title: Hepatitis C virus infection and risk of thyroid cancer: A systematic review and meta-analysis.
abstract: OBJECTIVE
  Several epidemiological studies investigated the relationship between hepatitis C virus (HCV) infection and risk of thyroid cancer, but the results were not consistent. A systematic review and meta-analysis was conducted to assess the impact of HCV infection on thyroid cancer risk.
  
  
  METHODS
  The literature was searched up to March 15, 2016 for case-control or cohort studies on the association between HCV infection and thyroid cancer risk. The summary relative risks (RR) and 95% confidence intervals (CI) were calculated.
  
  
  RESULTS
  Five studies (two case-control studies and three cohort studies) were included in the meta-analysis, with a total of 751,551 participants and 367 cases of thyroid cancer. Meta-analysis of those 5 studies found that there was no statistically significant association between HCV infection and thyroid cancer risk (summary RR=2.09, 95%CI 0.78-5.64, p=0.145; I2=81.2%). However, HCV infection was significantly associated with increased risk of thyroid cancer (summary RR=2.86, 95%CI 1.63-5.03, p=0.003; I2=24.9%) after adjusting the heterogeneity.
  
  
  CONCLUSIONS
  There is a possible association between HCV infection and increased risk of thyroid cancer, and more cohort studies are needed to validate the possible association.
authors.affiliation: Department of Endocrinology, Chengyang People's Hospital of Qingdao City, Qingdao 266003, China.
authors.forename: Peng
authors.initials: P
authors.lastname: Wang
authors.affiliation: Department of Endocrinology, People's Hospital of Ri Zhao, Ri Zhao 276800, China.
authors.forename: Zhaohai
authors.initials: Z
authors.lastname: Jing
authors.affiliation: Department of Endocrinology, Chengyang People's Hospital of Qingdao City, Qingdao 266003, China.
authors.forename: Changjiang
authors.initials: C
authors.lastname: Liu
authors.affiliation: Department of Endocrinology, Chengyang People's Hospital of Qingdao City, Qingdao 266003, China.
authors.forename: Meihua
authors.initials: M
authors.lastname: Xu
authors.affiliation: Department of Endocrinology, Chengyang People's Hospital of Qingdao City, Qingdao 266003, China.
authors.forename: Pei
authors.initials: P
authors.lastname: Wang
authors.affiliation: Department of Endocrinology, Chengyang People's Hospital of Qingdao City, Qingdao 266003, China.
authors.forename: Xiao
authors.initials: X
authors.lastname: Wang
authors.affiliation: Department of Endocrinology, Chengyang People's Hospital of Qingdao City, Qingdao 266003, China.
authors.forename: Yulei
authors.initials: Y
authors.lastname: Yin
authors.affiliation: Department of Endocrinology, Chengyang People's Hospital of Qingdao City, Qingdao 266003, China.
authors.forename: Ying
authors.initials: Y
authors.lastname: Cui
authors.affiliation: Emergency Department, Chengyang People's Hospital of Qingdao City, Qingdao 266003, China.
authors.forename: Dunlin
authors.initials: D
authors.lastname: Ren
authors.affiliation: Department of Endocrinology, Chengyang People's Hospital of Qingdao City, Qingdao 266003, China. Electronic address: qdraoxiaopang@163.com.
authors.forename: Xiaopang
authors.initials: X
authors.lastname: Rao
mesh_terms: D014943:Global Health; D016174:Hepacivirus; D006526:Hepatitis C / Q000150:complications / Q000175:diagnosis / Q000821:virology; D006801:Humans; D015994:Incidence; D012307:Risk Factors; D013964:Thyroid Neoplasms / Q000175:diagnosis / Q000453:epidemiology / Q000209:etiology
keywords: Hepatitic C virus; Meta-analysis; Thyroid cancer