Low prevalence of asthma in Mexican children and adults with a positive rtRT-PCR test for SARS-CoV-2: a cross-sectional study during the 2020 pandemic.

BACKGROUND: It has recently been argued that asthma does not increase the risk of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection. If so, the prevalence of asthma in subjects diagnosed with COVID-19 should be lower than in the general population. OBJECTIVE: To determine the prevalence of asthma in Mexican children and adults with SARS-CoV-2 infection. METHODS: A public database of the Epidemiological Surveillance System for Viral Respiratory Disease in Mexico was analyzed. Those who underwent the real-time reverse transcriptase-polymerase chain reaction-SARS-CoV-2 (rtRT-PCR-SARS-CoV-2) test from February 27 to June 21, 2020, were included. In addition to the prevalence of asthma, some factors associated with it were investigated. RESULTS: Data from 417,366 subjects were analyzed. Asthma prevalence in children, adults, and global were 3.7%, 3.3%, and 3.3%, respectively. Although the asthma prevalence was lower in SARS-CoV-2 positive over negative patients, significant differences were only found in adults (2.8% vs. 3.7% respectively; odds ratio (OR) = 0.74; 95% confidence interval (CI): 0.71-0.77); but not in children (3.5% vs. 3.8%, respectively; OR = 0.91; 95%CI: 0.76-1.10). Multivariate analysis showed in younger than 18 years that girls and immunosuppression were factors associated with a decrease in the odds to develop asthma. In adults, asthma was positively associated with females, obesity, smoking, immunosuppression, chronic obstructive pulmonary disease, arterial hypertension, and cardiovascular disease. CONCLUSION: The prevalence of asthma in child and adult were lower than those previously reported. Our study seems to support the hypothesis that asthma patients have a lower risk of SARS-CoV-2 infection. Further studies are required to demonstrate the consistency of our findings.

Red Meat Hypersensitivity and Probable Alpha-Gal Syndrome: Prevalence Among Adolescents.

INTRODUCTION: It is unknown whether late adolescents represent a particular risk group for the development of red meat hypersensitivity (RMH) and alpha-gal syndrome (AGS). This age group's physiological changes and eating habits could play a determining role. This study aimed to estimate the self-reported prevalence of RMH and probable AGS among late adolescents. METHODS: A cross-sectional study analyzed a sample of 1992 Mexican adolescents between 15 and 18 years of age. The data were obtained with a previously validated questionnaire that asked about the clinical manifestations related to red meat intake. Confidence intervals at 95% (95% CI) were estimated for proportions. RESULTS: In total, there were 19 adolescents with RMH, a prevalence of 1.0% (95% CI: 0.6-1.5%). The main red meats related to symptoms were pork (89.5%), beef (21.1%), lamb (10.5%), and mutton (5.1%). The most frequent manifestations of RMH were gastrointestinal (73.7%), respiratory (63.2%), and cutaneous (63.2%). Once the symptoms were grouped, there were two cases of urticaria (2/19, 10.5%) and six cases with probable anaphylaxis (6/19, 31.6%). Finally, three adolescents were considered probable cases of AGS, which represents a prevalence of 0.15% (95% CI: 0.1-0.4%). CONCLUSION: Although the prevalence of RMH in late adolescents is low, early detection is justified because approximately one-third present with severe symptoms.

[Prevalence of cow´s milk allergy and lactose intolerance among Mexican late adolescents]. / Prevalencia de alergia a la leche de vaca e intolerancia a la lactosa en adolescentes tardíos mexicanos.

