Plaguicidas en alimentos: riesgo a la salud y marco regulatorio en Veracruz, México / Pesticide residues in food: health risk and regulation in Veracruz, Mexico

Resumen: Objetivo: Evaluar el cumplimiento de los límites máximos permisibles de residuos de plaguicidas en alimentos del estado de Veracruz, así como evaluar el riesgo para la salud humana debido a su consumo. Material y métodos: Se midieron las concentraciones de residuos de plaguicidas en productos vegetales y se compararon con los valores establecidos como límites de seguridad en el marco regulatorio del uso de plaguicidas. Se calculó el cociente de peligro y sus posibles efectos a la salud. Resultados: El 14.8% de las muestras excedieron la concentración permitida. Se detectaron plaguicidas prohibidos (metamidofos, monocrotofos, triazofos y clorpirifos) que superaron las dosis de referencia establecidas, lo que pone en riesgo de sufrir posibles efectos a la salud del tipo neurológico, hepatotóxico y alteraciones endocrinas a la población. Conclusiones: Se encontraron residuos de plaguicidas altamente peligrosos en los alimentos, los cuales están prohibidos por los convenios internacionales ambientales derivado de su potencial para causar efectos a la salud y al medio ambiente, por lo cual es necesario su eliminación. El marco regulatorio de México debe actualizarse y ser dinámico conforme se avance en el conocimiento de los efectos adversos de los plaguicidas en la salud.

Abstract: Objective: Evaluate compliance with the maximum permissible limits for pesticide residues in food in the state of Veracruz, as well as the risk to human health due to its consumption. Materials and methods: The concentration of pesticide residues in plant products were measured for comparison with the values established as safety limits and the regulatory framework for the use of pesticides. The hazard quotient and its possible effect on health were calculated. Results: 14.8% of the samples exceeded the allowed concentration. We found banned pesticides (methamidophos, monochotophos, triazophos and chlorpyrifos) that exceeded the established references dose, which increase the risk of possible neurological, hepatotoxic and endocrine alterations in health. Conclusions: There is the presence of highly hazardous pesticides, which are prohibited by international environmental conventions due to their impact on health and the environment, which is why their elimination is necessary. The regulatory framework in Mexico must be updated and dynamic as the knowledge of the adverse health effects of pesticides advances.

[Pesticide residues in food: health risk and regulation in Veracruz, Mexico]. / Plaguicidas en alimentos: riesgo a la salud y marco regulatorio en Veracruz, México.

Objective. Evaluate compliance with the maximum permissible limits for pesticide residues in food in the state of Veracruz, as well as the risk to human health due to its consumption. Materials and methods. The concentration of pesticide residues in plant products were measured for comparison with the values established as safety limits and the regulatory framework for the use of pesticides. The hazard quotient and its possible effect on health were calculated. Results. 14.8% of the samples exceeded the allowed concentration. We found banned pesticides (methamidophos, monochotophos, triazophos and chlorpyrifos) that exceeded the established references dose, which increase the risk of possible neurological, hepatotoxic and endocrine alterations in health. Conclusions. There is the presence of highly hazardous pesticides, which are prohibited by international environmental conventions due to their impact on health and the environment, which is why their elimination is necessary. The regulatory framework in Mexico must be updated and dynamic as the knowledge of the adverse health effects of pesticides advances.

Prenatal exposure to environmental pollutants and child development trajectories through 7 years.

BACKGROUND: Prenatal exposure to environmental pollutants such as mold, lead, pesticides, tobacco, and air pollutants has been suggested to impair cognitive development. Evidence is needed from longitudinal studies to understand their joint impact on child development across time. OBJECTIVE: To study associations between exposure to indoor environmental pollutants or outdoor air pollution during pregnancy and offspring cognitive development trajectories through 7 years. METHODS: We included 718 Mexican mother-child pairs. Prenatal exposure to indoor environmental pollutants (mold, ventilation, pesticides, tobacco smoke, and use of vidiartred clay pots) was self-reported by the mothers and integrated into an index, or objectively measured in the case of outdoor air pollutants (nitrogen oxides, benzene, toluene, and xylene). Child global cognitive development was measured at 12, 18, 60, or 84 months. Using Latent Class Growth Analysis, we identified three developmental trajectories (positive = 108, average = 362, low = 248). We used multinomial logistic models to test associations between environmental pollutant score (EPS) or outdoor air pollutants, and cognitive development trajectories. RESULTS: After adjustment for sociodemographic covariates, EPS was associated with the average (OR = 1.26 95%CI = 1.01, 1.55) and low (OR = 1.41 95%CI = 1.11, 1.79) trajectories compared to positive; where a unit increase in EPS means an additional prenatal exposure to a pollutant. There was no association between outdoor air pollutants and cognitive development trajectories. CONCLUSION: Children of women who reported higher exposure to indoor environmental pollutants during pregnancy were more likely to follow worse developmental trajectories through 7 years. These results support the development and testing of interventions to reduce exposure to environmental pollutants during pregnancy and early childhood as a potential strategy to improve long-term cognitive development.

