The Relationship of Latent Toxoplasmosis and Cigarette Smoking: Seroprevalence, Risk Factor, and Case-Control Study in Fars Province, Southern Iran

Toxoplasmosis is a parasitic disease with worldwide prevalence. Despite the relatively similar effects of toxoplasmosis and smoking on alteration in neurotransmitters, especially dopamine, little is known about the relation of Toxoplasma gondii infection and addiction to cigarette smoking. Therefore, the main objective of this study was to assess the relationship between latent toxoplasmosis and smoking. Through a case-control study, 216 regular cigarette smokers and 324 nonsmoker age- and gender-matched subjects were evaluated for anti-T.gondii IgG antibodies with enzyme-linked immunosorbent assay (ELISA). During the sampling, a structured questionnaire was used to obtain the demographic information of participants and the risk factors of acquired Toxoplasma. The median ages of case and control groups were 51.04 ± 18.1 (22–97 years) and 51.03 ± 16.5 (21–89 years), respectively (p = 0.99). Anti-T.gondii IgG antibodies were detected in 44 (20.37%) cases and in 135 (41.67%) controls. There was a statistically significant difference for the positivity rate between the smokers and the control group (OR = 0.35; 95%CI: 0.19–0.65; and p = 0.001). The overall prevalence was 33.14%. This study indicated the inverse association between seropositivity to Toxoplasma infection and cigarette smoking. This relationship could be due to the changes that latent toxoplasmosis has on the neurotransmitters, especially dopamine, which needs more research.