The Geographical Distribution Of Cystatin C And Homocysteine Reference Value Of Chinese Healthy Adult

As the major excretory organ,kidney plays a significant role in maintaining the stable internal envirornment.Chronic kidney diseases(CKD)has become a global public health problem,while the functional lesion of glomerular filtration is the one of the major causes.The Cystatin C(Cys-C)and Homocysteine(HCY)have been found to be the sensitive serum marker of evaluating glomerular filtration rate(GFR),which is positive to clinical diagnosis and treatment of CKD.The research concerning the impact factors of Cys-C and HCY reference value now are concentrated in physiological aspects,but there is no report about geographical factors in this field.In this,this study discussed the relationship between Cys-C,HCY reference value of Chinse healthy adult and geographical environment from the prospective of geography,which offered the reference material for establishing the standards of Cys-C,HCY reference values of healthy adult in different region according to local condition,and exploring the influence mechanism of geographical factors on Cys-C,HCY reference value of Chinese healthy adult.A total of 38596 Cys-C measured values of healthy adults from Chinese 252 cities and 36 081 HCYmeasured values of healthy adults from Chinese 218 cities was collected;9 geographical factors,including longitude(X1),latitude(X2),altitude(X3),annual sunshine duration(X4),annual mean temperature(X5),annual precipitation(X6),annual mean wind speed(X7),topsoil organic content(X8),topsoil pH(X9),were selected for analysis.The spatial autocorrelation analysis was used to determine if there was feasibility to conduct spatial analysis;the correlation analysis was utilized to detect which geographical factors were correlated significantly with Cys-C,HCY reference value;the geodetector was used to explore the interpretive degree of each correlated geographical factors to spatial distribution of reference value;the appropriate methods was selected after multicollinearity test to respectively build predictive model,the combined predictive model was also built,then the optimal predictive model was selected by comparing prediction accuracy of each model;the optimal predictive model was used to predict reference values of Chinese 2322 cities,then the suitable interpolation method was selected for constructing spatial distribution map.From the results of correlation analysis,X2,X3,X4,Xs and X6 were significantly correlated with Cys-C reference value of Chinese healthy adults;X1,X3,X6 and X7 were significantly correlated with HCY reference value of Chinese healthy adults.The geodetector suggested that the leading impact factor for spatial distribution of Cys-C and HCY reference value of Chinese healthy adult was altitude.After multicollinearity test,three methods,including principal component analysis(PCA),support vector machine(SVM)and RBF artificial neural network(RBFANN),were used to build predictive models,the optimal predictive model of two medical indexes reference values were combined predictive model.The spatial distribution map showed that Cys-C and HCY reference value of Chinese healthy adults were high in the west and low in the east,they both were negatively associated with altitude.The results of a series of analysis and demonstration indicated that geographical environment was connected closely to Cys-C and HCY reference value of Chinese healthy adults,the formed had a significant impact on the latter's spatial distribution.Combined with Kidney Physiology and Hemorheology,blood viscosity could be changed by various way in different geographical condition,which lead to the spatial differences of Cys-C and HCY reference value.This study explored the relationship between Cys-C,HCY reference value of Chinese healthy adult and geographical factors,which will be beneficial to improve accuracy of clinical diagnosis and provide reference for establishing standards of Cys-C and HCY reference value.The impacts of geographical environment on human health should be put into standard establishment of medical reference value,and the influence mechanism of geographical factors on medical reference value needs to be further discussion.