Exposición a Bisfenol A (BPA) en mujeres embarazadas y su relación con la obesidad en sus hijos: Revisión Sistemática / Pregnant Women's Exposure to Bisphenol A (BPA) and its Relation to their Children's Obesity: A systematic Review / Exposição ao bisfenol a (BPA) em mulheres engravidadas e a sua relação com a obesidade em seus filhos: uma revisão sistemática

Resumen Introducción: El bisfenol A (BPA) es un contaminante químico no persistente que altera el funcionamiento normal del sistema endocrino. Se sugiere que la exposición prenatal a BPA se asocia con la obesidad en la descendencia. Objetivo: Revisar la literatura sobre la exposición al BPA en mujeres embarazadas y su relación con la obesidad en sus hijos. Metodología: Revisión sistemática de acuerdo a la guía PRISMA, donde se realizaron búsquedas en las bases de datos Pubmed, ScienceDirect, Clinical Key, Medline, Ebsco y Scielo y el motor de búsqueda Google Scholar hasta 30 de abril de 2017 por dos investigadores independientes que utilizaron iguales términos de búsqueda. Se incluyeron estudios prospectivos de cohorte realizados que midieron el BPA en la orina materna. Resultados: Se incluyeron 5 estudios con tamaños de muestra que varían entre 297 y 757 binomios madre e hijo, se encontró asociación positiva entre la exposición prenatal a BPA con la circunferencia de cintura en niños de cuatro años β: 0.28 (IC95%:0.01 a 0.57) y el índice de masa grasa β: 0.31 (IC95%: 0.01 a 0.60) en dos de los estudios. Además, se observaron asociaciones positivas y/o negativas no significativas con índice de masa corporal y su puntaje Z, porcentaje de grasa, sobrepeso/obesidad, peso y talla al nacer, porcentaje de masa grasa. Conclusión: Los resultados del cuerpo existente de estudios epidemiológicos de cohorte, limita las afirmaciones sobre un vínculo causal entre la exposición prenatal BPA y la obesidad postnatal.

Abstract Introduction: Bisphenol A (BPA) is a non-persistent chemical pollutant which alters the normal functioning of the endocrine system. It is suggested that prenatal exposure is related to descendant obesity. Objective: Review literature on pregnant women's exposure to BPA and the relation to their children's obesity. Methodology: Systematic review in accordance with PRISMA guidelines. Searches were conducted on databases including Pubmed, ScienceDirect, Clinical Key, Medline, Ebsco and Scielo and Google Scholar search engine until April 30, 2017 by two independent researchers that used the same search terms. Prospective cohort conducted studies were included because they measured BPA in maternal urine. Results: Five studies were included with sample sizes ranging from 297 to 757 mother-child binomials. The review found a positive association between prenatal BPA exposure with 4-year-old children's waist circumference β: 0.28 (95% CI :0.01 to 0.57) and the fat mass index β: 0.31 (95%CI: 0.01 to 0.60) in two of the studies. non-significant positive and/or negative associations where observed with body mass index z-scores, overweight/ obesity, weight and size at birth, body mass percentage. Conclusion: The results of cohort epidemiological studies constrain statements regarding a causal link between prenatal BPA exposure and postnatal obesity.

Resumo Introdução: O bisfenol A (BPA) é um contaminante químico não persistente que altera o funcionamento normal do sistema endócrino. Se sugere que a exposição pré-natal se associa com a obesidade na descendência. Objetivo: Revisar a literatura sobre a exposição ao BPA em mulheres engravidadas e a sua relação com a obesidade em seus filhos. Metodologia: Revisão sistemática de acordo com a guia PRISMA. Se realizaram pesquisas nas bases de dados Pubmed, ScienceDirect, Clinical Key, Medline, Ebsco e Scielo e o motor de pesquisa Google Scholar até o 30 de Abril de 2017 por dois investigadores independentes que utilizaram os mesmos termos de busca. Se incluíram estudos prospectivos de coorte realizados que calcularam o BPA na urina materna. Resultados: Se incluíram 5 estudos com tamanhos de amostra entre 297 e 757 binômios mãe e filho, se encontrou associação positiva entre a exposição pré-natal a BPA com a circunferência de cintura em meninos de quatro anos β: 0.28 (IC95%:0.01 a 0.57) e o índice de massa de gordura β: 0.31 (IC95%: 0.01 a 0.60) em dois dos estudos. Se enxergaram associações positivas e/ou negativas não significativas com índice de massa corporal e a sua pontuação Z, porcentagem de gordura, sobrepeso/obesidade, peso e dimensão ao nascer, porcentagem de massa de gordura. Conclusão: Os resultados de estudos epidemiológicos de coorte, limita as afirmações sobre um vínculo causal entre a exposição pré-natal BPA e a obesidade pós-natal.

