Prevalence and risk factors associated with allergic rhinitis in Mexican school children: Global Asthma Network Phase I.

BACKGROUND: The International Study of Asthma and Allergies in Childhood (ISAAC) showed a wide variability in prevalence and severity of allergic rhinitis (AR) and rhinoconjunctivitis (ARC), in addition to other atopic diseases (Asher et al, 2006).1 The Global Asthma Network (GAN) has continued to study these conditions. OBJECTIVE: To estimate the prevalence of AR and ARC in children and adolescents in Mexico and to assess their association with different risk factors. METHODS: GAN Phase I is a cross-sectional, multicentre survey carried out in 15 centres corresponding to 14 Mexican cities throughout 2016-2019 using the validated Spanish language version of the GAN Phase I questionnaires. The questionnaires were completed by 35 780 parents of 6-7 year old primary school pupils (children) and by 41 399 adolescents, 13-14 years old. RESULTS: The current and cumulative prevalence of AR was higher in the adolescents (26.2-37.5%, respectively) in comparison to the children (17.9-24.9%, respectively), especially in female participants. This tendency was also observed in the current prevalence of ARC, where 15.1% of female adolescents reported nasal symptoms accompanied with itchy-watery eyes in the past year. The most important risk factors for AR and ARC were the presence of wheezing in the past 12 months, wheezing in the first year of life, the previous diagnosis of asthma and eczema symptoms. Furthermore, allergic symptoms had a negative tendency concerning altitude. CONCLUSION: This is the largest AR epidemiological study ever conducted in Mexico. It shows an increase in AR prevalence, as well as significant associations with modifiable risk factors, which could help to establish recommendations to reduce the burden of this condition.

Have asthma symptoms in Mexico changed in the past 15 years? Time trends from the International Study of Asthma and Allergies in Childhood to the Global Asthma Network

BACKGROUND: The Global Asthma Network (GAN) builds on the International Study of Asthma and Allergies in Childhood (ISAAC). OBJECTIVE: To compare asthma prevalence time trends in primary and secondary school children in four Mexican centers participating in ISAAC and GAN. METHODS: GAN is a cross-sectional, multicenter, epidemiological methodology carried out in groups of primary school children aged 6-7 and adolescents aged 13-14 following the ISAAC Phase Three protocol, with additional questions on risk factors and asthma management. RESULTS: Overall, the prevalence of asthma symptoms and diagnosis in primary school children was higher in males than in females both in ISAAC (p < 0.05) and in GAN (p < 0.01), while adolescent females had a higher prevalence, also both in ISAAC (p < 0.001) and in GAN (p < 0.001). CONCLUSION: The prevalence of asthma and its symptoms has increased from ISAAC Phase Three since 2003 to GAN Phase I in Mexico in 2019. These findings are in line with the increases observed in the centers with low asthma baseline prevalence in ISAAC Phase One in comparison with ISAAC Phase Three

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The burden of asthma in an inner-city area: A historical review 10 years after Isaac.

BACKGROUND: According to the International Study of Asthma and Allergies in Childhood (ISAAC) methodology, in 2003, the prevalence of asthma symptoms in children 6-7 years old and adolescents 13-14 years old was 11.6% and 13.7%, respectively. Since then, the number of asthma cases has increased worldwide. The study was conducted in several districts in northern Mexico City to evaluate the prevalence of asthma in these age groups and examine possible risk factors. The data were compared to the 2003 results from the same area. METHODS: This was a comparative cross-sectional study following the official Global Asthma Network (GAN) methodology. The parents or guardians of participants completed a questionnaire that explored demographics, asthma symptoms, diagnoses, and possible risk factors. Central tendency measurements were determined for statistical analysis and chi-squared distribution for possible risk factors. RESULTS: A total of 2515 children aged 6-7 years and 3375 adolescents aged 13-14 years participated in the study. Compared to the ISAAC results, we found a greater prevalence of wheezing in both children (at some time in life, 19.2% vs. 27.1%; over the last year, 6.8% vs. 10.6%) and adolescents (at some time in life, 16.9% vs. 19.7%), and for children with an asthma diagnosis (4.5% vs. 5.1%). For both groups, the most common risk factor associated with wheezing was the presence of rhinitis symptoms. CONCLUSIONS: Asthma symptoms are highly prevalent in Mexico City, occurring in almost 20% of adolescents. Compared to a decade ago, there was a 7.9% increase in the prevalence of asthma symptoms in children. Almost half of the children and adolescents presenting with symptoms had experienced more than four episodes per year. However, less than 50% of children and adolescents with asthma symptoms had been diagnosed with this disorder, suggesting under-diagnosis.

International Study of Asthma and Allergy in Childhood Phase III (ISAAC III): The Role of Non-Response in Valencia.

A study was done about non-participation during Phase III of the International Study of Asthma and Allergy in Childhood (ISAAC III) in Valencia to determine whether the non-response rate significantly affected the results obtained in Valencia. Of the schools selected to participate in ISAAC III, 13.3% denied not to, the main reason being they were already participated in a similar study. The ISAAC III questionnaire was handed out to participating schools for the parents of 6,358 schoolchildren aged 6-7 years. Of these, 53.4% responded correctly. The remaining 46.6% were given a non-response questionnaire (NRQ), of which 4.1% completed the questionnaire correctly. The main reason why parents who received the NRQ did not participate in ISAAC III was that their children had neither asthma nor other atopic disease, so interest was null. No significant statistical differences were observed between the prevalence of asthma in the schoolchildren who participated in ISAAC III and in the non-participants who answered the NRQ. These results suggest that the ISAAC III results relating to asthma are not biased by non-response.