OBJECTIVE: To determine the prevalence of cow´s milk allergy and lactose intolerance in a sample of late adolescents. METHODS: Through a population-based study, data corresponding to students with aged 15 to 18 years were analyzed. RESULTS: A total of 1992 adolescents was analized. The prevalence of cow´s milk allergy was 1.4% (95% CI: 0.2% to 0.8%) and the prevalence of lactose intolerance was 0.5% (95% CI: 0.2% to 0.8%). Adolescents with cow´s milk allergy had fewer gastrointestinal symptoms (p = 0.036), but more skin (p < 0.001) and respiratory (p = 0.028) ailments than adolescents with lactose intolerance. CONCLUSIONS: The manifestations associated with cow's milk consumption in late adolescents seem to correspond mainly to cow´s milk allergy than to lactose intolerance.

OBJECTIVO: Determinar la prevalencia de alergia a la proteína de la leche de vaca e intolerancia a la lactosa en una muestra de adolescentes tardíos. MÉTODOS: Estudio transversal con base poblacional, en el que se analizaron los datos de pacientes adolescentes de 15 a 18 años. RESULTADOS: Se registraron 1992 estudiantes. La prevalencia de alergia a la proteína de la leche de vaca fue de 1.4% (IC95%: 0.9% a 2.0%) y de intolerancia a la lactosa de 0.5% (IC95%: 0.2% a 0.8%). Los adolescentes con alergia a la proteína de la leche de vaca tuvieron menos síntomas gastrointestinales (p = 0.036), pero más molestias cutáneas (p < 0.001) y respiratorias (p = 0.028) que los adolescentes con intolerancia a la lactosa. CONCLUSIONES: Las manifestaciones asociadas con el consumo de leche de vaca en adolescentes tardíos corresponden, principalmente, a la alergia de la proteína de la leche de vaca que a la intolerancia a la lactosa.

[Geographical variation of asthma prevalence among Mexican children during the COVID-19 pandemic]. / Variación geográfica en la prevalencia de asma en niños mexicanos durante la pandemia de la COVID-19.

OBJECTIVE: The purpose of this study was to analyze the geographic variation in the prevalence of asthma in children, according to their place of residence in Mexico. METHODS: A cross-sectional analysis of the epidemiological surveillance system dataset for respiratory diseases in Mexico carried on. From 27 February to 5 November 2020, a total of 1,048,576 subjects were screened for SARS-CoV2 infection, of which 35,899 were children under 18 years of age. The strength of the association was estimated by odds ratio (OR). RESULTS: Of 1,048,576 patients who attended for SARS-CoV2 infection detection, 35,899 corresponded to pediatric patients who met the study criteria. The estimated national prevalence of asthma was 3.9% (95% CI: 3.7-4.1%). The nationwide prevalence of asthma was 3.9% (95% CI: 3.7% - 4.1%); the minimum was 2.8% (Southeast region) and the maximum 6.8% (Southeast region). Compared to the South-West Region that presented the minimum prevalence at the national level, the Northwest (OR = 2.41) and Southeast (OR = 1.33) regions showed the highest risk of asthma in pediatric population. CONCLUSIONS: The prevalence of asthma in children differed markedly among the different regions of Mexico; two regions, Northwest and Southeast, stood out. This study puts into context the role of the environment on the prevalence of asthma in children.

OBJECTIVO: Estimar la prevalencia de asma en pacientes pediátricos, según su lugar de residencia en la República Mexicana, durante la pandemia por SARS-CoV-2. MÉTODOS: Estudio transversal, llevado a cabo a partir de la revisión de datos del Sistema de Vigilancia Epidemiológica para Enfermedades Respiratorias en México, analizados del 27 febrero al 5 de noviembre de 2020. Criterios de inclusión: pacientes que acudieron a la detección de infección por SARS-CoV2, menores de 18 años. La fuerza de asociación se estimó con la razón de momios. RESULTADOS: De 1,048,576 pacientes que acudieron a la detección de infección de SARS-CoV2, 35,899 correspondieron a pacientes pediátricos que cumplieron con los criterios del estudio. La prevalencia nacional de asma estimada fue de 3.9% (IC95%: 3.7-4.1%); la prevalencia mínima se observó en la región Suroeste (2.8%) y la máxima en el Sureste (6.8%); comparada con la región Suroeste, que registró la prevalencia mínima a nivel nacional, y la Noroeste (RM = 2.41) y Sureste (RM = 1.33) mostraron el mayor riesgo de asma en la población pediátrica. CONCLUSIONES: La prevalencia de asma en niños mexicanos difirió notoriamente en los diferentes estados de la República Mexicana; sobresalieron las regiones Noroeste y Sureste. Este estudio pone de manifiesto el papel del medio ambiente en la prevalencia del asma en pacientes pediátricos mexicanos.