Estrés oxidativo, función pulmonar y exposición a contaminantes atmosféricos en escolares mexicanos con y sin asma / Oxidative stress, lung function and exposure to air pollutants in Mexican schoolchildren with and without asthma

Resumen: Objetivo: Evaluar la asociación entre la exposición a contaminantes atmosféricos y marcadores de estrés oxidativo, por un lado, y la función pulmonar, por el otro, en escolares, con y sin asma, de las ciudades de Salamanca y León, en Guanajuato, México. Material y métodos: Se realizaron determinaciones de marcadores de estrés oxidativo y pruebas de función pulmonar en 314 escolares, y se obtuvo información sobre contaminantes atmosféricos (ozono, dióxido de azufre, monóxido de carbono y partículas menores de 2.5 µm y menores de 10 µm) de las estaciones de monitoreo correspondientes. Para evaluar la asociación se corrieron modelos de regresión lineal múltiple. Resultados: Con un día de retraso a la exposición a partículas menores de 10 µm (PM10), se observó un incremento de 0.09 pmol en los dienos conjugados entre niños asmáticos de Salamanca (p<0.05). La exposición a ozono durante el mismo día incrementó la concentración de lipo-hidroperóxidos en 4.38 nmol entre asmáticos de Salamanca, así como en 2.31 nmol por la exposición a PM10 para dos días de retraso (p<0.05). La capacidad vital forzada disminuyó 138 y 203 ml en niños sin asma, respectivamente, por la exposición a monóxido de carbono (p<0.05). Conclusiones: La exposición a contaminantes atmosféricos incrementa el estrés oxidativo y disminuye la función pulmonar en escolares con y sin asma.

Abstract: Objective. To assess the association between the air pollutants exposure on markers of oxidative stress and lung function in schoolchildren with and without asthma from Salamanca and Leon Guanajuato, Mexico. Materials and methods: We realized determinations of oxidative stress biomarkers and lung function tests in 314 schoolchildren. Information of air pollutants (O3, SO2, CO, PM2.5 and PM10) were obtained from monitoring stations and multiple linear regression models were run to assess the association. Results: An increase of 0.09 pmol in conjugated dienes was observed by exposure to PM10 lag 1 in asthmatics from Salamanca (p<0.05). The exposure to O3 during the same day increased the concentration of Lipohydroperoxides in 4.38 nmol in asthmatics of Salamanca, as well as in 2.31 nmol by exposure to PM10 lag 2 (p<0.05). The forced vital capacity decreased by 138 and 203 ml in children without asthma, respectively, due to exposure to carbon monoxide (p<0.05). Conclusions: Exposure to air pollutants increase oxidative stress and decreased lung function in schoolchildren, with and without asthma.

Effect of particulate matter less than 10µm (PM10) on mortality in Bogota, Colombia: a time-series analysis, 1998-2006 / Efecto del material particulado menor a 10µm (PM10) sobre la mortalidad en Bogotá, Colombia: un análisis de series de tiempo 1998-2006

Objective. To analyze the association between daily mortality from different causes and acute exposure to particulate matter less than 10 microns in aerodynamic diameter (PM10), in Bogota, Colombia. Materials and methods. A time-series ecological study was conducted from 1998 to 2006. The association between mortality (due to different causes) and exposure was analyzed using single and distributed lag models and adjusting for potential confounders. Results. For all ages, the cumulative effect of acute mortality from all causes and respiratory causes increased 0.71% (95%CI 0.46-0.96) and 1.43% (95%CI 0.85-2.00), respectively, per 10µg/m³ increment in daily average PM10 with a lag of three days before death. Cumulative effect of mortality from cardiovascular causes was -0.03% (95%CI -0.49-0.44%) with the same lag. Conclusions. The results suggest an association between an increase in PM10 concentrations and acute mortality from all causes and respiratory causes.

Objetivo. Analizar la asociación entre la mortalidad diaria debida a distintas causas y la exposición aguda a partículas menores de 10 micras de diámetro aerodinámico (PM10), en Bogotá, Colombia. Material y métodos. Se realizó un estudio ecológico de series de tiempo (1998-2006). La asociación entre mortalidad y exposición se analizó ajustando modelos de retraso simple y retraso distribuido para diferentes causas de mortalidad. Resultados. En todas las edades, el riesgo acumulado en la mortalidad aguda por todas las causas y causa respiratoria aumentó 0.71% (IC95% 0.46-0.96) y 1.43% (IC95% 0.85-2.00), respectivamente, por incremento de 10µg/m³ en el promedio diario de PM10, tomando un retraso de tres días anteriores al deceso, mientras el riesgo acumulado en la mortalidad por causa cardiovascular fue de -0.03% (IC95% -0.49-0.44), para el mismo retraso. Conclusiones. Los resultados sugieren asociación entre el incremento de las concentraciones de PM10 y la mortalidad aguda por todas las causas y causa respiratoria.

Effect of socioeconomic status on the association between air pollution and mortality in Bogota, Colombia / Efecto del nivel socioeconómico sobre la asociación entre contaminantes atmosféricos y mortalidad en Bogotá, Colombia

Objective. To evaluate the modification effect of socioeconomic status (SES) on the association between acute exposure to particulate matter less than 10 microns in aerodynamic diameter (PM10) and mortality in Bogota, Colombia. Materials and methods. A time-series ecological study was conducted (1998-2006). The localities of the cities were stratified using principal components analysis, creating three levels of aggregation that allowed for the evaluation of the impact of SES on the relationship between mortality and air pollution. Results. For all ages, the change in the mortality risk for all causes was 0.76% (95%CI 0.27-1.26) for SES I (low), 0.58% (95%CI 0.16-1.00) for SES II (mid) and -0.29% (95%CI -1.16-0.57) for SES III (high) per 10µg/m³ increment in the daily average of PM10 on day of death. Conclusions. The results suggest that SES significantly modifies the effect of environmental exposure to PM10 on mortality from all causes and respiratory causes.