Climate and prevalence of atopic eczema in 6- to 7-year-old school children in Spain. ISAAC phase III.

Atopic eczema (AE) is a chronic skin disease. Recent reports indicate that the worldwide prevalence of AE is increasing and that various environmental factors are implicated in its aetiology. Climatic conditions have been related with AE prevalence, and Spain has varying climatic conditions. The aim of this study is to document the possible climatic influence on the prevalence of AE in schoolchildren aged 6-7 years in three different climatic regions in Spain. We conducted a cross-sectional population-based survey of 28,394 schoolchildren aged 6-7 years from 10 Spanish centres in three different climatic regions. The mean participation rate was 76.5%. AE prevalence was assessed using the International Study of Asthma and Allergies in Childhood (ISAAC) questionnaire and the Spanish Academy of Dermatology criteria used in Spain to diagnose AE. The data, including annual temperature, precipitation, relative humidity and the annual number of sunny hours per climatic region, were obtained from the Spanish National Institute of Meteorology. Different AE prevalences were found in all three climatic regions studied: Atlantic, 32.9; Mediterranean 28.3; and Continental 31.2 per 100 children studied (p < 0.005). AE was positively associated with precipitation and humidity, and was negatively associated with temperature and the number of sunny hours. The results show that AE is significantly dependent on meteorological conditions.

[Prevalence of atopic eczema and nutritional factors in 6-7 year old children]. / Prevalencia de dermatitis atópica y factores nutricionales en niños de 6-7 años.

OBJECTIVES: To describe the prevalence of atopic eczema (AE) and to find the characteristics of the diet of children with AE. DESIGN: Descriptive, transversal study. SETTING: Primary schools. MAIN MEASUREMENTS: The study used the standardized and validated questionnaire of the ISAAC phase III study, which finds the prevalence of AE in children and enables inter-centre comparison to be conducted. A questionnaire about food consumption was included. The prevalence ratio (PR) of AE and food consumption (95% confidence intervals) was calculated. RESULTS: A total of 28 448 children aged 6-7 were included in the study. The prevalence of clinically diagnosed AE was 15.35% in boys and 15.24% in girls. The foods most often consumed were: dairy and cereals, followed by rice, pasta, and eggs. The least consumed were: butter, margarine, and fast food. The PR for children who consumed pasta was (PR=1.35), seafood (PR=1.28), cereals (PR=1.26), eggs (PR=1.13), and meat (PR=1.09). CONCLUSIONS: The prevalence of AE in Spain was 15.3%, and was associated with food consumption. The consumption of dairy products, cereals, and olive oil was appropriate. The intake of fruit, vegetables, seafood, and legumes was below the recommended amounts. Future studies on the question are needed.

Prevalencia de dermatitis atópica y factores nutricionales en niños de 6-7 años / Prevalence of atopic eczema and nutritional factors in 6-7 year old children

Objetivo. Describir la prevalencia de dermatitis atópica (DA) y conocer las características de la dieta en niños con DA. Diseño. Estudio descriptivo, transversal. Emplazamiento. Centros escolares de educación primaria. Mediciones principales. Se realizó un estudio mediante la utilización del cuestionario validado y estandarizado del estudio ISAAC de fase III, que permite conocer la prevalencia de DA en niños y compararla entre centros. Se acompañó de una encuesta sobre consumo de alimentos. Se calcularon la razón de prevalencia (RP) de DA en relación con el consumo de alimentos y los intervalos de confianza del 95%. Resultados. Se incluyó en el estudio a un total de 28.448 niños de 6-7 años. La prevalencia de DA clínicamente diagnosticada fue del 15,35% en niños y del 15,24% en niñas. Los alimentos más consumidos fueron la leche y los cereales, seguidos del arroz, la pasta y los huevos. Los alimentos menos consumidos fueron la mantequilla, la margarina y la comida rápida. Se observó una razón de prevalencia de DA en los niños que consumían pasta (RP = 1,35), pescado (RP = 1,28), cereales (RP = 1,26), huevos (RP = 1,13) y carne (RP = 1,09). Conclusiones. La prevalencia de DA en España fue del 15,3% asociada con el consumo de alimentos. El consumo de lácteos, cereales y aceite de oliva es adecuado. La ingesta de fruta, verdura, pescado y legumbres es inferior a la aconsejada. Sería necesario realizar futuros estudios sobre el tema

Objectives. To describe the prevalence of atopic eczema (AE) and to find the characteristics of the diet of children with AE. Design. Descriptive, transversal study. Setting. Primary schools. Main measurements. The study used the standardized and validated questionnaire of the ISAAC phase III study, which finds the prevalence of AE in children and enables inter-centre comparison to be conducted. A questionnaire about food consumption was included. The prevalence ratio (PR) of AE and food consumption (95% confidence intervals) was calculated. Results. A total of 28 448 children aged 6-7 were included in the study. The prevalence of clinically diagnosed AE was 15.35% in boys and 15.24% in girls. The foods most often consumed were: dairy and cereals, followed by rice, pasta, and eggs. The least consumed were: butter, margarine, and fast food. The PR for children who consumed pasta was (PR=1.35), seafood (PR=1.28), cereals (PR=1.26), eggs (PR=1.13), and meat (PR=1.09). Conclusions. The prevalence of AE in Spain was 15.3%, and was associated with food consumption. The consumption of dairy products, cereals, and olive oil was appropriate. The intake of fruit, vegetables, seafood, and legumes was below the recommended amounts. Future studies on the question are needed