Prevalence of allergic diseases and their symptoms in schoolchildren according to the birth mode.

BACKGROUND: The relationship between birth by cesarean section (CS) and allergic diseases' prevalence continues to be controversial. We aimed to investigate if being born by CS is associated with the prevalence of allergic diseases and their symptoms in schoolchildren. METHODS: This study included children between 6 and 7 years of age, selected by population-based sampling. We investigated the presence of allergic diseases and their symptoms, family history of asthma, smoking in parents, breastfeeding, exposure to pets, the season of birth, number of siblings, consumption of unpasteurized cow's milk, and mode of birth. RESULTS: We included 1003 subjects (526 girls), of which 44.2% were born through CS. The prevalence of allergic diseases did not differ according to birth mode. Asthma in either parent, current smoking by the mother, breastfeeding, and unpasteurized cow's milk consumption were associated with wheezing at some time in life. CONCLUSIONS: No association between CS birth mode and allergic diseases and their symptoms was found.

[Association of comorbidities and symptomatic infection and multisystemic inflammatory syndrome due to SARS-CoV-2 in children]. / Asociación de comorbilidades con infección sintomática y síndrome inflamatorio multisistémico por SARS-CoV-2 en niños.

BACKGROUND: In children, infection by the new coronavirus (SARS-CoV-2) usually occurs asymptomatic or with mild clinical data, only a minor proportion have severe symptoms or a set of post-infectious signs and symptoms described as Pediatric Inflammatory Multisystemic Syndrome (PIMS). AIM: To describe the association of comorbidities with symptomatic infection and PIMS due to SARS-CoV-2 in children. METHODS: Analytical cross-sectional study, pediatric patients hospitalized were included. Active infection was diagnosed by polymerase chain reaction and/or antigenic tests. Patients with PIMS were identified by the definition proposed by the World Health Organization. RESULTS: 375 patients were studied, the median age was 3.8 years. 47.7% (n: 179) had comorbidities, the most frequent were: solid neoplasms and/or hematological diseases 17.1% (n: 64), obesity 13.3% (n: 48) and chronic pneumopathies 9, 3% (n: 35). SARS-CoV-2 infection was present in 16.5% (n: 62/375) and PIMS in 10.4% (n. 39/375). Children with obesity showed a higher risk of infection (OR 2.21, 95% CI 1.05-4.6) and in those with cancer (OR 0.15, 95% CI 0.03-0.68) the PIMS risk was lower. CONCLUSIONS: The presence of comorbidities modifies the risk of infection by SARS-CoV-2 and PIMS.

Neutralizing Antibodies Titers and Side Effects in Response to BNT162b2 Vaccine in Healthcare Workers with and without Prior SARS-CoV-2 Infection.

The main expected result of a vaccine against viruses is the ability to produce neutralizing antibodies. Currently, several vaccines against SARS-CoV-2 are being applied to prevent mortal complications, being Pfizer-BioNTech (BNT162b2) one of the first to be authorized in the USA and Mexico (11 December 2020). This study evaluated the efficacy of this vaccine on antibody production with neutralizing capacity and its side effects in healthcare workers with and without prior SARS-CoV-2 infection and in a group of unvaccinated individuals with prior COVID-19. The main findings are the production of 100% neutralizing antibodies in both groups after the second dose, well-tolerated adverse effects, the possible presence of immunosenescence, and finally, we support that a single dose of this vaccine in individuals with prior COVID-19 would be sufficient to achieve an immunization comparable to people without prior COVID-19 with a complete vaccination program (2 doses).

