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Increased risk of traffic accidents in subjects with latent toxoplasmosis: a retrospective case-control study.

Flegr J, Havlícek J, Kodym P, Malý M, Smahel Z - BMC Infect. Dis. (2002)

Bottom Line: It is not know, however, whether the changes observed in laboratory influence the performance of subjects in real-life situations.Relative risk of traffic accidents decreases with the duration of infection.These results suggest that 'asymptomatic' acquired toxoplasmosis might in fact represent a serious and highly underestimated public health as well as economic problem.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Parasitology, Faculty of Science, Charles University, Prague, Czech Republic. flegr@cesnet.cz

ABSTRACT

Background: The parasite Toxoplasma gondii infects 30-60% of humans worldwide. Latent toxoplasmosis, i.e., the life-long presence of Toxoplasma cysts in neural and muscular tissues, leads to prolongation of reaction times in infected subjects. It is not know, however, whether the changes observed in laboratory influence the performance of subjects in real-life situations.

Methods: The seroprevalence of latent toxoplasmosis in subjects involved in traffic accidents (N=146) and in the general population living in the same area (N=446) was compared by a Mantel-Haenszel test for age-stratified data. Correlation between relative risk of traffic accident and a level of anti-Toxoplasma antibody titre was evaluated with the Cochran-Armitage test for trend.

Results: A higher seroprevalence was found in the traffic accident set than in the general population (Chi2MH=21.45, p<0.0001). The value of the odds ratio (OR) suggests that subjects with latent toxoplasmosis had a 2.65 (C.I.95= 1.764.01) times higher risk of an accident than the toxoplasmosis-negative subjects. The OR significantly increased with level of anti-Toxoplasma antibody titre (p<0.0001), being low (OR=1.86, C.I.95=1.14-3.03) for the 99 subjects with low antibody titres (8 and 16), higher (OR=4.78, C.I.95=2.39-9.59) for the 37 subjects with moderate titres (32 and 64), and very high (OR=16.03, C.I.95=1.89-135.66) for the 6 subjects with titres higher than 64.

Conclusion: The subjects with latent toxoplasmosis have significantly increased risk of traffic accidents than the noninfected subjects. Relative risk of traffic accidents decreases with the duration of infection. These results suggest that 'asymptomatic' acquired toxoplasmosis might in fact represent a serious and highly underestimated public health as well as economic problem.

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Seroprevalence of latent toxoplasmosis The figure shows difference in seroprevalence of latent toxoplasmosis (%) between the representative sample of general Prague residents (controls) and the sample of Prague residents involved in traffic accidents between 1997–2000 (victims). For numbers of subjects in particular categories, see Table 1.
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Figure 1: Seroprevalence of latent toxoplasmosis The figure shows difference in seroprevalence of latent toxoplasmosis (%) between the representative sample of general Prague residents (controls) and the sample of Prague residents involved in traffic accidents between 1997–2000 (victims). For numbers of subjects in particular categories, see Table 1.

Mentions: The seroprevalence of latent toxoplasmosis in subjects involved in traffic accidents and in the general population was compared by a Mantel-Haenszel test for age-stratified data (Table 1, Fig. 1). The result suggests a significantly higher seroprevalence in the traffic accident set (Chi2MH = 21.45, p < 0.0001). The value of the odds ratio (OR) suggests that subjects with latent toxoplasmosis had a 2.65 (C.I.95= 1.76–4.01) times higher risk of a traffic accident than the toxoplasmosis-negative subjects. The ORs varied between particular age strata; however, the test of homogeneity of odds ratios shows that these differences are not significant (Zelen statistics = 0.0076, p = 0.88). Analyses of the traffic accident sample found no significant differences in ORs between drivers and pedestrians or between men and women. To check the robustness of our results, we repeated all analyses with six different age strata (15–19, 20–29, 30–39, 40–49, 50–59, and 60–70 years). The results were very similar to those reported in Table 1. However, due to the low number of observations in some strata, the relative risks in particular age strata fluctuated. (The total OR = 2.48, C.I.95= 1.64–3.77; age 15–19, OR = 1.87, C.I.95 = 0.36–9.73; age 20–29, OR = 2.79, C.I.95 = 1.35–5.78; age 30–39, OR = 1.06, C.I.95 = 0.28–3.96; age 40–49, OR = 4.04, C.I.95 = 1.32–12.39; age 50–59, OR = 2.12, C.I.95 = 0.83–5.43; and age 60–70, OR = 3.16, C.I.95 = 1.05–9.52.) Again, there was no significant difference in age of the accident and control groups within these age strata (p = 0.25, Pitman's exact test).


