that the magnitude of mediating effect by peripheral blood telomere length was −0.276 (95%CI: −0.708-−0.001) and it contributed 3.35% to the relationship between urinary lead level and eGFR. In women, the magnitude of mediating effect by peripheral blood telomere length was −0.484 (95%CI: −1.160-−0.023) between urinary lead level and eGFR, and the proportion of the mediating effect was 5.34%. In men, no mediating role of peripheral blood telomere length was found between urinary lead and eGFR. Conclusion Urinary lead level is closely related to renal function index eGFR and telomere length in peripheral blood. Peripheral blood telomere length plays a mediating role in the relationship between female urinary lead and eGFR in women.
ABSTRACT
Objective To explore the relationship between environmental factors as urinary cadmium and type 2 diabetes mellitus (DM) in adults.Methods Case-control study was adopted,including 166 cases and 427 controls.General characteristics of the subjects were collected by a structured questionnaire.FPG,biochemical indexes and urinary cadmium (UCd) were detected respectively,while UCd was corrected with creatinine.Unconditioned logistic regression model was applied to analyze the relationship between UCd and DM.Results Levels of UCd appeared higher in cases with the following characteristics as:having primary school education (P=0.016),being female (P=0.013),being non-smokers (P=0.014) or non-alcoholic (P=0.025),and with BMI＞25.00 kg/m2 (P=0.040,P=0.025) than those appeared in the control group.Same results were shown in the 60-69 years (P=0.024) old group.Data from the unconditional logistic regression analysis showed that family history of DM (OR=3.19,95％ CI:1.45-7.03),education status (OR=1.50,95％CI:1.08-2.08) and UCd (OR=1.61,95％CI:1.08-2.41) were influencing factors on DM.Conclusion A close association between UCd and DM was noticed.UCd appeared a risk factor on DM that called for setting up related prevention program to reduce the exposure of Cd and to control the risk on DM.
ABSTRACT
Objective To explore the relationship between environmental factors as urinary cadmium and type 2 diabetes mellitus (DM) in adults.Methods Case-control study was adopted,including 166 cases and 427 controls.General characteristics of the subjects were collected by a structured questionnaire.FPG,biochemical indexes and urinary cadmium (UCd) were detected respectively,while UCd was corrected with creatinine.Unconditioned logistic regression model was applied to analyze the relationship between UCd and DM.Results Levels of UCd appeared higher in cases with the following characteristics as:having primary school education (P=0.016),being female (P=0.013),being non-smokers (P=0.014) or non-alcoholic (P=0.025),and with BMI＞25.00 kg/m2 (P=0.040,P=0.025) than those appeared in the control group.Same results were shown in the 60-69 years (P=0.024) old group.Data from the unconditional logistic regression analysis showed that family history of DM (OR=3.19,95％ CI:1.45-7.03),education status (OR=1.50,95％CI:1.08-2.08) and UCd (OR=1.61,95％CI:1.08-2.41) were influencing factors on DM.Conclusion A close association between UCd and DM was noticed.UCd appeared a risk factor on DM that called for setting up related prevention program to reduce the exposure of Cd and to control the risk on DM.
ABSTRACT
Objective To investigate the effects of mitochondrial DNA (mtDNA) copy number in peripheral blood and related factors on the risk of hypertension in coal miners.Methods A case-control study was conducted in 378 coal miners with hypertension and 325 healthy coal miners recruited from Datong Coal Mine Group.A standard questionnaire was used to collect their general information,such as demographic characteristics,habits and occupational history.Fluorescence quantitative PCR was performed to detect the copy number of mtDNA.Logistic regression model was applied for identifying the related risk factors of hypertension and analyzing the interaction between mtDNA copy number and risk factors.Results The prevalence of hypertension of high mtDNA copy number was lower than mtDNA copy numberin 0-5.67 group,but the difference was not statistically significant (P=0.414).Alcohol drinking (OR=1.80,95％CI:1.26-2.56),family history of hypertension (OR=1.74,95％ CI:1.20-2.50),work shifts (OR=0.69,95％ CI:0.48-0.99),education level (P=0.012) and family monthly income level (P=0.001) were related to the prevalence of hypertension.There were potential interactions between mtDNA copy number and alcohol drinking,family monthly income level,family history of hypertension,respectively.Alcohol drinking was a risk factor for hypertension [1.77(1.25-2.50)].Potential interactions between mtDNA copy number and alcohol drinking reduced the risk of hypertension (OR=1.20,95％CI:1.07-1.35).Family history of hypertension was a risk factor for hypertension [1.81(1.26-2.59)].Potential interactions between mtDNA copy number and family history of hypertension reduced the risk of hypertension (OR=1.24,95％ CI:1.09-1.41).Family monthly income level was a protect factor for hypertension [0.55(0.46-0.66)].Potential interactions between mtDNA copy number and family monthly income level increased the protection role of hypertension (OR=0.90,95％CI:0.86-0.94).Conclusion mtDNA copy number variation was not significantly associated with the prevalence of hypertension in coal miners,but mtDNA copy number shewed multiplication interaction on the prevalence of hypertension with alcohol drinking,family monthly income level as well as family history of hypertension and made their influences weaken.
ABSTRACT
Objective To investigate the effects of mitochondrial DNA (mtDNA) copy number in peripheral blood and related factors on the risk of hypertension in coal miners.Methods A case-control study was conducted in 378 coal miners with hypertension and 325 healthy coal miners recruited from Datong Coal Mine Group.A standard questionnaire was used to collect their general information,such as demographic characteristics,habits and occupational history.Fluorescence quantitative PCR was performed to detect the copy number of mtDNA.Logistic regression model was applied for identifying the related risk factors of hypertension and analyzing the interaction between mtDNA copy number and risk factors.Results The prevalence of hypertension of high mtDNA copy number was lower than mtDNA copy numberin 0-5.67 group,but the difference was not statistically significant (P=0.414).Alcohol drinking (OR=1.80,95％CI:1.26-2.56),family history of hypertension (OR=1.74,95％ CI:1.20-2.50),work shifts (OR=0.69,95％ CI:0.48-0.99),education level (P=0.012) and family monthly income level (P=0.001) were related to the prevalence of hypertension.There were potential interactions between mtDNA copy number and alcohol drinking,family monthly income level,family history of hypertension,respectively.Alcohol drinking was a risk factor for hypertension [1.77(1.25-2.50)].Potential interactions between mtDNA copy number and alcohol drinking reduced the risk of hypertension (OR=1.20,95％CI:1.07-1.35).Family history of hypertension was a risk factor for hypertension [1.81(1.26-2.59)].Potential interactions between mtDNA copy number and family history of hypertension reduced the risk of hypertension (OR=1.24,95％ CI:1.09-1.41).Family monthly income level was a protect factor for hypertension [0.55(0.46-0.66)].Potential interactions between mtDNA copy number and family monthly income level increased the protection role of hypertension (OR=0.90,95％CI:0.86-0.94).Conclusion mtDNA copy number variation was not significantly associated with the prevalence of hypertension in coal miners,but mtDNA copy number shewed multiplication interaction on the prevalence of hypertension with alcohol drinking,family monthly income level as well as family history of hypertension and made their influences weaken.