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Published on: August 7, 2017
Toxocariasis and childhood asthma: A case-control study
Priscila Silva Cadore1, Linjie Zhang1, Liliam de Lima Lemos2
1a Postgraduate Program in Health Sciences, Faculty of Medicine , Federal University of Rio Grande , Rio Grande , Brazil.
Insights
This study found no significant link between Toxocara infection and childhood asthma. However, factors like low income, family history of asthma, and cat contact were associated with increased asthma risk.
Area of Science:
- Pediatric Allergy and Immunology
- Infectious Diseases Epidemiology
- Environmental Health
Background:
- Toxocara infection is a common helminthic zoonosis with potential immunomodulatory effects.
- Asthma is a prevalent chronic respiratory disease in children, with multifactorial etiology.
- The potential role of parasitic infections, including Toxocara, in the development or exacerbation of asthma remains an area of investigation.
Purpose of the Study:
- To investigate the association between seropositivity to anti-Toxocara IgG antibodies and the risk of asthma in children.
- To identify other risk factors associated with childhood asthma in the studied population.
Main Methods:
- A case-control study was conducted with 208 children (156 cases with asthma, 52 controls without asthma) in South Brazil.
- Participants were matched by age, and data were collected via interviews and serological testing for anti-Toxocara IgG using ELISA.
- Statistical analysis included calculating odds ratios (OR) with 95% confidence intervals (CI) to assess associations.
Main Results:
- The seroprevalence of anti-Toxocara IgG was 12.8% in children with asthma and 7.7% in controls.
- No statistically significant association was found between anti-Toxocara IgG seropositivity and asthma risk (adjusted OR: 1.89, p=0.33).
- Independent risk factors for asthma included low household income, low paternal education, allergic rhinitis, family history of asthma/rhinitis, and cat contact.
Conclusions:
- This study did not establish a statistically significant link between Toxocara infection and childhood asthma.
- Low socioeconomic status, family history of allergic diseases, and environmental exposures like cat contact are significant factors associated with childhood asthma.
Objective:
The objective of this study is to investigate the association between anti-Toxocara IgG seropositivity and asthma in children.
Methods:
This was a case-control study conducted in a university hospital in south Brazil between May 2012 and June 2013. Were recruited 208 children up to 12 years old of whom 156 had asthma (cases) and 52 did not have asthma (controls), with a case-control ratio of 3:1 matched by age. Children's parents or guardians were interviewed using a structured questionnaire with closed questions. Serology was performed using enzyme-linked immunosorbent assay (ELISA) with excretory-secretory antigen of Toxocara canis (TES).
Results:
The seroprevalence of IgG anti-T. canis antibodies was 12.8% in the cases and 7.7% in the controls. There was no significant association between seropositivity to T. canis and risk of asthma (adjusted odds ratio [OR]: 1.89, 95% CI: 0.52 to 6.89, p = 0.33). Household income < 2 minimum salaries, paternal school years < 9, allergic rhinitis in children, a positive family history of asthma and rhinitis and contact with cats were significantly associated with asthma, with adjusted ORs (95% CIs) of 3.05 (1.21 to 7.73), 2.83 (1.11 to 7.18), 10.5 (4.32 to 25.6), 2.65 (1.14 to 6.17), 2.49 (1.07 to 5.78) and 2.73 (1.03 to 7.27), respectively.
Conclusions:
This study did not find a statistically significant association between seropositivity to Toxocara sp. and risk of asthma in children. Low family income, low paternal education level, concomitant allergic rhinitis, family history of asthma and allergic rhinitis and contact with cats were independent factors associated with childhood asthma.
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