| Objective:The aim of the study was to evaluate the level of chronic cadmium (Cd)exposure using urine cadmium (UCd), and the association between UCd leveland blood pressure in the Guigang general population, Guangxi. The findingscan provide us epidemiological evidence on Cd exposure, additionally, estimatethe potential effect of chronic low-level Cd exposure on blood pressure in theGuangxi general population.Methods:1. The current study based on cross-sectional design.1035adult residentswith age over20years old were enrolled from seven administrative villages andone center community in Jintian town and Shika town, Guigang by two stagestratified cluster sampling. First, we used the self-designed questionnaire tosurvey the study participants’ basic demographic information, drinking water,eating habits, smoking, drinking, disease and taking drugs. Second, the studyparticipants’ height, weight, blood pressure and rapid glycemic were measured.To collect the study participants’ urine sample for testing UCd and urine creatinine. The UCd level in different characteristics was estimated bystratifying with overall and gender.2. We estimated the effects of drinking water, eating organ meats, eatingshrimp, crab, shellfish, eating fish, cooking oil and smoking on UCd level byusing multivariate linear regression, respectively; And to use simple andmultivariate linear regression for exploring risk factors of UCd in generalpopulation, respectively; Using multi-level model to analysis the differences ofUCd in urban, suburban and rural areas. The above analyses were stratified bygender.3. The UCd was divided into four equal portions by using the quartilemethod. We compared the2ed,3rd,4th decile of UCd with the first decile andestimated the changes in systolic blood pressure (SBP), diastolic blood pressure(DBP) through multiple linear regression; And used Logistic regression tocompare the2ed,3rd,4th decile of UCd to the first decile and estimated the riskodds ratio (OR) of hypertension; In addition, we further explored the interactionanalyses of UCd level on the risk of hypertension in subgroups of age, education,income, menopause, eating shrimp, crab, shellfish, eating organ meats, smoking,drinking, BMI and diabetes mellitus. The P value of the subgroups analysis wasobtained from Wald test. The statistical description and analyses of the studyused to weighted estimation method with the study samples weights exceptmulti-level models.Results:1. The UCd level of general population(1) The UCd horizontal rang of1035study participants was from0.002to2.915μg/g creatinine. The UCd geometric mean value was0.15μg/g creatinine and the95%confidence interval was from0.10to0.21μg/g creatinine of studypopulation. The UCd geometric mean value was0.13μg/g creatinine and the95%confidence interval was from0.09to0.19μg/g creatinine of men and theUCd geometric mean value was0.17μg/g creatinine and the95%confidenceinterval was from0.12to0.23μg/g creatinine of women.(2)The UCd geometric mean value and95%confidence interval of studyparticipants with aged20to39years were0.12μg/g creatinine and from0.07to0.21μg/g creatinine, aged40to59years were0.16μg/g creatinine and from0.12to0.22μg/g creatinine) and aged60years or older were0.17μg/gcreatinine and from0.13to0.22μg/g creatinine.2. The risk factors of UCd level(1) For the six direct exposed factors, after adjusting all covariates, it notfound the exposed factors significantly influenced UCd level in men (P>0.05).While the UCd geometric mean of drinking well water was21%lower than thegroups of drinking tap water (P=0.016) in women.(2) In terms of risk factors, there was not found the exposed factorssignificantly influenced UCd level in men (P>0.05); But in women, the twofactors of drinking well water (β=-1.25，P=0.005) and eating fish1to3timesper month (β=-1.17，P=0.027) were association witn reducing UCd level.(3) In terms of exploring of UCd level in different regions, after adjustingsix direct exposed factors and other covariates, there were gender differences ofUCd level in regions. And the UCd level in urban was lower than suburban andrural areas in men, while the UCd level in urban was higher than suburban andrural areas in women.3. The relationship between UCd level and blood pressureIt showed no significant relationship of linear trend (Ptrend>0.05) between UCd level and blood pressure in both men and women. For men, after adjustingall covariates and compared the highest UCd to the lowest decile, the changes inSBP, DBP and the risk of OR to hypertension were2.6mmHg (95%CI:-2.9~8.0mmHg),2.3mmHg (95%CI:-1.6~6.1mmHg) and0.34(95%CI:0.09~1.22); For women, after adjusting all covariates and comparing the highestUCd to the lowest decile, the changes in SBP, DBP and the risk of OR tohypertension were-5.1mmHg (95%CI:-13.6~3.5mmHg),-1.4mmHg (95%CI:-5.0~2.2mmHg) and1.37(95%CI:0.91~2.05). In the analyses of exploringinteraction, there was no significant interaction of UCd level on the risk ofhypertension in subgroups analysis both in men and women (P>0.05).Conclusion:1. The current status of chronic Cd exposure of general population inGuigang, Guangxi were as follws: The geometric mean value of UCd level was0.15μg/g creatinine (95%CI:0.10,0.21μg/g creatinine) and it was a low-level.It was lower than the present safety standards. Generally, the UCd level ofwomen was higher than men and it increased with age. The risk factors of UCdin low-level was not significant in men. However, in women, drinking wellwater would reduce UCd level. Besides, there were significant regionaldifferences of UCd in low-level between different genders.2. When the geometric mean value of UCd was0.15μg/g creatinine and95%CI was from0.10to0.21μg/g creatinine, there was no relationshipbetween chronic low-level Cd exposure and blood pressure.. This suggests that ithas no elevated effects of the chronic low-level Cd exposure on blood pressureof general population in the above dosage range and it failed to reach the riskthreshold of increasing blood pressure. |
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