Increased risk of traffic accidents in subjects with latent toxoplasmosis: a retrospective case-control study.

Flegr J, Havlícek J, Kodym P, Malý M, Smahel Z - BMC Infect. Dis. (2002)

Seroprevalence of latent toxoplasmosis The figure shows difference in seroprevalence of latent toxoplasmosis (%) between the representative sample of general Prague residents (controls) and the sample of Prague residents involved in traffic accidents between 1997–2000 (victims). For numbers of subjects in particular categories, see Table 1.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC117239&req=5

Figure 1: Seroprevalence of latent toxoplasmosis The figure shows difference in seroprevalence of latent toxoplasmosis (%) between the representative sample of general Prague residents (controls) and the sample of Prague residents involved in traffic accidents between 1997–2000 (victims). For numbers of subjects in particular categories, see Table 1.
Mentions: The seroprevalence of latent toxoplasmosis in subjects involved in traffic accidents and in the general population was compared by a Mantel-Haenszel test for age-stratified data (Table 1, Fig. 1). The result suggests a significantly higher seroprevalence in the traffic accident set (Chi2MH = 21.45, p < 0.0001). The value of the odds ratio (OR) suggests that subjects with latent toxoplasmosis had a 2.65 (C.I.95= 1.76–4.01) times higher risk of a traffic accident than the toxoplasmosis-negative subjects. The ORs varied between particular age strata; however, the test of homogeneity of odds ratios shows that these differences are not significant (Zelen statistics = 0.0076, p = 0.88). Analyses of the traffic accident sample found no significant differences in ORs between drivers and pedestrians or between men and women. To check the robustness of our results, we repeated all analyses with six different age strata (15–19, 20–29, 30–39, 40–49, 50–59, and 60–70 years). The results were very similar to those reported in Table 1. However, due to the low number of observations in some strata, the relative risks in particular age strata fluctuated. (The total OR = 2.48, C.I.95= 1.64–3.77; age 15–19, OR = 1.87, C.I.95 = 0.36–9.73; age 20–29, OR = 2.79, C.I.95 = 1.35–5.78; age 30–39, OR = 1.06, C.I.95 = 0.28–3.96; age 40–49, OR = 4.04, C.I.95 = 1.32–12.39; age 50–59, OR = 2.12, C.I.95 = 0.83–5.43; and age 60–70, OR = 3.16, C.I.95 = 1.05–9.52.) Again, there was no significant difference in age of the accident and control groups within these age strata (p = 0.25, Pitman's exact test).

Bottom Line: It is not know, however, whether the changes observed in laboratory influence the performance of subjects in real-life situations.Relative risk of traffic accidents decreases with the duration of infection.These results suggest that 'asymptomatic' acquired toxoplasmosis might in fact represent a serious and highly underestimated public health as well as economic problem.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Parasitology, Faculty of Science, Charles University, Prague, Czech Republic. flegr@cesnet.cz

ABSTRACT

Background: The parasite Toxoplasma gondii infects 30-60% of humans worldwide. Latent toxoplasmosis, i.e., the life-long presence of Toxoplasma cysts in neural and muscular tissues, leads to prolongation of reaction times in infected subjects. It is not know, however, whether the changes observed in laboratory influence the performance of subjects in real-life situations.

Methods: The seroprevalence of latent toxoplasmosis in subjects involved in traffic accidents (N=146) and in the general population living in the same area (N=446) was compared by a Mantel-Haenszel test for age-stratified data. Correlation between relative risk of traffic accident and a level of anti-Toxoplasma antibody titre was evaluated with the Cochran-Armitage test for trend.

Results: A higher seroprevalence was found in the traffic accident set than in the general population (Chi2MH=21.45, p<0.0001). The value of the odds ratio (OR) suggests that subjects with latent toxoplasmosis had a 2.65 (C.I.95= 1.764.01) times higher risk of an accident than the toxoplasmosis-negative subjects. The OR significantly increased with level of anti-Toxoplasma antibody titre (p<0.0001), being low (OR=1.86, C.I.95=1.14-3.03) for the 99 subjects with low antibody titres (8 and 16), higher (OR=4.78, C.I.95=2.39-9.59) for the 37 subjects with moderate titres (32 and 64), and very high (OR=16.03, C.I.95=1.89-135.66) for the 6 subjects with titres higher than 64.

Conclusion: The subjects with latent toxoplasmosis have significantly increased risk of traffic accidents than the noninfected subjects. Relative risk of traffic accidents decreases with the duration of infection. These results suggest that 'asymptomatic' acquired toxoplasmosis might in fact represent a serious and highly underestimated public health as well as economic problem.

Show MeSH
Related in: MedlinePlus