[The prevalence of oral allergy syndrome: regarding a new classification]. / Prevalencia del síndrome de alergia oral: a propósito de una nueva clasificación.

BACKGROUND: Recently, the oral allergy syndrome (OAS) has been classified according to the foods that induce it: phenotype I, when it is caused only by plant-derived foods; phenotype II, when it is caused by foods of both animal and plant origin. OBJECTIVE: To determine the prevalence of OAS in late teenagers according to the new classification. METHODS: A cross-sectional study in which data from 1,992 teenagers, aged 15-18 year-old, was analyzed; the information was obtained through a structured questionnaire, where questions were asked about oral symptoms according to the type of food that had been ingested. RESULTS: The overall prevalence of OAS was of 1.7% (95% CI = 1.2-2.4); for phenotype I, it was of 0.85% and, for phenotype II, it was of 0.85%. According to the phenotype, there was no difference by sex and personal history of atopic disease; instead, the onset time of the symptoms did show an association with the phenotype (p = 0.048). The frequency of skin and mucosal symptoms and respiratory ailments differed between the groups. Regarding gastrointestinal symptoms, diarrhea was markedly more frequent in phenotype II (p = 0.044). CONCLUSION: Two phenotypes with OAS were clearly identified: the first one was associated exclusively to foods of plant origin, and the other was related to foods of both plant and animal origin.

Antecedentes: Recientemente, el síndrome de alergia oral (SAO) ha sido clasificado de acuerdo con los alimentos que lo inducen: fenotipo I, relacionado con alimentos derivados de plantas; fenotipo II, provocado por alimentos de origen vegetal y animal. Objetivo: Determinar la prevalencia del síndrome de alergia oral en adolescentes tardíos según la nueva clasificación. Métodos: Estudio transversal en el que se analizaron los datos de 1992 adolescentes de 15 a 18 años; la información se obtuvo a través de un cuestionario estructurado, en el que se interrogó acerca de síntomas orales según el tipo de alimento consumido. Resultados: La prevalencia global de síndrome de alergia oral fue de 1.7 % (IC 95 % = 1.2-2.4): fenotipo I, 0.85 % y fenotipo II, 0.85 %. Según el fenotipo no hubo diferencia por sexo e historia personal de enfermedad atópica; el tiempo de inicio de los síntomas sí mostró asociación (p = 0.048). La frecuencia de los síntomas respiratorios, en piel y mucosas no difirieron entre los grupos; respecto a los síntomas gastrointestinales, la diarrea fue notoriamente más frecuente en el fenotipo II (p = 0.044). Conclusión: Se identificaron claramente los dos fenotipos del síndrome de alergia oral: uno asociado con alimentos de origen vegetal y otro a alimentos tanto de origen vegetal como animal.

[The prevalence of allergic rhinitis and atopic dermatitis in late adolescents differs according to their gender]. / La prevalencia de rinitis alérgica y dermatitis atópica en adolescentes tardíos difiere de acuerdo con el sexo.

BACKGROUND: In Mexico, there are very few studies aimed at establishing the prevalence of allergic rhinitis (AR) and atopic dermatitis (AD) in late adolescents. OBJECTIVE: To determine the prevalence of allergic rhinitis and atopic dermatitis in late adolescents and compare it according to their gender. METHODS: A cross-sectional study that included 1992 15 to 18 year old adolescents who were recruited through a stratified and randomized probabilistic sample by clusters. The prevalence of AR (allergic rhinitis) and AD (atopic dermatitis) was identified with the questionnaire of "The International Study of Asthma and Allergies in Childhood". RESULTS: 1056 (53%) women and 936 (47%) men were included in the study. The prevalence of AR was 9.0% (95% CI = 7.8% - 10.4%); the frequency was higher in women (6.7% versus 11.1%, p = 0.001). The symptoms of rhinitis plus conjunctivitis predominated in women (16.0% versus 23.1%, p < 0.0001). The prevalence of AD was 5.2% (95% CI = 4.3% - 6.2%) and, once again, it was more frequent in women (7.7% versus 2.4%, p < 0.0001). The main factors associated with AR and AD were the female gender and a history of family atopic allergic diseases (p < 0.001). CONCLUSIONS: There was a significant difference in the prevalence of AR and AD according to gender in late adolescents; women were most affected. In addition, a history of family atopic allergic diseases was another risk factor that was linked to both diseases.

