| Objectives1. To investigate the serum levels and distribution characteristics of iron, copper, zinc, patassium, sodium, calcium, magnesium, etc. in the population of Pingyin.2. To analysis the correlation between serum levels of seven kinds of elements and chronic diseases such as hypertension, hyperlipidemia and coronary heart disease.3. To discuss the relationship between serum levels of iron, copper, zinc, potassium, sodium, calcium, magnesium and common chronic diseases such as hypertension, hyperlipidemia and coronary heart disease.4. To analysis the various influence factors of the serum levels of elements and several chronic diseases, such as age, gender, personal behaviors and the level of elements intake.5. To reveal the inherent relationship between the serum levels and distribution characteristics of iron, copper, zinc, potassium, sodium, calcium, magnesium and chronic diseases such as hypertension, hyperlipidemia and coronary heart disease.Methods1. Investigation All permanent residents of five villages drawn from Pingyin with cluster sampling were investigated. Household survey was selected to investigate.2. Physical examinations and blood sampling Meanwhile, physical examinations including height, weight, blood pressure and other physiological indicators were checked and blood samples were collected.3mL of anticoagulant blood was centrifuged with1000rpm for5to10minutes, and the serum was placed into eppeddorf tubes. Then the tubes were numbered, transported and kept in low temperature.3. Determination of serum samples The methods to determined serum levels of elements by flame atomic absorption spectrophotometric in defined instrument conditions and sample processing were tested. The detection limits, precisions including inter-day precision and intra-day precision, relative error and add mark recovery rates were calculated and assessed. After processed, the serum samples were determined for levels of elements by atomic absorption spectrophotomety. The serum concentration of elements could be calculated by multiplying the dilution factors.4. Determination of serum lipid Total cholesterol, triglycerides, high density lipoprotein-cholesterol of serum were determinated with TC kit, TG kit and HDL-C kit according to their determination conditions and steps. The serum level of lowdensity lipoprotein-cholesterol was calculated indirectly.5. Quality control was required to be done from investigation and sampling to determination of laboratory indicators and data entrying. Selection principle of respondents was confirmed before the survey. Then quality control was also done along with the investigation, phyisical examination and samples collecting. The laboratory indicators were determined within the acceptable range of laboratory variation. A control serum was determined per30samples as determination of blood biochemical and a standard solutions was determined per50samples as determination of serum trace elements.6. Data processing A database was established and the data from experiment and survey was entried. And then the required data was statistically processed. Statistical software of SAS9.1was used and the data was presented as mean+standard deviation(x±s). The used statistical approaches included independent samples t test, chi-square test, analysis of variance, simple correlation, non-conditional logistic multiple regression analysis. It was considered statistically significant if P<0.05.Results1. The methods to determine serum levels of elements by flame atomic absorption spectrophotometric in defined instrument conditions and sample processing were tested. The results showed that this method could meet the demand of serum elements determination. The detection limits of Cu, Fe, Zn, K, Na, Ca, Mg were0.02mg/L,0.03mg/L,0.01mg/L,0.05mg/L,0.10mg/L,0.05mg/L,0.004mg/L. The inter-day precisons of Cu, Fe, Zn, K, Na, Ca, Mg were0.97%,1.06%,1.89%,3.24%,0.91%,2.09%,1.84%. The intra-day precisons of Cu, Fe, Zn, K, Na, Ca, Mg were3.22%,3.79%,3.95%,5.23%,3.12%,4.17%,5.25%. All of them were below10%. The mean relative errors of Cu, Fe, Zn, K, Na, Ca, Mg were2.35%,2.95%,7.10%,7.23%,9.37%,2.08%,8.90%. The add mark recovery rates of each element were in85%-110%.2. The levels and distribution characteristics of serum elements in the population of Pingyin were as follows:Cu1.20±0.35mg/L, Fe1.54±0.74mg/L, Zn1.41±0.47mg/L, K211.61±35.45mg/L, Na3.27±0.45g/L, Ca109.88±25.65mg/L, and Mg29.49±7.82mg/L After oneway ANOVA among different genders and different ages, it was found that the older age, the higher serum level of copper. Copper level of female group was higher than that of same age male group. The serum level of copper was different among different ages and genders. There was an increasing tendency of serum iron and its level of female group was lower than that of same age male group. It was also found that there was a significantly decreasing tendency among serum levels of zinc of male group,while the female group was not found that. The serum levels of zinc of young male group was higher than that of same age female group. While that of old male group was lower than the same age female group. There was no age and gender differences in levels