The Relationship Between Environmental Exposure To Metals And Serum Reproductive Hormone Levels In Men

Part I Relationship between urinary metal concentrations and serum reproductive hormone levels in menObjective: To examine the association of environmental expsoure to metals with serum reproductive hormone levels,using urinary metals as internal biomarkers.Methods: A total of 1052 men attending a reproductive center in Wuhan between March 2013 and June 2013 were chosen to complete the questionnaires.The urinary concentrations of aluminum(AI),chromium(Cr),manganese(Mn),iron(Fe),cobalt(Co),nickel(Ni),copper(Cu),zinc(Zn),arsenic(As),selenium(Se),molybdenum(Mo),cadmium(Cd),antimony(Sb),tin(Sn),tungsten(W),thallium(TI),lead(Pb)and uranium(U)were measured.Multivariable linear regression models were utilized to assess the correlation between the concentrations of urinary metals and serum estradio(E),follicle-stimulating hormone(FSH),luteinizing hormone(LH),sex hormone-binding globulin(SHBG),testosterone(T),free testosterone(FT)and the ratio of T to LH(T/LH ratio)in 511 men.Results: Multivariate linear regression analysis showed that serum T level in the group of the highest urinary Sn concentration(>P75)was significantly decreased(?=-16%,95% CI:-27%,-4.7%)compared with the group of the lowest urinary Sn concentration(<P25).Meanwhile,T/LH ratio in the groups of the highest urinary Sn,Ni,Zn and Mo concentrations(>P75)were significantly decreased(?=-25%,95% CI:-42,-9.4%;?=-20%,95% CI:-38,-4.2%;?=-18%,95% CI:-35,-2.6%;?=-22%,95% CI:-39,-6.5%)compared with the groups of the lowest urinary Sn,Ni,Zn and Mo concentrations(<P25).Conclusion: In this part our results suggested that elevated urinary Sn,Ni,Zn and Mo concentrations may be associated with decreased serum T level or T/LH ratio in men.Part II Relationship between seminal plasma metal concentrations and serum reproductive hormone levels in menObjective: To further examine the association of environmental expsoure to metals with serum reproductive hormone levels,using seminal plasma metals as internal biomarkers of male reproductive system.Methods: A total of 746 men with sufficient semen volumes were chosen from the first part to measure 17 metals in seminal plasma.Multivariable linear regression models were utilized to assess the correlation between the concentrations of seminal plasma metals and serum reproductive hormone levels in 378 men.Results: Multivariable linear regression models showed that serum FSH levels in the groups of the highest concentrations of Co,Se and TI in seminal plasma(>P75)were significantly increased(?=18.50,95%CI: 2.00,36.00;?=17.40,95%CI: 0.80,35.00;?=18.50,95%CI: 3.40,37.70)compared with the groups of the lowest these metals concentrations in seminal plasma(<P25).The serum LH level in the group of the highest concentration of Mo in seminal plasma(>P75)was significantly increased(?=12.50,95%CI: 0.10,27.00)compared with the group of the lowest Mo concentration in seminal plasma(<P25).The serum LH level in the group of the highest concentration of Cr in seminal plasma(>P75)was decreased(?=-0.90,95%CI:-22.00,1.50,suggestive negative association)compared with the group of the lowest Cr concentration in seminal plasma(<P50).The serum SHBG level in the group of the highest concentrations of Cd,and Co in seminal plasma(>P75)were significantly increased(?=18.00,95% CI: 5.10,36.00;?=16.20,95% CI: 4.00,31.00)compared with the group of the lowest these metals in seminal plasma(<P25).The serum SHBG level in the group of the highest concentration of Zn and Mo in seminal plasma(>P75)was increased(?=7.80 L,95% CI:-4.00,21.00;?=13.00,95% CI:0.40,27.00,suggestive positive association)compared with the group of the lowest Zn and Mo concentration in seminal plasma(<P25).The serum T level in the group of the highest concentration of Sn in seminal plasma(>P80)was decreased(?=-7.30,95% CI:-17.40,2.00,suggestive negative association)compared with the group of the lowest Sn concentration in seminal plasma(<P60).Conclusion: In this part our results suggested that elevated seminal plasma Cr,Co,Zn,Se,Mo,Sn,TI and Cd concentrations may be associated with the alternations of serum reproductive hormone levels in men.