Antecedentes: En México son escasos los estudios encaminados a establecer la prevalencia de la rinitis alérgica y la dermatitis atópica en adolescentes tardíos. Objetivo: Determinar la prevalencia de rinitis alérgica y dermatitis atópica en adolescentes tardíos y compararla conforme el sexo. Métodos: Estudio transversal de 1992 adolescentes de 15 a 18 años, reclutados mediante muestreo probabilístico por conglomerados, estratificado y aleatorizado. Las prevalencias de rinitis alérgica y dermatitis atópica se identificaron con el cuestionario propuesto en The Internacional Study of Asthma and Allergies in Childhood. Resultados: Se incluyeron 1056 mujeres (53 %) y 936 hombres (47 %). La prevalencia de rinitis alérgica fue de 9.0 % (IC 95 % = 7.8-10.4); la frecuencia fue mayor en las mujeres (6.7 % versus 11.1 %, p = 0.001). Los síntomas de rinitis más conjuntivitis predominaron en las mujeres (16.0 % versus 23.1 %, p < 0.0001). La prevalencia de dermatitis atópica fue de 5.2 % (IC 95 % = 4.3-6.2); fue más frecuente en las mujeres (7.7 % versus 2.4 %, p < 0.0001). Los principales factores asociados con rinitis alérgica y dermatitis atópica fueron sexo femenino y atopia familiar (p < 0.001). Conclusiones: Se registró diferencia significativa en la prevalencia de rinitis alérgica y dermatitis atópica conforme el sexo en los adolescentes tardíos; las mujeres fueron las más afectadas. La atopia familiar fue otro factor asociado.

Prevalence of allergic diseases and their symptoms in schoolchildren according to the birth mode / Prevalencia de enfermedades alérgicas y síntomas en escolares de acuerdo con la vía de nacimiento

Abstract Background: The relationship between birth by cesarean section (CS) and allergic diseases’ prevalence continues to be controversial. We aimed to investigate if being born by CS is associated with the prevalence of allergic diseases and their symptoms in schoolchildren. Methods: This study included children between 6 and 7 years of age, selected by population-based sampling. We investigated the presence of allergic diseases and their symptoms, family history of asthma, smoking in parents, breastfeeding, exposure to pets, the season of birth, number of siblings, consumption of unpasteurized cow’s milk, and mode of birth. Results: We included 1003 subjects (526 girls), of which 44.2% were born through CS. The prevalence of allergic diseases did not differ according to birth mode. Asthma in either parent, current smoking by the mother, breastfeeding, and unpasteurized cow’s milk consumption were associated with wheezing at some time in life. Conclusions: No association between CS birth mode and allergic diseases and their symptoms was found.

Resumen Introducción: La relación entre el nacimiento por operación cesárea y las enfermedades alérgicas es controversial. El objetivo del presente estudio fue investigar si el nacimiento por cesárea se asocia con la prevalencia de las enfermedades alérgicas y sus síntomas en escolares. Métodos: Estudio transversal que incluyó una muestra probabilística de niños de 6 a 7 años. Se registraron la presencia de enfermedades alérgicas y sus síntomas, la historia familiar de asma, el tabaquismo en los padres, la alimentación al seno materno, la exposición a mascotas, la estación de nacimiento, el número de hermanos, el consumo de leche no pasteurizada de vaca y la vía de nacimiento. Resultados: Se incluyeron 1003 sujetos (526 niñas), de los cuales el 44.2% nacieron por cesárea. La prevalencia de enfermedades alérgicas no difirió según la vía de nacimiento. El antecedente de asma en alguno de los progenitores, el tabaquismo actual en la madre, la lactancia materna y el consumo de leche no pasteurizada de vaca se asociaron con sibilancias presentes alguna vez en la vida. Conclusiones: No se demostró asociación entre el nacimiento por cesárea y las enfermedades alérgicas y sus síntomas.

