Association of outdoor air pollution with the prevalence of asthma in children of Latin America and the Caribbean: A systematic review and meta-analysis.

OBJECTIVE: This study aimed to evaluate the association between asthma prevalence and outdoor air pollution in children in Latin America and the Caribbean. DATA SOURCES: We searched studies in global and regional databases: PubMed, Scopus, LILACS and SciELO. STUDY SELECTION: Articles following a cross-sectional design, studying children from 0 to 18 years old, and comparing the prevalence of asthma in two or more areas of LAC countries with different air pollution levels were included. The exclusion criteria comprised air pollution not related to human activities. RESULTS: Database searches retrieved 384 records, while 20 studies were retained for qualitative and 16 for quantitative analysis, representing 48 442 children. We found a positive association, i.e. a higher prevalence of asthma in children living in a polluted environment, with pooled odds ratio (OR) of 1.34 (95% CI: 1.17-1.54). Heterogeneity between studies was moderate (I2: 68.39%), while the risk of bias was intermediate or high in 14 studies. In all the subgroup and sensitivity analyses, the pooled ORs were significant and higher than those found in the general analysis Conclusions: Our results showed that living in a polluted environment is significantly associated with children having asthma in LAC. Limitations of this study include the low number of studies performed in LAC countries, differences in methodologies and the risk of bias in individual studies.

Effect of outdoor air pollution on asthma exacerbations in children and adults: Systematic review and multilevel meta-analysis.

BACKGROUND: Several observational studies have suggested that outdoor air pollution may induce or aggravate asthma. However, epidemiological results are inconclusive due to the presence of numerous moderators which influence this association. The goal of this study was to assess the relationship between outdoor air pollutants and moderate or severe asthma exacerbations in children and adults through a systematic review and multilevel meta-analysis. MATERIAL AND METHODS: We searched studies published in English on PubMed, Scopus, and Google Scholar between January 2000 and October 2016. Studies following a case-crossover design with records of emergency departments and/or hospital admissions as a surrogate of moderate or severe asthma exacerbations were selected. A multilevel meta-analysis was employed, taking into account the potential clustering effects within studies examining more than one lag. Odds ratios (ORs) and 95% confidence intervals were estimated. A subgroup analysis in children aged 0 to 18 years and a sensitivity analysis based on the quality of the included studies as defined in the Newcastle-Ottawa Scale were performed. Publication bias was evaluated through visual inspection of funnel plots and by a complementary search of grey literature. (Prospero Registration number CRD42015032323). RESULTS: Database searches retrieved 208 records, and finally 22 studies were selected for quantitative analysis. All pollutants except SO2 and PM10 showed a significant association with asthma exacerbations (NO2: 1.024; 95% CI: 1.005,1.043, SO2: 1.039; 95% CI: 0.988,1.094), PM10: 1.024; 95% CI: 0.995,1.053, PM2.5: 1.028; 95% CI: 1.009,1.047, CO: 1.045; 95% CI: 1.005,1.086, O3: 1.032; 95% CI: 1.005,1.060. In children, the association was significant for NO2, SO2 and PM2.5. CONCLUSION: This meta-analysis provides evidence of the association between selected air pollutants and asthma exacerbations for different lags.

Efecto de la temperatura en las exacerbaciones de asma y enfermedad pulmonar obstructiva crónica (EPOC) / Effect of temperature on exacerbations of asthma and chronic obstructive pulmonary disease (COPD)

INTRODUCCIÓN Las enfermedades pulmonares obstructivas, entre ellas el asma y la enfermedad pulmonar obstructiva crónica (EPOC), representan una alta carga de enfermedad afectando a más de 500 millones de personas a nivel global. Existen diversos factores de riesgo para las exacerbaciones de estas enfermedades. La temperatura ambiente ha sido una variable poco estudiada, aunque se sabe que puede actuar en forma directa o indirecta en estos cuadros. OBJETIVO Evaluar la influencia de la temperatura en las exacerbaciones por asma y EPOC en población hospitalaria. MÉTODOS Se realizó en San Nicolás, provincia de Buenos Aires, un estudio observacional analítico de tipo casos cruzados. Se seleccionaron pacientes concurrentes al servicio de neumonología del hospital público de la ciudad, y se realizó un seguimiento de 8 meses con administración de una encuesta periódica donde se consultó sobre las visitas a emergencias u hospitalizaciones por exacerbaciones. Estas visitas fueron relacionadas con datos de temperatura y otras co-variables ambientales e individuales, comparando el período de la exacerbación con periodos de control. Se utilizó un modelo de regresión logística condicional y se calcularon los odds ratio (OR) como medidas de asociación. RESULTADOS Se registraron 153 visitas entre consultas, concurrencia a emergencias u hospitalizaciones, correspondientes a 79 pacientes. Un descenso en la temperatura mínima dos días previos a la exacerbación fue identificado como factor de riesgo de exacerbaciones, cuando se controló por humedad y velocidad del viento (OR: 1,16; IC95%: 1,01­1,33; p<0,05). Esta asociación fue mayor en otoño y en personas no expuestas al humo del tabaco. DISCUSIÓN Los resultados de este estudio demuestran la relación entre el descenso de la temperatura mínima y las exacerbaciones por asma y EPOC, a la vez que aportan datos valiosos para el desarrollo de guías o información de prevención para el manejo de estas enfermedades