title: Alteration of lipid profile in subclinical hypothyroidism: a meta-analysis.
abstract: BACKGROUND
  Previous studies yielded controversial results about the alteration of lipid profiles in patients with subclinical hypothyroidism. We performed a meta-analysis to investigate the association between subclinical hypothyroidism and lipid profiles.
  
  
  METHODS
  We searched PubMed, Cochrane Library, and China National Knowledge Infrastructure articles published January 1990 through January 2014. Dissertation databases (PQDT and CDMD) were searched for additional unpublished articles. We included articles reporting the relationship between subclinical hypothyroidism and at least 1 parameter of lipid profiles, and calculated the overall weighted mean difference (WMD) with a random effects model. Meta-regression was used to explore the source of heterogeneity among studies, and the Egger test, Begg test, and the trim and fill method were used to assess potential publication bias.
  
  
  RESULTS
  Sixteen observational studies were included in our analysis. Meta-analysis suggested that the serum total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), and total triglyceride levels were significantly increased in patients with subclinical hypothyroidism compared with euthyroidism individuals; the WMD were 12.17 mg/dl, 7.01 mg/dl, and 13.19 mg/dl, respectively (P<0.001 for all). No significant difference was observed for serum high-density lipoprotein cholesterol (HDL-C). Match strategy was the main source of heterogeneity among studies in TC and LDL-C analysis. Potential publication bias was found in TC and LDL-C analysis by the Egger test or Begg test and was not confirmed by the trim and fill method.
  
  
  CONCLUSIONS
  Subclinical hypothyroidism may correlate with altered lipid profile. Previous studies had limitations in the control of potential confounding factors and further studies should consider those factors.
authors.affiliation: Molecular Biology Lab, Shenzhen Center for Chronic Disease Control, Shenzhen, China (mainland).
authors.forename: Xiao-Li
authors.initials: XL
authors.lastname: Liu
authors.affiliation: Molecular Biology lab, Shenzhen Center for Chronic Disease Control, Shenzhen, China (mainland).
authors.forename: Shan
authors.initials: S
authors.lastname: He
authors.affiliation: Department of Social Health, Shenzhen Luohu People's Hospital, Shenzhen, China (mainland).
authors.forename: Shao-Fang
authors.initials: SF
authors.lastname: Zhang
authors.affiliation: Physicochemical Lab, Shenzhen Center for Chronic Disease Control, Shenzhen, China (mainland).
authors.forename: Jun
authors.initials: J
authors.lastname: Wang
authors.affiliation: Department of Nutrition and Food Hygiene, Huazhong University of Science and Technology, Wuhan, China (mainland).
authors.forename: Xiu-Fa
authors.initials: XF
authors.lastname: Sun
authors.affiliation: Molecular biology lab, Shenzhen Center for Chronic Disease Control, Shenzhen, China (mainland).
authors.forename: Chun-Mei
authors.initials: CM
authors.lastname: Gong
authors.affiliation: Molecular Biology Lab, Shenzhen Center for Chronic Disease Control, Shenzhen, China (mainland).
authors.forename: Shi-Jie
authors.initials: SJ
authors.lastname: Zheng
authors.affiliation: Molecular Biology Lab, Shenzhen Center for Chronic Disease Control, Shenzhen, China (mainland).
authors.forename: Ji-Chang
authors.initials: JC
authors.lastname: Zhou
authors.affiliation: Department of Health Control, Shenzhen Center for Chronic Disease Control, Shenzhen, China (mainland).
authors.forename: Jian
authors.initials: J
authors.lastname: Xu
mesh_terms: D002784:Cholesterol / Q000097:blood; D008078:Cholesterol, LDL / Q000097:blood; D006801:Humans; D007037:Hypothyroidism / Q000378:metabolism*; D008055:Lipids / Q000097:blood*; D064887:Observational Studies as Topic; D012044:Regression Analysis; D014280:Triglycerides / Q000097:blood
chemical_list: D008078:Cholesterol, LDL; D008055:Lipids; D014280:Triglycerides; D002784:Cholesterol