Have the prevalence of eczema symptoms increased in the Mexican pediatric population? Prevalence and associated factors according to Global Asthma Network Phase I.

Background: In children, atopic dermatitis or eczema is the most common inflammatory disease of the skin. According to the International Study of Asthma and Allergies in Childhood (ISAAC) Phase IIIB in Mexico, 5.8% of children and 4.9% of adolescents had eczema symptoms. In 2012, Global Asthma Network (GAN) was established to update the prevalence of eczema and estimate potential factors contributing to its development. Objective: To estimate the prevalence and associated factors for atopic eczema symptoms and diagnosis in children and adolescents according to GAN Phase I and compare the results with ISAAC Phase IIIB in Mexico. Methods: A cross-sectional, multicenter survey was conducted in 15 Mexican centers during the period of 2015-2017 using the GAN Phase I questionnaires in children (6-7-year-olds) and adolescents (13-14-year-olds). The prevalences obtained from the GAN Phase I study, were compared with ISAAC Phase IIIB results; a Spearman's correlation analysis was conducted between temperature, relative humidity, and altitude and eczema symptoms, and a logistic regression was performed to predict current eczema symptoms by age group. Results: A total of 35 777 children and 41 399 adolescents were included. Since ISAAC Phase IIIB, the prevalence of itchy rash in the past 12 months significantly increased in the children's group [6.6% (95% CI 5.7-7.4) vs 7.8 (95% CI 7.5-8.1), p = 0.000] and adolescents' group [5.8% (95% CI 5.0-6.7) vs 6.7% (95% CI 6.5-7.0), p = 0.000].In the adolescents' group, the prevalence of nocturnal awakenings caused by rash symptoms on more than one night per week had a negative correlation between altitude (Spearman's Rho = -0.558, p value = 0.031), and a positive correlation with the average annual temperature (Spearman's Rho = 0.604, p value = 0.017) and annual relative humidity (Spearman's Rho = 0.742, p value = 0.002). The most significant associations in children were the presence of sneezing or runny or blocked nose in the past 12 months [(OR 3.13, 95% CI 2.60-3.77), p = 0.000], the use of paracetamol in the first year of life ([OR 1.52, 95% CI 1.15-2.01), p = 0.003] and the use of antibiotics in the first year of life [(OR 1.30, 95% CI 1.08-1.55) p = 0.004]. Moreover, altitude at 100-1000 m above sea level was associated with current eczema symptoms in adolescents (p = 0.001). Conclusions: There has been a significant increase in eczema symptoms in both age groups since ISAAC Phase IIIB study. Additionally, eczema symptoms were associated with temperature, relative humidity, asthma, hay fever symptoms, the use of paracetamol and antibiotics.

Global Asthma Network Phase I study in Mexico: prevalence of asthma symptoms, risk factors and altitude associations-a cross-sectional study.

BACKGROUND: Global Asthma Network (GAN) was established in 2012 as a development to the International Study of Asthma and Allergies in Childhood to improve asthma care globally. OBJECTIVE: To survey asthma, allergic rhinitis and atopic dermatitis in primary and secondary school children and to investigate and evaluate its prevalence, severity, management and risk factors in Mexico. 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 parents of 6-7-year-old primary school pupils (school children) and by 13-14-year-old adolescents. RESULTS: A total of 35 780 school children and 41 399 adolescents participated. Wheezing ever prevalence was 26.2% (95% CI 25.8% to 26.7%) in school children and 23.9% (95% CI 23.4% to 24.3%) in adolescents. The corresponding frequencies for current wheeze were 10.2% (95% CI 9.9% to 10.5%) and 11.6% (95% CI 11.2% to 11.9%). In school children, the risk factors for current wheeze were rhinitis (OR 4.484; 95% CI 3.915% to 5.134%) and rash symptoms (OR 1.735; 95% CI 1.461% to 2.059%). For adolescents, rhinitis symptoms (OR 3.492; 95% CI 3.188% to 3.825%) and allergic rhinitis diagnosis (OR 2.144; 95% CI 1.787% to 2.572%) were the most significant. For both groups, there was a negative relation with centres' sea level altitude higher than 1500 m above mean sea level (p<0.005). CONCLUSIONS: The most important risk factors for asthma symptoms in both age groups were the presence of rhinitis and rash symptoms or diagnosis. On the other hand, sea level altitude higher than 1500 metres was a protective factor.

Factors associated with allergic rhinitis in children and adolescents from northern Mexico: International Study of Asthma and Allergies in Childhood Phase IIIB.

The epidemiology of allergic diseases has not been studied extensively in Mexico. The present study, based on the International Study of Asthma and Allergies in Childhood Phase IIIB survey, reports the prevalence of allergic rhinitis and the associated risk factors in the pediatric population in four cities in northern Mexico. Children (6-7 years old) and adolescents (13-14 years old) in public elementary and secondary schools were surveyed in 2002 and 2003. The subjects were chosen randomly from Ciudad Victoria, Mexicali, Monterrey, and Tijuana. The following categories were analyzed: occurrence of rhinitis symptoms (currently or in the last 12 months), rhinoconjunctivitis symptoms, a previous diagnosis of allergic rhinitis, and relevant environmental factors. Factors associated with rhinitis that were identified previously with the chi-squared test were analyzed using logistic regression. The number of valid questionnaires was 10,892 for schoolchildren and 12,299 for adolescents. In 6- to 7-year-old children, the following frequencies were determined: rhinitis (ever), 27.9%; current rhinitis, 24.2%; rhinoconjunctivitis, 9.2%; and diagnosis of allergic rhinitis, 5.5%. The corresponding frequencies in 13- to 14-year-old children were 33.3, 34.1, 18.4, and 3.8%. In both 6- to 7-year-old and 13- to 14-year-old children, all rhinitis items were associated with asthma symptoms, dermatitis symptoms, paracetamol consumption, and maternal smoking (odds ratio, >1; p < 0.05). The main risk factors associated with allergic rhinitis symptoms in children and adolescents from cities in northern Mexico were other allergic conditions, paracetamol consumption, and passive smoking.