title: [Meta analysis on the relationship between subclinical hypothyroidism and the levels of systolic blood pressure].
abstract: OBJECTIVE
  To investigate the association between subclinical hypothyroidism and levels of systolic blood pressure (SBP), so as to provide evidence for the development of prevention strategy and understanding the etiology of hypertension.
  
  
  METHODS
  The articles on the association of subclinical hypothyroidism and systolic blood pressure levels were retrieved by searching international and national databases from 1999 to 2010. The relationship between subclinical hypothyroidism and systolic blood pressure levels was assessed by meta analysis with Stata 11 software. The weighted mean difference (WMD) and 95% confidence interval (CI) were calculated, and the publication bias was assessed by Begg's test and Egger's test.
  
  
  RESULTS
  (1) There was significant difference in SBP levels between patients with subclinical hypothyroidism and normal subjects (WMD=2.04 mm Hg, 95%CI: 0.64 to 3.45, P<0.05). (2) Subgroup analysis indicated that there was significant difference seen in thyroid stimulating hormone (TSH) mean difference values <7 mU/L group (WMD=2.33 mm Hg, 95%CI: 0.60 to 4.06, P<0.05) but not in the group that TSH mean difference values were >7 mU/L. There was significant difference seen in the Asian group (WMD=2.62 mm Hg, 95%CI: 1.69 to 3.55, P<0.05) in the community group (WMD=2.77 mm Hg, 95%CI: 1.61 to 3.93, P<0.05) but not in the European group and or in the hospital group. There was significant difference in the cross-sectional group (WMD=2.77 mm Hg, 95%CI: 1.61 to 3.93, P<0.05), but not in the case-control group. (3) Results from both Begg's test and Egger's test did not show significant difference, indicating that there was no publication bias existed.
  
  
  CONCLUSIONS
  Subclinical hypothyroidism was associated with the elevated systolic blood pressure. In terms of the role of subclinical hypothyroidism that might serve as one of the potential risk factor for the elevated systolic blood pressure. Well designed and large sample-sized prospective studies were necessary to confirm the association between subclinical hypothyroidism and systolic blood pressure. Random controlled trials were also needed to study whether the treatment could lower the risk. Active treatment for subclinical hypothyroidism might be useful for prevention and treatment of hypertension.
authors.affiliation: Department of Clinical Epidemiology, the First Affiliated Hospital, China Medical University, Shenyang 110001, China.
authors.forename: Yun-fei
authors.initials: YF
authors.lastname: Cai
authors.forename: Jing-pu
authors.initials: JP
authors.lastname: Shi
mesh_terms: D001794:Blood Pressure; D016022:Case-Control Studies; D003430:Cross-Sectional Studies; D006801:Humans; D007037:Hypothyroidism / Q000503:physiopathology*; D012307:Risk Factors; D013599:Systole