Objetivo. Evaluar el efecto modificador del nivel socioeconómico (NSE) sobre la asociación entre la exposición aguda a partículas menores de 10 micras de diámetro aerodinámico (PM10) y la mortalidad en Bogotá, Colombia. Material y métodos. Se realizó un estudio ecológico de series de tiempo (1998-2006). Mediante análisis de componentes principales se estableció una estratificación de las localidades de la ciudad, de lo que se generaron tres niveles de agregación que permitieron evaluar el impacto de la variable NSE en la relación mortalidad-contaminación atmosférica. Resultados. En todas las edades, para la mortalidad por todas las causas, el porcentaje de cambio en el riesgo fue 0.76% (IC95% 0.27-1.26) en el NSE I (bajo), 0.58% (IC95% 0.16-1.00) en el NSE II (medio) y -0.29% (IC95% -1.16-0.57) en el NSE III (alto), por incremento de 10µg/m³ en el promedio diario de PM10 en el día del deceso. Conclusiones. Los resultados sugieren que el NSE modifica de manera significativa el efecto de la exposición ambiental a PM10 sobre la mortalidad por todas las causas y causas respiratorias.

Modulation of DNA methylation states and infant immune system by dietary supplementation with ω-3 PUFA during pregnancy in an intervention study.

BACKGROUND: Early-life exposures to tobacco smoke and some dietary factors have been identified to induce epigenetic changes in genes involved in allergy and asthma development. Omega-3 (n-3) polyunsaturated fatty acid (PUFA) intake during pregnancy could modulate key cytokines and T helper (Th) cell maturation; however, little is known about the mechanism by which ω-3 PUFA could have a beneficial effect in preventing inflammatory disorders. OBJECTIVE: We sought to test whether prenatal dietary supplementation with ω-3 PUFA during pregnancy may modulate epigenetic states in the infant immune system. DESIGN: This study was based on a randomized intervention trial conducted in Mexican pregnant women supplemented daily with 400 mg docosahexaenoic acid (DHA) or a placebo from 18 to 22 wk of gestation to parturition. We applied quantitative profiling of DNA methylation states in Th1, Th2, Th17, and regulatory T-relevant genes as well as LINE1 repetitive elements of cord blood mononuclear cells (n = 261). RESULTS: No significant difference in promoter methylation levels was shown between ω-3 PUFA-supplemented and control groups for the genes analyzed; however, ω-3 PUFA supplementation was associated with changes in methylation levels in LINE1 repetitive elements (P = 0.03) in infants of mothers who smoked during pregnancy. Furthermore, an association between the promoter methylation levels of IFNγ and IL13 was modulated by ω-3 PUFA supplementation (P = 0.06). CONCLUSIONS: Our results indicate that maternal supplementation with ω-3 PUFA during pregnancy may modulate global methylation levels and the Th1/Th2 balance in infants. Therefore, the epigenetic mechanisms could provide attractive targets for prenatal modulation and prevention of inflammatory disorders and potentially other related diseases in childhood and adulthood.

Reference ranges for Mexican preschool-aged children using the forced oscillation technique.

INTRODUCTION: Recently, multi-ethnic reference ranges for spirometry have been created for use worldwide. In comparison, forced oscillation technique (FOT) reference values are limited to specific equipment and study populations, with current FOT reference ranges created in a Caucasian population. We aimed to develop FOT reference ranges for preschool-aged Mexican children and to compare these with current FOT reference ranges. PATIENTS AND METHODS: Respiratory resistance (Rrs) and reactance (Xrs) was measured in healthy Mexican children three to five years of age using commercial FOT equipment. The relationship between height and Rrs and Xrs was determined using regression analyses, taking into account age, weight, sex, and exposure to tobacco smoke. Reference equations were calculated for the Mexican children and Z-scores determined for Rrs and Xrs at 6 and 8Hz. A paired t-test assessed the difference in Z-scores between the Australian reference values and those created for the Mexican cohort. RESULTS: FOT was successfully measured in 584 children. Height was a significant predictor of Rrs and Xrs at 6 and 8Hz (P<.05). Z-scores calculated using the Australian reference equations overestimated lung function in Mexican children for both Rrs and Xrs at 6 and 8Hz (P<.001). CONCLUSION: The development of FOT reference ranges specific to Mexican preschool-aged children will allow for the correct interpretation of FOT measurements. This study also showed that current FOT reference ranges overestimate lung function in Mexican children. Highlighting, the importance of using ethnic appropriate reference ranges for interpreting lung function.