Asociación de comorbilidades con infección sintomática y síndrome inflamatorio multisistémico por SARS-CoV-2 en niños / Association of comorbidities and symptomatic infection and multisystemic inflammatory syndrome due to SARS-CoV-2 in children

INTRODUCCIÓN: En niños, la infección por el nuevo coronavirus (SARS-CoV-2) habitualmente cursa asintomática o con síntomas leves; sólo una proporción menor presenta síntomas graves o un conjunto de signos y síntomas postinfecciosos descritos como síndrome inflamatorio multisistémico pediátrico (SIMP). OBJETIVO: Describir la asociación de comorbilidades con la infección sintomática y SIMP por SARS-CoV-2 en niños. PACIENTES Y MÉTODOS: Estudio transversal analítico, se incluyeron pacientes pediátricos hospitalizados. Mediante reacción de la polimerasa en cadena y/o pruebas antigénicas se diagnosticó la infección activa y con la definición propuesta por la Organización Mundial de la Salud se identificaron pacientes con SIMP. RESULTADOS: Se estudiaron 375 pacientes, la mediana de edad fue de 3,8 años. El 47,7% (n: 179) presentó comorbilidades, siendo las más frecuentes: neoplasias sólidas y/o enfermedades hematológicas 17,1% (n: 64), obesidad 13,3% (n: 48) y neumopatías crónicas 9,3% (n: 35). Presentaron infección por SARS-CoV-2 el 16,5% (n: 62/375) y SIMP el 10,4% (n. 39/375). Los niños con obesidad mostraron mayor riesgo de infección sintomática (OR 2,21, IC 95% 1,05-4,6) y en aquellos con cáncer (OR 0,15, IC 95% 0,03-0,68) el riesgo de SIMP fue menor. CONCLUSIONES: La presencia de comorbilidades modifica el riesgo de infección por SARS-CoV-2 y SIMP.

BACKGROUND: In children, infection by the new coronavirus (SARS-CoV-2) usually occurs asymptomatic or with mild clinical data, only a minor proportion have severe symptoms or a set of post-infectious signs and symptoms described as Pediatric Inflammatory Multisystemic Syndrome (PIMS). AIM: To describe the association of comorbidities with symptomatic infection and PIMS due to SARS-CoV-2 in children. METHODS: Analytical cross-sectional study, pediatric patients hospitalized were included. Active infection was diagnosed by polymerase chain reaction and/or antigenic tests. Patients with PIMS were identified by the definition proposed by the World Health Organization. RESULTS: 375 patients were studied, the median age was 3.8 years. 47.7% (n: 179) had comorbidities, the most frequent were: solid neoplasms and/or hematological diseases 17.1% (n: 64), obesity 13.3% (n: 48) and chronic pneumopathies 9, 3% (n: 35). SARS-CoV-2 infection was present in 16.5% (n: 62/375) and PIMS in 10.4% (n. 39/375). Children with obesity showed a higher risk of infection (OR 2.21, 95% CI 1.05-4.6) and in those with cancer (OR 0.15, 95% CI 0.03-0.68) the PIMS risk was lower. CONCLUSIONS: The presence of comorbidities modifies the risk of infection by SARS-CoV-2 and PIMS.

