title: Genetically predicted testosterone and systemic inflammation in men: a separate-sample Mendelian randomization analysis in older Chinese men.
abstract: OBJECTIVE
  Observationally, testosterone is negatively associated with systemic inflammation, but this association is open to both residual confounding and reverse causality. Large-scale randomized controlled trials (RCTs), assessing exogenous effects, are presently unavailable. We examined the association of endogenous testosterone with well-established systemic inflammatory markers (white blood cell, granulocyte, lymphocyte and high-sensitivity C-reactive protein (hsCRP)) using a separate-sample Mendelian randomization analysis to minimize reverse causality.
  
  
  METHODS
  A genetic prediction rule for serum testosterone was developed in 289 young Chinese men with mean age of 21.0, using selected testosterone-related SNPs (rs10046, rs1008805 and rs1256031). Multivariable linear regression was used to examine the association of genetically predicted serum testosterone with inflammatory markers among 4,212 older Chinese men from the Guangzhou Biobank Cohort Study.
  
  
  RESULTS
  Genetically predicted testosterone was unrelated to white blood cell count (-0.01 109/L per nmol/L testosterone, 95% confidence interval (CI) -0.05 to 0.04), granulocyte count (-0.02 109/L, 95% CI -0.06 to 0.02), lymphocyte count (0.005 109/L, 95% CI -0.01 to 0.02) and hsCRP (-0.05 mg/L, 95% CI -0.15 to 0.06).
  
  
  CONCLUSIONS
  Our findings did not corroborate any anti-inflammatory effects of testosterone or corresponding potentially protective effects of testosterone on chronic diseases resulting from reduced low-grade systemic inflammation.
authors.affiliation: School of Public Health, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong Special Administrative Region, Hong Kong, China.
authors.forename: Jie
authors.initials: J
authors.lastname: Zhao
authors.affiliation: Guangzhou Number 12 Hospital, Guangzhou, China.
authors.forename: Chaoqiang
authors.initials: C
authors.lastname: Jiang
authors.affiliation: School of Public Health, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong Special Administrative Region, Hong Kong, China.
authors.forename: Tai Hing
authors.initials: TH
authors.lastname: Lam
authors.affiliation: Guangzhou Number 12 Hospital, Guangzhou, China.
authors.forename: Bin
authors.initials: B
authors.lastname: Liu
authors.affiliation: Department of Public Health and Epidemiology, University of Birmingham, Birmingham, United Kingdom.
authors.forename: Kar Keung
authors.initials: KK
authors.lastname: Cheng
authors.affiliation: School of Public Health, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong Special Administrative Region, Hong Kong, China.
authors.forename: Lin
authors.initials: L
authors.lastname: Xu
authors.affiliation: School of Public Health, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong Special Administrative Region, Hong Kong, China.
authors.forename: Shiu Lun Au
authors.initials: SL
authors.lastname: Yeung
authors.affiliation: Guangzhou Number 12 Hospital, Guangzhou, China.
authors.forename: Weisen
authors.initials: W
authors.lastname: Zhang
authors.affiliation: School of Public Health, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong Special Administrative Region, Hong Kong, China.
authors.forename: Gabriel M
authors.initials: GM
authors.lastname: Leung
authors.affiliation: School of Public Health, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong Special Administrative Region, Hong Kong, China; School of Urban Public Health, Hunter College, CUNY School of Public Health, New York, New York, United States of America.
authors.forename: C Mary
authors.initials: CM
authors.lastname: Schooling
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D002681:China; D006801:Humans; D007249:Inflammation / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D020641:Polymorphism, Single Nucleotide; D013739:Testosterone / Q000032:analysis*
chemical_list: D013739:Testosterone