Association between light absorption measurements of PM2.5 and distance from heavy traffic roads in the Mexico City metropolitan area / Asociación entre las mediciones de PM2.5 por absorbancia y la distancia a vías de alto tráfico en la zona metropolitana de la Ciudad de México

OBJECTIVE: To study the relationship between light absorption measurements of PM2.5 at various distances from heavy traffic roads and diesel vehicle counts in Mexico City. MATERIALS AND METHODS: PM2.5 samples were obtained from June 2003-June 2005 in three MCMA regions. Light absorption (b abs) in a subset of PM2.5 samples was determined. We evaluated the effect of distance and diesel vehicle counts to heavy traffic roads on PM2.5 b abs using generalized estimating equation models. RESULTS: Median PM2.5 b abs measurements significantly decrease as distance from heavy traffic roads increases (p<0.002); levels decreased by 7% (CI95% 0.9-14) for each 100 additional meters from heavy traffic roads. Our model predicts that PM2.5 b abs measurements would increase by 20% (CI95% 3-38) as the hourly heavy diesel vehicle count increases by 150 per hour. CONCLUSION: PM2.5 b abs measurements are significantly associated with distance from motorways and traffic density and therefore can be used to assess human exposure to traffic-related emissions.

OBJETIVO: Evaluar la relación entre las mediciones de absorción de luz de las PM2.5 a diferentes distancias de vías de tráfico y el aforo vehicular de diesel en la Ciudad de México. MATERIAL Y MÉTODOS: Se realizaron mediciones de PM2.5 y su análisis de b abs en tres zonas de la Ciudad de México. Se usaron modelos GEE para evaluar el efecto de la distancia y el aforo vehicular de tráfico pesado sobre PM2.5 b abs. RESULTADOS: Se observó una tendencia decreciente en la mediana de PM2.5 b abs conforme se incrementó la distancia a las avenidas de alto tráfico (p<0.002); los niveles decrecen en 7% (CI95% 0.9-14) por cada 100 metros de incremento. Las mediciones de PM2.5 b abs se incrementan en 20% (CI95% 3-38) cuando el aforo vehicular a diesel es mayor de 150 en una hora. CONCLUSIONES: Las mediciones de PM2.5 b abs están significativamente asociadas con la distancia de avenidas con alto tránsito vehicular y con vehículos de diesel.

Consumo de alimentos y asma en niños escolares de Cuernavaca / Food consumption and asthma in school children in Cuernavaca, Morelos, Mexico

OBJETIVO:Evaluar la relación entre la dieta y el desarrollo de asma y rinitis alérgica en escolares de Cuernavaca, Morelos, México. MATERIAL Y MÉTODOS: Se aplicó el cuestionario ISAAC (International Study of Asthma and Allergies in Childhood) a 5 460 niños de entre 6 a 8 y 11 a 14 años de edad, de nivel primaria, seleccionados de manera aleatoria. Se formaron seis grupos de alimentos a partir de un análisis de clusters jerárquico y se evaluó la relación con los padecimientos a través de modelos de regresión logística. RESULTADOS:El consumo de comida rápida tuvo un efecto adverso sobre la sibilancia actual (RM=1.82; IC95%=1.16-2.87) y el consumo de golosinas sobre más de tres episodios de sibilancia (RM=2.26; IC95%=1.04-4.95) y síntomas nasales sin gripa o catarro (RM=1.35; IC95%=1.06-1.71). CONCLUSIONES:Este estudio provee evidencia de que la dieta juega un papel muy importante, ya que el consumo abundante de comida rápida y golosinas incrementa el riesgo de asma y rinitis.

OBJECTIVE:To evaluate the relation between diet and the development of asthma and allergic rhinitis in schoolchildren from Cuernavaca, Morelos, Mexico. MATERIAL AND METHODS:We apply the ISAAC's questionnaire in 5460 schoolchildren from 6 to 8 and 11-14-year-old of elementary level selected in random form. Six groups of food were formed using a hierarchic clusters analysis and the association was evaluated using logistic regression models. RESULTS:The consumption of fast food had an adverse effect for current wheezing (OR=1.82; CI95%=1.16-2.87) and the consumption of tidbits for more than three episodes of wheezing (OR=2.26; CI95%=1.04-4.95) and nasal symptoms without cold, OR=1.35 (IC95%;1.06-1.71). CONCLUSIONS:This study provides evidence that the diet plays a very important role since the high consumption of fast food and tidbits increased the risk of asthma and rhinitis symptoms.

Efecto del ambiente rural sobre la prevalencia de rinitis alérgica en escolares de Mexicali, Baja California, México / The effects of a rural environment on the prevalence of allergic rhinitis among schoolchildren in Mexicali, Baja California, Mexico

OBJETIVOS: Determinar la prevalencia de síntomas de rinitis alérgica en escolares de Mexicali, Baja California, México, y evaluar la influencia del medio ambiente rural sobre esta afección. MÉTODOS: Estudio transversal poblacional mediante la aplicación de un cuestionario estandarizado en una muestra aleatoria de 2 087 escolares de 6 a 7 años (1 078 niñas y 1 009 niños) residentes en la ciudad de Mexicali, Baja California, México. Se evaluó la asociación entre variables de exposición y antecedentes clínicos personales y familiares, y dos variables dependientes: síntomas nasales y síntomas nasales y oculares, en ausencia de catarro o gripe, con sus razones de posibilidades (OR, odds ratios) e intervalos de confianza de 95 por ciento (IC95 por ciento). El estudio, realizado entre febrero y julio de 2004, utilizó la metodología del Estudio Internacional de Asma y Alergia en la Infancia (ISAAC). RESULTADOS: Las prevalencias generales de síntomas nasales y síntomas nasales y oculares fueron de 25,0 por ciento y 10,5 por ciento, respectivamente. Los niños y las niñas que habían vivido en el campo o zona rural en algún momento presentaron menor probabilidad de padecer síntomas nasales (OR = 0,43; IC95 por ciento: 0,24 a 0,77) y síntomas nasales y oculares (OR = 0,39; IC95 por ciento: 0,16 a 0,93), después de ajustar por factores de confusión. CONCLUSIONES: El contacto con el medio rural en los primeros años de vida disminuyó el riesgo de presentar rinitis alérgica en la población estudiada, independientemente de los antecedentes familiares de asma.

