Prediction of Asthma by Common Risk Factors: A Follow-up Study in Cuban Schoolchildren

Objective: To determine which common risk factors, including environmental factors, are predictors for the development of asthma in Cuban schoolchildren. Methods: A longitudinal study was conducted in 1042 schoolchildren without asthma at baseline in 2 Cuban municipalities. Asthma status in 2007, diagnosed using the International Study of Asthma and Allergies in Childhood questionnaire, was related to a set of common risk factors assessed in 2003/2004 in a multivariable logistic regression model. Multiple imputation was used for missing values. The final prediction model was obtained by backward selection (P<.15). The model’s prognostic accuracy (R2) and discriminative ability (area under the receiver operating characteristic curve [AUC]) were assessed and internal validation by bootstrapping was performed. Results: A family history of atopic diseases (odds ratio [OR], 2.19; 95% CI, 1.19-4.04), allergic sensitization (OR, 1.83; 95% CI, 0.94-3.55), municipality (OR, 0.34; 95% CI, 0.15-0.74), and use of antibiotics in the child’s first year of life (OR, 1.66; 95% CI, 0.89-3.11) were predictors for asthma development. The model had an R2 of 8.0% and a moderate discriminative ability (AUC, 0.69; 95% CI, 0.60-0.78). Internal validation hardly influenced the model’s performance. Conclusions: Antibiotics use, genetic predisposition, and allergic sensitization were predictors of asthma in Cuban schoolchildren. Although known as common risk factors they could only partly predict asthma development. Poverty-related factors, such as low income and education, and parasitic infections, did not have an effect. Other or additional environmental predictors need to be identified, as these are potential targets for prevention and control of childhood asthma in affluent as well as nonaffluent countries (AU)

Objetivo: Determinar cuáles de los factores de riesgo habituales, incluyendo factores ambientales, tienen capacidad predictiva para el desarrollo de asma en población escolar cubana. Métodos: Estudio longitudinal realizado en una muestra de 1042 escolares cubanos, sin asma al comienzo del estudio, residentes en dos municipios. La presencia de asma en el año 2007, diagnosticada mediante el cuestionario ISAAC, se relacionó con la presencia de factores de riesgo habituales, presentes al inicio del estudio en los años 2003-2004 mediante un modelo de regresión logística multivariable. Se utilizó el criterio de imputación múltiple para los valores no registrados. El modelo final predictivo se obtuvo mediante selección retrógrada. Se evaluaron la capacidad predictiva del modelo (R cuadrada) y capacidad discriminante (Área bajo la curva ROC) y se realizó una validación interna mediante la técnica de muestreo “bootstrapping”. Resultados: Una historia familiar de enfermedades alérgicas (OR 2.19, 95%CI 1.19-4.04), la presencia de sensibilización frente a alérgenos comunes (OR 1.83, 95%CI 0.94-3.55), el municipio de residencia (OR 0.34, 95%CI 0.15-0.74), y el uso de antibióticos en el primer año del vida del niño (OR 1.66, 95%CI 0.89-3.11) fueron todos ellos factores predictivos del desarrollo de asma. La R cuadrada del modelo fue el 8,0% y poseía una moderada capacidad discriminativa (AUC 0.69, 95%CI 0.60-0.78). La validez interna influencia notablemente el funcionamiento del modelo. Conclusiones: Los antecedentes familiares de enfermedad alérgica, la sensibilización frente a alérgenos comunes y el uso de antibióticos en el primer año de vida fueron factores predictivos de la aparición de asma en los escolares cubanos, si bien solo fueron capaces de explicar en parte esta predisposición. Otros factores relacionados con un nivel socioeconómico bajo, como un nivel de ingresos o de educación bajos o las infecciones por parásitos, no tuvieron ningún efecto. Se hace por tanto necesario, identificar otros o adicionales factores predictivos ambientales, que sean también dianas de programas de prevención y control de la enfermedad asmática tanto en países de niveles económicos altos o bajos (AU)

Toxocara seropositivity, atopy and asthma: a study in Cuban schoolchildren.

INTRODUCTION: Evidence suggests that human toxocariasis (HT) could stimulate the onset of allergic diseases such as asthma. More specifically, in subjects having a hypothetical 'atopic genotype', HT could boost preexistent allergy symptoms. We tested the latter hypothesis in Cuba, a country where both asthma and HT are prevalent. MATERIAL AND METHODS: In a group of Cuban school-aged children (n = 958), we investigated the association of Toxocara seropositivity and atopic status with asthma. Toxocara seropositivity was diagnosed with ELISA and atopy by allergen skin prick test. Both physician-diagnosed asthma and current wheeze, as determined by International Study of Asthma and Allergies in Childhood (ISAAC) questionnaire, were considered. Associations were assessed using multivariable logistic regression analyses, with either 'physician-diagnosed asthma' or 'current wheeze' as outcome variable. RESULTS: 40.1% of the children were Toxocara seropositive. Prevalences were 21.7% for current wheeze and 32.7% for physician-diagnosed asthma. The odds of having asthma were almost two times higher in atopic children, but only reached borderline significance (OR=1.90, CI 95%: 0.95-3.80 for physician-diagnosed asthma and OR=1.94, CI 95%: 0.98-3.85 for current wheeze). Toxocara seropositivity and physician-diagnosed asthma were associated (OR=1.51, CI 95%: 1.01-2.26). Moreover, in children without antibodies to Toxocara, being atopic was significantly associated with having physician-diagnosed asthma (OR=2.53, CI 95%: 1.63-3.90), while this association was not present in Toxocara positives (OR=1.38, CI 95%: 0.82-2.37). CONCLUSION: Our data confirm previous observations of higher Toxocara seropositivity rates in asthmatic children. Toxocara seropositivity appeared to abrogate the apparent association between atopy and asthma in Cuban children. Although this observation was limited to physician-diagnosed asthma, it challenges the hypothesis that HT stimulates the onset of allergic diseases such as asthma in atopic individuals.

Prediction of asthma by common risk factors: a follow-up study in Cuban schoolchildren.

OBJECTIVE: To determine which common risk factors, including environmental factors, are predictors for the development of asthma in Cuban schoolchildren. METHODS: A longitudinal study was conducted in 1042 schoolchildren without asthma at baseline in 2 Cuban municipalities. Asthma status in 2007, diagnosed using the International Study of Asthma and Allergies in Childhood questionnaire, was related to a set of common risk factors assessed in 2003/2004 in a multivariable logistic regression model. Multiple imputation was used for missing values. The final prediction model was obtained by backward selection (P<.15). The model's prognostic accuracy (R2) and discriminative ability (area under the receiver operating characteristic curve [AUC]) were assessed and internal validation by bootstrapping was performed. RESULTS: A family history of atopic diseases (odds ratio [OR], 2.19; 95% CI, 1.19-4.04), allergic sensitization (OR, 1.83; 95% CI, 0.94-3.55), municipality (OR, 0.34; 95% CI, 0.15-0.74), and use of antibiotics in the child's first year of life (OR, 1.66; 95% CI, 0.89-3.11) were predictors for asthma development. The model had an R2 of 8.0% and a moderate discriminative ability (AUC, 0.69; 95% CI, 0.60-0.78). Internal validation hardly influenced the model's performance. CONCLUSIONS: Antibiotics use, genetic predisposition, and allergic sensitization were predictors of asthma in Cuban schoolchildren. Although known as common risk factors they could only partly predict asthma development. Poverty-related factors, such as low income and education, and parasitic infections, did not have an effect. Other or additional environmental predictors need to be identified, as these are potential targets for prevention and control of childhood asthma in affluent as well as nonaffluent countries.