The Association between Toxoplasma gondii Infection and Risk of Parkinson’s Disease: A Systematic Review and Meta-Analysis

Table 2

Characteristics and methodological quality of included studies for analysis of T. gondii infection and risk of PD.

Studies; years of publication; country	Study design	Participants		Number; age (years); male%		Exposure measures	OR (95% CI)	Adjustments	NOS score
		Case	Control	PD	Control
Alvarado-Esquivel et al [28]; 2017; Mexico	Case-control	Patients with PD	Subjects without PD	65; 69.08±11.39; 46.15	195; 68.56±10.08; 46.15	: latent infection, positive serum anti-T. gondii IgG antibodies; : acute infection, positive serum anti-T. gondii IgM antibodies; Non-exposure: no infection, negative serum anti-T. gondii IgG or IgM antibodies	: 0.84 (0.32, 2.18; : 0.33 (0.02, 6.12	Age, gender	8
Fallahi et al [11]; 2017; Iran	Case-control	PD patients	Healthy individuals	115; 75.2±13.1; NA	115; 74.1±14.4; NA		: 0.90 (0.54, 1.51; 3.02 (0.31, 29.80	Age, sex and place of residence	7
Ramezani (a) et al [26]; 2016; Iran	Case-control	Individuals with IPD	Healthy subjects;	41; 76.3±6; 78	69; 62±8; 78.2;		: 2.27 (0.69, 7.5; : 1.06 (0.04, 27.04	Sex, age and socioeconomic status	8
Ramezani (b) et al [26]; 2016; Iran			Patients without PD		40; 64.6±3.5; 77.5;	: latent infection, positive serum anti-T. gondii IgG antibodies; Non-exposure: no infection, negative serum anti-T. gondii IgG or IgM antibodies	: 3.05 (0.76, 12.24
Oskouei et al [29]; 2014; Iran	Case-control	Parkinson’s patients	Healthy subjects	75; 63.7±11.3; 77.3	75; 63.4±11.6; NA		: 0.59 (0.20, 1.60	Age, gender, residency, education, cat keeping, using raw or undercooked meat and egg	7
Celik et al [37]; 2013; Turkey	Case-control	Patients with IPD	Healthy individuals	50; 65.6±10.2; 64	50; 65.6±30.4; 58	: latent infection, positive serum anti-T. gondii IgG antibodies; Non-exposure: no infection, negative serum anti-T. gondii IgG or IgM antibodies	: 0.78 (0.29, 2.08	Age, gender	7
Celik et al [38]; 2010; Turkey	Case-control	Patients with IPD	Healthy individuals	50; 63.39±13.21; 60	45; 62.38±11.55; 64		: 1.33 (0.60, 2.96	Age	5
Miman et al [27]; 2010; Turkey	Case-control	Patients with PD	Healthy individuals	52; 66.01±12.14; 61.54	40; 62.42±5.93; 52.5		: 3.26 (1.31, 8.09	Age, gender, socioeconomic status	6

T. gondii: Toxoplasma gondii; PD: Parkinson’s disease; NOS: Newcastle-Ottawa quality assessment scale; NA: not available; IPD: idiopathic Parkinson’s disease; IgG: immunoglobulin G; IgM: immunoglobulin M.
∗Adjusted value obtained from original reports; ∗∗value calculated according to counts of event and total number of two groups in individual study.
Data were presented as mean ± standard deviation where appropriate.