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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% (IC95% 6.2-7.4) y 20.% (IC95% 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%) contra 5.8% (phttp://www.insp.mx/salud/index.html

Background: Although DHA (22:6n-3) is critical for fetal development, results from randomized controlled trials (RCTs) of prenatal DHA supplementation report inconsistent effects on offspring health. Variants in fatty acid desaturase (FADS) genes that regulate the conversion of n-3 and n-6 essential fatty acids into their biologically active derivatives may explain this heterogeneity.Objectives: We investigated the effect of prenatal DHA supplementation on the offspring metabolome at age 3 mo and explored differences by maternal FADS single-nucleotide polymorphism (SNP) rs174602.Methods: Data were obtained from a double-blind RCT in Mexico [POSGRAD (Prenatal Omega-3 Fatty Acid Supplementation and Child Growth and Development)] in which women (18-35 y old) received DHA (400 mg/d) or placebo from mid-gestation until delivery. Using high-resolution MS with LC, untargeted metabolomics was performed on 112 offspring plasma samples. Discriminatory metabolic features were selected via linear regression (P < 0.05) with false discovery rate (FDR) correction (q = 0.2). Interaction by SNP rs174602 was assessed using 2-factor ANOVA. Stratified analyses were performed, where the study population was grouped into carriers (TT, TC; n = 70) and noncarriers (CC; n = 42) of the minor allele. Pathway enrichment analysis was performed with Mummichog (P < 0.05).Results: After FDR correction, there were no differences in metabolic features between infants whose mothers received prenatal DHA (n = 58) and those whose mothers received placebo (n = 54). However, we identified 343 differentially expressed features in the interaction analysis after FDR correction. DHA supplementation positively enriched amino acid and aminosugars metabolism pathways and decreased fatty acid metabolism pathways among offspring of minor allele carriers and decreased metabolites within the tricarboxylic acid cycle and galactose metabolism pathways among offspring of noncarriers.Conclusions: Our findings demonstrate differences in infant metabolism in response to prenatal DHA supplementation by maternal SNP rs174602 and further support the need to incorporate genetic analysis of FADS polymorphisms into DHA supplementation trials.This trial was registered at clinicaltrials.gov as NCT00646360. [ABSTRACT FROM AUTHOR]

Exposure to indoor allergens represents a significant risk factor for allergies and asthma in several parts of the world. In Mexico, few studies have evaluated indoor allergens, including cat, dog, and mouse allergens and the factors that predict their presence. This study evaluates the main environmental and household predictors of high prenatal allergen levels and multiple allergen exposures in a birth cohort from Mexico City. A cross-sectional study was conducted as part of a birth cohort study of 1094 infants recruited during pregnancy and followed until delivery. We collected dust samples in a subset of 264 homes and assessed environmental factors. Der p 1, Der f 1, dust mite group 2, Fel d 1, Can f 1, Rat n 1, Mus m 1, and Bla g 2 concentrations in dust samples were measured using immunoassays. To define detectable allergen levels, the lowest limits of detection for each allergen were taken as cutoff points. Overall allergen exposure was considered high when four or more allergens exceeded detectable levels in the same household. Logistic regression was used for predictive models. Eighty-five percent of homes had at least one allergen in dust over the detection limit, 52.1% had high exposure (four or more allergens above detectable limits), and 11.7% of homes had detectable levels for more than eight allergens. Der p 1, Der p 2, Mus m 1, and Fel d 1 were the most frequent allergens detected. Each allergen had both common and distinct predictors. The main predictors of a high multiple allergen index were the size of the home, pesticide use, mother's age, mother as homemaker, and season. Increased indoor environmental allergen exposure is mainly related to sociodemographic factors and household cleaning. [ABSTRACT FROM AUTHOR]

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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. [ABSTRACT FROM AUTHOR]

Objectives. To assess the prevalence of allergic rhinitis symptoms among school-children 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% Confidence Intervals (95%CI). 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% and 10.5%, 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%CI: 0.24-0.77), or nasal and ocular symptoms (OR = 0.39; 95%CI: 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. [ABSTRACT FROM AUTHOR]

Copyright of Salud Pública de México is the property of Instituto Nacional de Salud Publica and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The article focuses on a cross-sectional study that was conducted to evaluate non occupational biological exposure to 1,1,1-trichloro-2,2-bis(4-chlorophenyl)ethane (DDT) compounds and to identify the main factors associated with such exposure in a malaria endemic region in Mexico. Capillary gas column chromatography was used to determine levels of p,p'-DDT and its metabolites in plasma. The results of this study documented high p,p'-DDE and DDT levels in Mexican men from Chiapas in spite of the pesticide's severe restriction in 1987. DDT and its metabolites are stored in adipose tissue, and it has been reported that blood concentrations are influenced by blood lipid content. Thus, most literature adjusts blood organochlorine concentrations to lipid weight. Moreover, because organochlorines are stored in the adipose tissue, recent studies have reported that BMI, considered to be an important measure of obesity, is an important predictor of plasma concentrations of DDT in multivariate analyses.

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. [ABSTRACT FROM AUTHOR]