OBJECTIVES: To assess the prevalence of allergic rhinitis symptoms among schoolchildren in Mexicali, Baja California, Mexico, and determine what impact a rural environment might have on this condition. METHODS: A population-based, cross-sectional study using a standardized questionnaire administered to a random sample of 2 087 schoolchildren 6-7 years of age (1 078 girls and 1 009 boys) living in the city of Mexicali, Baja California, Mexico. The study analyzed associations between exposure variables and personal and family health history, and two dependent variables-nasal symptoms and nasal and ocular symptoms, in the absence of a cold or flu-using odd ratios (OR) and 95 percent Confidence Intervals (95 percentCI). The study took place in February-July 2004 and followed the methodology of the International Study of Asthma and Allergies in Childhood (ISAAC). RESULTS: The general prevalence of nasal symptoms and nasal and ocular symptoms was 25.0 percent and 10.5 percent, respectively. The boys and girls who had ever lived on a farm or in a rural area had a lower probability, adjusted for confounding variables, of presenting nasal symptoms (OR = 0.43; 95 percentCI: 0.24-0.77), or nasal and ocular symptoms (OR = 0.39; 95 percentCI: 0.16-0.93). CONCLUSIONS: In the study population, exposure to a rural environment in early childhood decreased the risk of developing allergic rhinitis, regardless of a family history of asthma.

Air pollution, airway inflammation, and lung function in a cohort study of Mexico City schoolchildren.

BACKGROUND: The biological mechanisms involved in inflammatory response to air pollution are not clearly understood. OBJECTIVE: In this study we assessed the association of short-term air pollutant exposure with inflammatory markers and lung function. METHODS: We studied a cohort of 158 asthmatic and 50 nonasthmatic school-age children, followed an average of 22 weeks. We conducted spirometric tests, measurements of fractional exhaled nitric oxide (Fe(NO)), interleukin-8 (IL-8) in nasal lavage, and pH of exhaled breath condensate every 15 days during follow-up. Data were analyzed using linear mixed-effects models. RESULTS: An increase of 17.5 microg/m(3) in the 8-hr moving average of PM(2.5) levels (interquartile range) was associated with a 1.08-ppb increase in Fe(NO) [95% confidence interval (CI), 1.01-1.16] and a 1.07-pg/mL increase in IL-8 (95% CI 0.98-1.19) in asthmatic children and a 1.16 pg/ml increase in IL-8 (95% CI, 1.00-1.36) in nonasthmatic children. The 5-day accumulated average of exposure to particulate matter <2.5 microm in aerodynamic diamter (PM(2.5)) was significantly inversely associated with forced expiratory volume in 1 sec (FEV(1)) (p=0.048) and forced vital capacity (FVC) (p=0.012) in asthmatic children and with FVC (p=0.021) in nonasthmatic children. Fe(NO) and FEV(1) were inversely associated (p=0.005) in asthmatic children. CONCLUSIONS: Exposure to PM(2.5) resulted in acute airway inflammation and decrease in lung function in both asthmatic and nonasthmatic children.

Assessment of personal exposure to ozone in asthmatic children residing in Mexico City / Evaluación de la exposición personal a ozono en niños asmáticos de la Ciudad de México

OBJECTIVE: A study was conducted to evaluate personal ozone exposure (O3p) among asthmatic children residing in Mexico City. MATERIAL AND METHODS: A total of 158 chil-dren were recruited from December 1998 to April 2000. On average, three O3p measurements were obtained per child using passive badges. Time-activity patterns were recorded in a diary. Daily ambient ozone measurements (O3a) were obtained from the fixed station, according to children’s residence. Levels of O3a and ozone, weighted by time spent in different micro-environments (O3w), were used as independent variables in order to model O3p concentrations using a mixed-effects model. RESULTS: Mean O3p was 7.8 ppb. The main variables in the model were: time spent indoors, distance between residence and fixed station, follow-up group, and two interaction terms (overall R²=0.50, p<0.05). CONCLUSIONS: The O3w concentrations can be used as a proxy for O3p, taking into account time-activity patterns and the place of residence of asthmatic Mexican children.