Low prevalence of asthma in Mexican children and adults with a positive rtRT-PCR test for SARS-CoV-2: a cross-sectional study during the 2020 pandemic

Background: It has recently been argued that asthma does not increase the risk of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection. If so, the prevalence of asthma in subjects diagnosed with COVID-19 should be lower than in the general population. Objective: To determine the prevalence of asthma in Mexican children and adults with SARS-CoV-2 infection. Methods: A public database of the Epidemiological Surveillance System for Viral Respiratory Disease in Mexico was analyzed. Those who underwent the real-time reverse transcriptase-polymerase chain reaction-SARS-CoV-2 (rtRT-PCR-SARS-CoV-2) test from February 27 to June 21, 2020, were included. In addition to the prevalence of asthma, some factors associated with it were investigated. Results: Data from 417,366 subjects were analyzed. Asthma prevalence in children, adults, and global were 3.7%, 3.3%, and 3.3%, respectively. Although the asthma prevalence was lower in SARS-CoV-2 positive over negative patients, significant differences were only found in adults (2.8% vs. 3.7% respectively; odds ratio (OR) = 0.74; 95% confidence interval (CI): 0.71–0.77); but not in children (3.5% vs. 3.8%, respectively; OR = 0.91; 95%CI: 0.76–1.10). Multivariate analysis showed in younger than 18 years that girls and immunosuppression were factors associated with a decrease in the odds to develop asthma. In adults, asthma was positively associated with females, obesity, smoking, immunosuppression, chronic obstructive pulmonary disease, arterial hypertension, and cardiovascular disease. Conclusion: The prevalence of asthma in child and adult were lower than those previously reported. Our study seems to support the hypothesis that asthma patients have a lower risk of SARS-CoV-2 infection. Further studies are required to demonstrate the consistency of our findings (AU)

Defectos del tubo neural altos y bajos al nacer en el Hospital Civil Juan I. Menchaca / Upper and lower neural tube defect at birth in the Hospital Civil Juan I. Menchaca

Objetivo: determinar la prevalencia de los Defectos del Tubo Neural (DTN) altos y bajos al nacer, y la frecuencia de exposición a gripe, anticonceptivos y analgésicos durante el primer trimestre de embarazo.Introducción: los defectos del tubo neural se encuentran asociados a factores genéticos y ambientales. Aunque ya se han identificado a varios de ellos, se hipotetiza que los defectos del tubo neural altos tienen diferente etiología de los bajos.Material y método: se realizó un estudio descriptivo transversal simple. Se incluyeron a todos los recién nacidos (RN) vivos o muertos con defectos del tubo neural, con peso mayor de 500 g y/o más de 20 semanas de gestación que nacieron entre enero de 1989 y marzo de 1997 en el Hospital Civil Dr. Juan I. Menchaca. Se consideraron para su estudio, variables demográficas, frecuencia de exposición a gripe, anticonceptivos y analgésicos así como las características del recién nacido.Resultados: de 56,926 nacimientos 166 presentaron defectos del tubo neural. La prevalencia general promedio de DTN en el hospital fue de 25 x 10,000 RN; los DTN altos tuvieron prevalencia de 18.8 x 10,000 RN, mientras que los DTN bajos fue de 10.4 x 10,000 RN.La anencefalia fue la malformación más frecuente de los DTN altos con una tasa de 14 x 10,000; y el mielomeningocele en el grupo con DTN bajos con una tasa de 6.5 x 10,000. La ingesta de acetaminofén fue tres veces mayor en el grupo con DTN alto. La presencia de gripe y uso de anticonceptivos no presentó grandes diferencias entre uno y otro grupo de malformados. El peso, talla y edad gestacional de los RN con DTN altos fueron menores y nacieron principalmente por vía vaginal; mientras que los recién nacidos con DTN bajos lo hicieron por cesárea.Discusión: se encontraron algunas diferencias entre los DTN altos y bajos, sobre todo en la frecuencia de mielocele y mielomeningocele, en la ingesta de acetaminofén y en la forma de resolución de los partos.