title: Is chronic toxoplasmosis a risk factor for diabetes mellitus? A systematic review and meta-analysis of case-control studies.
abstract: BACKGROUND
  The global protozoan parasite, Toxoplasma gondii, infects many warm-blooded animals and humans by employing different transmission routes. There have been some recent studies on the probable relevance of infectious agents and diabetes. Therefore, we conducted a systematic review and meta-analysis to identify the possible association between chronic toxoplasmosis and diabetes mellitus.
  
  
  METHODS
  This study was conducted following the general methodology recommended for systematic reviews and meta-analysis. Nine English literature databases (Google scholar, PubMed, Scopus, Web of science, Science Direct, Ovid, ProQuest, IngentaConnect, and Wiley Online Library) were searched, up to January 2016. Random effects model was used to determine odds ratios and their 95% confidence intervals.
  
  
  RESULTS
  Our review resulted in a total of seven publications meeting the inclusion criteria. Because of significant heterogeneity, we estimated a common OR by a random effects model at 1.10 (95% CI=0.13-9.57) with p=0.929 and 2.39 (95% CI=1.20-4.75) with p=0.013 for type 1 and type 2 diabetes mellitus, respectively.
  
  
  CONCLUSIONS
  Despite the limitations such as low number of studies, this meta-analysis suggests chronic toxoplasmosis as a possible risk factor for type 2 DM. However, based on random effects model no statistically significant association was observed between T. gondii and type 1 DM. It is highly recommended for researchers to carry out more accurate studies aiming to better understand this association.
authors: Tarbiat Modares University, Faculty of Medical Sciences, Department of Parasitology, Tehran, Iran.
authors: Hamidreza
authors: H
authors: Majidiani
authors: Kurdistan University of Medical Sciences, Social Determinants of Health Research Center, Sanandaj, Iran.
authors: Sahar
authors: S
authors: Dalvand
authors: Mazandaran University of Medical Sciences, Toxoplasmosis Research Center, Sari, Iran.
authors: Ahmad
authors: A
authors: Daryani
authors: University of Guadalajara, Health Sciences University Center, Department of Physiology, Researcher of Neurophysiology Laboratory, Guadalajara, Mexico.
authors: Ma de la Luz
authors: ML
authors: Galvan-Ramirez
authors: Ahvaz Jundishapur University of Medical Sciences, Faculty of Medicine, Department of Medical Parasitology, Ahvaz, Iran. Electronic address: masoud_foroutan_rad@yahoo.com.
authors: Masoud
authors: M
authors: Foroutan-Rad
mesh_terms: D016022:Case-Control Studies; D002908:Chronic Disease; D003920:Diabetes Mellitus / Q000469:parasitology*; D006801:Humans; D012307:Risk Factors; D014123:Toxoplasmosis / Q000150:complications*
keywords: Diabetes mellitus; Meta-analysis; Systematic review; Toxoplasma gondii