OBJETIVO: Realizamos este estudio para evaluar la exposición personal a ozono (O3p) en niños asmáticos de la Ciudad de México. MATERIAL Y MÉTODOS: Se incluyeron 158 niños entre diciembre de 1998 y abril de 2000. En promedio se obtuvieron tres mediciones por niño, utilizando filtros pasivos para medir O3p. Se caracterizaron los patrones de actividad y las concentraciones ambientales diarias de ozono (O3a) se obtuvieron de estaciones fijas cercanas a la residencia del niño. Los niveles promedio de O3a y las concentraciones ponderadas por el tiempo en diferentes microambientes (O3w) fueron usados como variables independientes para modelar las concentraciones de O3p, utilizando modelos de efectos mixtos. RESULTADOS: La media de O3p fue 7.8 ppb. Las principales variables en el modelo fueron: tiempo en exteriores, distancia, periodo de seguimiento y dos términos de interacción (R²=0.50, p<0.05). CONCLUSIONES: Las concentraciones de O3w pueden usarse como "proxi" de O3p, tomando en cuenta patrones de actividad y lugar de residencia.

Validez en el registro del pico espiratorio máximo de niños asmáticos de la Ciudad de México / Validity of peak flow record in asthmatic children residing in Mexico City

OBJETIVO: Determinar la concordancia entre el pico espiratorio forzado (PEF) registrado por padres de niños asmáticos y el PEF electrónico que es el almacenado en el AirWatch (PEFe). MATERIAL Y MÉTODOS: Se obtuvo el PEF de 42 niños de 5 a 15 años de edad del Hospital Infantil de México Federico Gómez de la Ciudad de México entre octubre de 1998 y 1999. Los padres registraron el valor máximo del PEF en un diario de salud. Se calculó la correlación de Spearman entre el PEFe y el PEFr. Utilizamos un modelo logístico de efectos mixtos. RESULTADOS: La correlación del PEFe y el PEFr fue r= 0.96 (p<0.05) en niños con diagnóstico de asma moderada o severa y r= 0.40 (p< 0.05) en niños con asma leve. El tiempo de seguimiento y severidad del asma, el género y edad del niño y sus interacciones eran predictores de las diferencias entre el PEFe y el PEFr. CONCLUSIONES: Los padres de niños de 6 a 8 años con asma moderada o severa reportan mejor el PEF en el diario de salud a lo largo del seguimiento que los padres de otros grupos.

OBJECTIVE: To determine the concordance between maximum peak expiratory flow records (PEFr) reported by the parents of asthmatic children and the electronic values stored by the AirWatch device (PEFe). MATERIAL AND METHODS: Records of PEF measurements between October 1998 and 1999 were obtained from 42 asthmatic children 5 to 15 years of age recruited at the Hospital Infantil de Mexico Federico Gomez, in Mexico City. Parents recorded the maximum value in the health diary. Spearman correlation was calculated between PEFe and PEFr and a mixed-effects logistic model was used. RESULTS: The correlation between PEFe and PEFr was r=0.96 (p<0.05) among children with a diagnosis of moderate or severe asthma and r=0.40 (p<0.05) among children diagnosed with mild asthma. Follow-up time, asthma severity, gender and age of the child and their interactions were predictors of the differences between PEFe and PEFr. CONCLUSIONS: Parents of children with moderate or severe asthma from 6 to 8 years of age report PEF values with greater accuracy during follow-up than others.

Morbilidad infantil por causas respiratorias y su relación con la contaminación atmosférica en Ciudad Juárez, Chihuahua, México / Infant morbidity caused by respiratory diseases and its relation with the air pollution in Juarez City, Chihuahua, Mexico

OBJETIVO: Evaluar el impacto de los contaminantes atmosféricos sobre la salud respiratoria de la población infantil de Ciudad Juárez, Chihuahua, México, considerando diferentes grupos etáreos. MATERIAL Y MÉTODOS: Se obtuvieron datos sobre consultas a urgencias de hospitales por afecciones de vías respiratorias altas, bajas y asma, en unidades del IMSS, de niños menores de 17 años de edad entre 1997 y 2001, y se estratificó por grupos etáreos (<5 años y >5 años). Se obtuvieron datos diarios sobre contaminantes aéreos (Ozono y PM10) y condiciones meteorológicas de la Red de Monitoreo en Ciudad Juárez. Para el análisis estadístico de los datos, se utilizó un Modelo Aditivo Generalizado, asumiendo una distribución de Poisson. RESULTADOS: Las concentraciones de ozono, pero no de PM10, se asociaron significativamente con las consultas a urgencias por afecciones respiratorias, principalmente en niños de 5 años o menores. En este grupo, un incremento de 20 ppb en 1 hr máxima de ozono se asociaron con un incremento de 8.3 por ciento en las consultas por afecciones de vías respiratorias superiores, con un retraso en la exposición de tres días, y un incremento de 12.7 por ciento en las consultas por infecciones de las vías respiratorias inferiores cuando se consideró un retraso de cuatro días en la exposición en el promedio móvil máximo de ocho horas. El efecto mayor para la muestra total, al igual que para el grupo de niños de 6 a 16 años, se observó en el retraso de tres días (5.1 por ciento para un aumento de 20 ppb en un máximo de una hora). Para este grupo no se observó un efecto significativo entre los niveles ambientales de ozono y el riesgo de contraer enfermedades de las vías respiratorias inferiores. CONCLUSION: La amplitud del riesgo es de suma importancia, ya que puede representar un incremento en los costos de atención en el sistema de salud y la sociedad en general. Nuestros resultados destacan la necesidad de instrumentar acciones...

