title: Subclinical hypothyroidism and the risk of metabolic syndrome: A meta-analysis of observational studies.
abstract: BACKGROUND
  Observational studies on the association between subclinical hypothyroidism (SCH) and metabolic syndrome (MetS) have produced inconsistent results. Therefore, we performed a meta-analysis to evaluate the effect of SCH on the risk of MetS.
  
  
  METHODS
  Multiple databases were searched to identify studies on the association between SCH and the risk of MetS, up to February 2015. Relevant information for analysis was extracted. A random-effects model was used to calculate the pooled risk estimates.
  
  
  RESULTS
  9 studies (7 cross-sectional and 2 case-control studies) were included. The pooled odds ratio (OR) for MetS comparing SCH with euthyroid subjects was 1.31 (95%CI: 1.08 to 1.60, p = 0.006, I(2) = 50%). Subgroup analyses by countries revealed a significant association for the studies from Asian (OR = 1.244, 95% CI: 1.030-1.503, I(2) = 25%) other than non-Asian (OR = 1.548, 95% CI: 0.925-2.591, I(2) = 73.5%) countries. A positive association was identified in the IDF subgroup (OR = 1.288, 95% CI: 1.055-1.572, I(2) = 0%), but not in the NCEP-ATP III (OR = 1.351, 95% CI: 0.950-1.923, I(2) = 66.4%), Chinese (OR = 1.430, 95% CI: 0.891-2.294) and Japanese (OR = 1.542, 95% CI: 0.594-4.005, I(2) = 78.3%) subgroup. A certain degree of heterogeneity was observed among studies which cannot be explained by study design, diagnostic criteria and location.
  
  
  CONCLUSIONS
  Our results demonstrated that SCH was significantly associated with a higher risk of MetS. Well-designed cohort studies were warranted to confirm our findings.
authors.affiliation: a Department of Endocrinology , Taian city Central Hospital , Taian city , Shandong Province , People's Republic of China.
authors.forename: Libo
authors.initials: L
authors.lastname: Yang
authors.affiliation: a Department of Endocrinology , Taian city Central Hospital , Taian city , Shandong Province , People's Republic of China.
authors.forename: Xiaohong
authors.initials: X
authors.lastname: Lv
authors.affiliation: a Department of Endocrinology , Taian city Central Hospital , Taian city , Shandong Province , People's Republic of China.
authors.forename: Feng
authors.initials: F
authors.lastname: Yue
authors.affiliation: a Department of Endocrinology , Taian city Central Hospital , Taian city , Shandong Province , People's Republic of China.
authors.forename: Dailin
authors.initials: D
authors.lastname: Wei
authors.affiliation: a Department of Endocrinology , Taian city Central Hospital , Taian city , Shandong Province , People's Republic of China.
authors.forename: Wen
authors.initials: W
authors.lastname: Liu
authors.affiliation: a Department of Endocrinology , Taian city Central Hospital , Taian city , Shandong Province , People's Republic of China.
authors.forename: Tie
authors.initials: T
authors.lastname: Zhang
mesh_terms: D015897:Comorbidity; D006801:Humans; D007037:Hypothyroidism / Q000453:epidemiology*; D024821:Metabolic Syndrome / Q000453:epidemiology*; D064887:Observational Studies as Topic
keywords: Subclinical hypothyroidism; meta-analysis; metabolic syndrome