The Relationship Between Dyslipidemia And Levels Of Heavy Metals In Children Aged 6-9 In A District Of Shenzhen

Background and aimsIn recent years,the prevalence of dyslipidemia in Chinese children has been on the rise.Previous studies have shown that genetics and unhealthy lifestyle are important risk factors for dyslipidemia.In addition,it has been reported that environmental pollution,especially heavy metal exposure,is closely related to it.However,such studies in children are few,so do those about the association between combined exposure to multiple heavy metals and dyslipidemia.This study aims to analyze the relationship between the levels of nine heavy metals and the risk of dyslipidemia in children by screening dyslipidemia and testing the levels of these heavy metals in serum of children aged 6 to 9 years in Shenzhen,to provide evidence for prevention and treatment of dyslipidemia in children.Subjects and methodsCluster sampling was used to select all first-grade children from nineteen primary schools in Shenzhen as our research objects.Blood samples were collected to screen dyslipidemia,which measures levels of total cholesterol(TC),triglyceride cholesterol(triglyceride),Low-density lipoprotein cholesterol(LDL-C)and high-density lipoprotein cholesterol(HDL-C),respectively.The information of children’s lifestyle taken via questionnaire survey was used to analyze the influence factors of dyslipidemia.On this basis,the children with dyslipidemia were selected as the experimental group,and healthy ones as the control group by 1:1 matching according to age±0.5 years old and gender.The levels of lead(Pb),cadmium(Cd),chromium(Cr),manganese(Mn),aluminum(Al),vanadium(V),nickel(Ni),arsenic(As)and strontium(Sr)in theserum of the two groups were detected by inductively coupled plasma(ICP-MS).Median and interquartile range were used to describe non-normally disturbed quantitative data.Chi-square test or nonparametric rank-sum test was used for comparison among groups.Conditional logistic regression was used to analyze the relationship between serum heavy metals and the risk of dyslipidemia.Spearman correlation was used to analyze the correlation between heavy metals.Principal component analysis was used to analyze the relationship between combined exposure to multiple heavy metals and dyslipidemia.Results1.A total of 4721 children were investigated in this survey,and 4513 children were included in the final analysis.Among them,the mean age was 7.1±0.3 years old and 56.3%were boys(2414/4513).The total prevalence of dyslipidemia was 14.7%(13.6% in boys and16.1% in girls).The prevalence of high TC,high TG,low HDL-C and high LDL-C were 6.5%,1.6%,6.6% and 4.0%,respectively.The prevalence of dyslipidemia varied in gender,family history of dyslipidemia,overweight or obesity(P<0.05).2.Theserum levels of Pb,Cd,Mn,Al,V,Ni and Sr in the experimental group(n=663)were significantly higher than those in the control group(n=663)(133.08μg/L vs 84.19μg/L,0.45μg/L vs 0.29μg/L,11.45μg/L vs 10.50μg/L,466.21μg/L vs 417.97μg/L,1.33μg/L vs1.22μg/L,26.32μg/L vs 17.03μg/L,54.51μg/L vs 45.74μg/L,P<0.05).3.After adjusting for covariates,there was atendency toward a dose-response relationship between the increasing quantities of the serum levels of Pb,Cd,Mn,V,Ni and Sr,the risk of dyslipidemia(P for trend <0.05).Compared with thefirst quintile group of serum levels of Pb,Cd,Mn,V,Ni,and Sr,theodds ratiosof the risk of dyslipidemia of children in the fourth quintile group were at were 3.37(95%CI: 2.40-4.73),6.58(95%CI: 4.55-9.50),1.92(95%CI: 2.40-9.50),3.22(95%CI: 2.29-4.55),1.59(95%CI: 1.14-2.22)and 2.62(95%CI: 1.87-3.67),respectively.4.Correlation analysis showed that there was a strong correlation amongall metal elements in serum(P< 0.05),and the correlation coefficients of Cd and V,Pb and Cr,Cd and Al,V and Al,Pb and Cr,Pb and Ni,Cr and Ni werehigher(all r>0.4).5.Principal component analysis showed that principal component 1(representing Pb,Cr,Mn,Ni,and Sr)was associated with increased risk of dyslipidemia,hypercholesterolemia,and hypertriglyceridemia in children(all P< 0.05).Principal component 2(representing Cd,Al,V,and As)was associated with an increased risk of dyslipidemia(P< 0.05).Conclusions1.The prevalence of dyslipidemia was 14.7% in children aged 6 to 9 years in Shenzhen with mostly low HDL-C and high TC,and higher in girls than boys.2.There were strong correlations among the nine heavy metals in children’s serum.3.The exposure levels of various heavy metals in children’s serum may be associated with the increased risk of dyslipidemia,especially Cd and Pb exposures.4..The combined effects of Pb,Cr,Mn,Sr,Ni,Cd,Al,V,As and the risk of dyslipidemia are different from the single effects of heavy metals,and there may be synergistic or antagonistic effects.