of serum K, Na, Ca, Mg and it might not be related to age and gender.3. After independent samples t test, it was statistical differences in age, weight, BMI, TG, TC, LDL-C and HDL-C between hypertension patients group and the control group. The average age, weight, BMI of the hypertension patients group were significantly higher than that of the control group. And the levels of serum TG, TC and LDL-C were also higher than that of control group. Analysis of the the sex ratio, drinking rate, smoking rate, drinking tea rate of the two group with chi-square test, it was found that male patients accounted for45.90%of the hypertension group, while35.56%of the control group. It was indicated that there was less female hypertension patients than male. The drinking rate, smoking rate, drinking tea rate of the hypertension group were higher than that of the control group.4. After independent samples t test, it was statistical differences in serum levels of Cu and K between hypertension patients group and the control group. The serum levels of Cu of hypertension group was lower than that of the control group, while higher serum level of K. The serum levels of Zn was also lower than that of the control group and the whole population, but the difference was not statistically significant. The serum levels of Fe, Zn, Na, Ca and Mg of the two group were no significant differences.5. After simple correlation analysis between level of serum elements and blood pressure, it was found that there was weak correlation between serum levels of Cu, Fe, Mg and systolic blood pressure. The correlation coefficients was r=-0.0682,0.0619,0.0626. There was also weak correlation between serum levels of Fe, Zn and diastolic blood pressure. The correlation coefficient was r=0.0912,-0.0596. The correlation between serum levels of K, Na, Ca and blood pressure was not statistically significant.6. In addition to high age as the risk factor for hypertension, after logistic regression analysis between hypertension and serum levels of elements, smoking, drinking, genetic factors and other influencing factors, it was found that it was statistically significant between hypertension and BMI, serum levels of Cu, Zn, TG, TC, drinking behavior, genetic factors(P<0.05). High BMI, high TG and TC, drinking behavior, genetic factors were risk factors for hypertension.While trace elements Cu and Zn were protective factors for hypertension.7. Logistic regression analysis between hyperlipidemia and level of serum elements, smoking, drinking, genetic factors and other influencing factors, it was found that it was statistically significant between hyperlipidemia and age, BMI, serum level of Fe and K, drinking, drinking tea(P<0.05). High age, high BMI, high level of serum Fe, K, drinking behavior were risk factors for hyperlipidemia. While drinking tea was protective factor for hyperlipidemia.8. Logistic regression analysis between coronary heart disease and serum levels of elements, smoking, drinking, genetic factors and other influencing factors, it was found that old age, high serum level of K and high LDL-C were risk factors for coronary heart disease.9. Correlation analysis between serum levels of elements and the elements intake in dietary nutrition table, it was found that only element Cu showed a weak correlation, and the correlation coefficient r=0.0996. There was no correlation between other elements.Conclusions1. The methods to determined serum levels of elements by flame atomic absorption spectrophotometric were tested. The results showed this method could meet the demand of serum elements determination.2. The distribution characteristics of serum elements in the population of Pingyin were as follows:Cu0.51-1.89mg/L, Fe0.10-2.99mg/L, Zn0.49-2.33mg/L, K142.13-281.09mg/L, Na2.39-4.15g/L, Ca59.61-160.15mg/L, Mg14.16-44.82mg/L. There was an increasing tendency of serum copper and a same tendency was found in the serum level of iron of male patients. The serum level of copper of female patients was higher than male. While the serum level of iron of male patients was higher than female.Moreover, the serum levels of zinc of young male group was higher than that of same age female group. While that of old male group was lower than the same age female group.3. Weight, BMI, TC, TG, LDL-C, drinking rate, smoking rate, drinking tea rate of hypertension patients were higher than common. The incidence was increasing with age. The serum level of K was higher in hypertension patients, while levels of Cu was lower.4. High BMI, high TC and TG, drinking behavior, genetic factors were risk factors for hypertension. Trace elements Cu and Zn were protective factors for hypertension. Supplemental of Cu and Zn would be helpful to prevention and treatment of hypertension.5. In addition, high BMI, high level of serum Fe and K, drinking behavior were risk factors for hyperlipidemia, while drinking tea was protective factor for hyperlipidemia.6. Moreover, high age, high level of serum K and high LDL-C were risk factors for coronary heart disease.7. Only element Cu showed correlation between level of serum element and the elements intake in dietary nutrition table. |
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