OBJECTIVE: To assess the impact of atmospheric pollutants on the respiratory health of children of different age groups in Juarez City, Chihuahua, Mexico. MATERIAL AND METHODS: Data on emergency room visits between 1997 and 2001 for respiratory diseases in children less than 17 years old were obtained from hospitals in the Juarez City belonging to the Mexican Social Security Institute (IMSS). Diseases were classified into three groups according to ICD 9th and 10th codes: a) upper respiratory diseases, b) lower respiratory diseases, and c) asthma attacks. This information was stratified by age group (<=5 years and >5 years). Daily air pollution data (ozone and PM10) and weather conditions were obtained from the Monitoring Network System in Juarez City. Statistical analysis was carried out using a Generalized Additive Model assuming a Poisson distribution. RESULTS: Ozone concentrations, but not PM10, were statistically associated with emergency room visits for respiratory diseases, mainly among children 5 years old or younger. In this group, an increase of 20 ppb 1-hr maximum for ozone was associated with an increase of 8.3 percent in the number of emergency room visits for upper respiratory diseases, with a 3-day exposure lag; and an increase of 12.7 percent in the number of emergency room visits for lower respiratory diseases when considering a 4-day exposure lag in a maximum 8-hr mobile average. The largest effect for the complete sample and for the group 6 to 16 years of age was observed for 3-day lag (5.1 percent for an increase of 20 ppb 1-hr maximum for ozone). For the 6 to16 year old group we did not find a significant effect. CONCLUSION: The wide range of risk is quite important and might represent a substantial cost for the health system as well as for the society. Our results emphasize the need to implement preventive and control measures for air pollution and avoid the worsening of the present situation.

Risk factors for asthma in school children from Ciudad Juarez, Chihuahua.

Asthma and allergic rhinitis were analyzed in a random sample of school children (n=6174) residing in Ciudad Juarez, Chihuahua, Mexico. The International Study of Asthma and Allergies in Childhood methodology was applied through a standardized questionnaire. The sample was obtained with a bietapic design. Cumulative prevalence of asthma and wheezing was 6.8% (95% CI 6.2, 7.4) and 20% (95% of CI 19.7, 21.8) respectively; the prevalence of rhinitis was 5.0% (95% CI 4.5, 5.6). Family history of asthma odds ratio (OR) 2.33 (95% CI 1.78-3.05), respiratory infection after birth (OR) 3.44 (95% CI 2.76-4.29), and exposure to environmental tobacco (OR) 1.35 (95% CI 1.06-1.68) were the strongest risk factors for asthma and allergic rhinitis. The multifactorial etiology of asthma and allergic rhinitis was confirmed, as well as the importance of early exposure to environmental factors.

Prevalencia de asma y otras enfermedades alérgicas en niños escolares de Ciudad Juárez, Chihuahua / Prevalence of asthma and other allergic diseases in school children in Ciudad Juarez, Chihuahua

Objetivo. Determinar la prevalencia y severidad del asma, de la rinitis y del eczema en escolares. Material y métodos. Estudio transversal efectuado entre abril de 1998 y mayo de 1999 en Ciudad Juárez, Chihuahua, México, a una muestra aleatoria de 6 174 niños de 53 escuelas. Se aplicó la metodología propuesta por el International Study of Asthma and Allergies in Childhood (ISAAC) (etapas 1 y 2) para determinar la prevalencia y severidad del asma, rinitis y eczema. La información de prevalencia, tanto actual como acumulada para dichos padecimientos, se obtuvo mediante un cuestionario ya estandarizado y contestado por los padres de los niños. El diseño de la muestra se hizo por un muestreo mixto, en el cual se estratificó por nivel de contaminación ambiental. Se estimaron prevalencias actual y acumulada estratificando por grupo de edad, sexo, área e historia familiar de asma. Resultados. La prevalencia acumulada de asma por diagnóstico médico y sibilancia (silbidos) fue de 6.8 por ciento (IC95 por ciento 6.2-7.4) y 20. por ciento (IC95 por ciento 19.7-21.8), respectivamente; la prevalencia de sibilancia en los últimos 12 meses fue mayor en el grupo de 6-8 años que en el de 11-14 años(9.7 por ciento) contra 5.8 por ciento (p<0.01). La prevalencia de rinitis por diagnóstico médico fue de 5.0 por ciento (IC95 por ciento 4.5-5.6). La prevalencia de eczema por diagnóstico médico fue de 4.9 por ciento (IC95 por ciento 4.3-5.4). La prevalencia de síntomas de eczema en los últimos 12 meses fue de 12.7 por ciento en el grupo de 6-8 años y de 13.3 por ciento en el de 11-14 años. Los síntomas severos de asma fueron significativa-mente más prevalentes en el grupo de 6-8 años y en los meses de otoño. Conclusiones. La prevalencia de asma, tanto por diagnóstico médico como por síntomas, resulta relativamente baja en relación con otros estudios realizados con la misma metodología, pero las prevalencias de rinitis y eczema fueron altas. El texto completo en inglés de este artículo está disponible en: http://www.insp.mx/salud/index.html