Obesity and asthma are major global health concerns, particularly in industrialized nations. Obesity has been shown to have detrimental effects on the respiratory system and lung function owing to metabolic issues and immunological consequences. Research has indicated that obese patients with asthma (atopic or T2-high and non-atopic or T2-low) have diminished lung function in terms of functional residual capacity (FRC), residual volume (RV), expiratory reserve volume (ERV), the FEV1/FVC ratio, and FEF 25–75% due to mechanical fat loading on the diaphragm and central adiposity when compared to non-obese asthmatic patients. Therefore, it is plausible that changes in lung function are the result of a combination of mechanical (fat loading on the diaphragm, central adiposity, bronchial hyper-reactivity, and an increase in cholinergic tone), environmental (diet and exercise), and inflammatory factors (local and systemic), which can lead to the obesity-related asthma phenotype characterized by severe asthma symptoms, poor response to corticosteroid treatment, loss of lung function, and poor quality of life from an early age.

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.

Asthma is one of the most common chronic non-communicable diseases worldwide, characterized by variable airflow limitation secondary to airway narrowing, airway wall thickening, and increased mucus resulting from chronic inflammation and airway remodeling. Current epidemiological studies reported that hypovitaminosis D is frequent in patients with asthma and is associated with worsening the disease and that supplementation with vitamin D₃ improves asthma symptoms. However, despite several advances in the field, the molecular mechanisms of asthma have yet to be comprehensively understood. MicroRNAs play an important role in controlling several biological processes and their deregulation is implicated in diverse diseases, including asthma. Evidence supports that the dysregulation of miR-21, miR-27b, miR-145, miR-146a, and miR-155 leads to disbalance of Th1/Th2 cells, inflammation, and airway remodeling, resulting in exacerbation of asthma. This review addresses how these molecular mechanisms explain the development of asthma and its exacerbation and how vitamin D₃ may modulate these microRNAs to improve asthma symptoms.

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.

Background/Objectives: Pubertal maturation encompasses hormonal, somatic, and metabolic alterations that may influence pulmonary function in children with asthma. We evaluated the correlates of pulmonary function in pediatric asthma using sex-stratified analyses of pubertal stage, BMI z-score, asthma control (ACQ-6), and HDL cholesterol levels on FEV1, FVC, and the FEV1/FVC ratio (% predicted, NHANES III). Methods: A cross-sectional study was conducted with 118 children and adolescents with asthma (74 males and 44 females). The Tanner stages were categorized as pre-/early (I–II), mid (III), and late (IV). No participant had reached Tanner stage V at recruitment, and the reference category was composed predominantly of Tanner II participants; therefore, the pubertal contrast reflected early- versus mid-/late-pubertal physiology rather than a strictly prepubertal-versus-pubertal comparison. We performed hierarchical linear regression with bias-corrected and accelerated bootstrap inference (5000 replicates) for each sex and for all participants combined, complemented by a formal sex × predictor interaction test. Results: Mid- and late puberty were independently associated with reduced FEV1% and FVC% (β −0.25 to −0.31), without affecting the FEV1/FVC ratio. Sex-stratified analyses were exploratory and identified apparently divergent predictor sets by sex: in males, the pubertal stage was significant in FEV1% and FVC% (β −0.30 to −0.42), whereas the BMI z-score diminished the FEV1/FVC ratio (β = −0.274). In females, FEV1% was associated with HDL-c (β = 0.463), BMI z-score (β = 0.429), and ACQ-6 score (β = −0.306); the female FEV1/FVC% model showed a substantial apparent effect (Cohen’s f² = 0.508), with ACQ-6 score and HDL-c as primary associated variables. The formal sex × predictor interaction test in the combined sample, however, did not reach statistical significance (ΔR² = 0.037; p = 0.178), indicating that the sex-differential patterns observed in the stratified models were not confirmed as effect modifications. Conclusions: Sex-stratified exploratory analyses in this pediatric asthma cohort identified apparently divergent patterns of associations in males and females; however, the formal interaction test was not statistically significant, indicating that these stratified differences were not confirmed and require validation in adequately powered prospective cohorts. These findings identify HDL-c, body composition, and symptom control as candidate correlates of pulmonary function, with potential sex-related differences warranting further investigation.

Background/Objective: Obesity has been linked to a distinct non-allergic, late-onset, neutrophilic asthma phenotype for more than two decades, yet whether obesity should be regarded as a cause of that phenotype rather than a coexisting comorbidity remains unresolved because randomised allocation to obesity is neither feasible nor ethical. This review asks whether the evidence accumulated between 1995 and 2026 supports a causal interpretation. Methods: A structured narrative synthesis was undertaken. PubMed/MEDLINE, Scopus and Web of Science were searched from January 1995 to June 2026 (the synthesis emphasises the 2020–2026 evidence while drawing on the full window for landmark studies) for cohort, cross-sectional, Mendelian randomisation (MR), interventional, mechanistic and pharmaco-epidemiological studies; landmark earlier work was retained where it remains the primary source for a given viewpoint. The retrieved evidence was mapped onto Sir Austin Bradford Hill’s nine viewpoints (1965) and triangulated using E-values for unmeasured confounding, GRADE, directed acyclic graphs and MR. Results: All nine viewpoints were satisfied to varying degrees. Strength: effect estimates 1.4–6.8, E-values 4.8–13.1, MR summary risk ratio 1.05 per 1 kg/m². Consistency: replication across four continents, both sexes and multiple study designs. Temporality: prospective cohort and life-course MR evidence. Biological gradient: body mass index dose–response for TNFα, IL-17A and Th17 frequency. Plausibility: a twelve-layer architecture from adipose dysfunction to bronchial epithelium. Coherence, experimental evidence (bariatric surgery, lifestyle weight loss, GLP-1 receptor agonists, murine and in vitro models) and analogy were also supported; specificity was met at the phenotype level. Conclusions: The cumulative evidence strongly supports a causal contribution of obesity to the development of the late-onset, non-allergic asthma phenotype while falling short of definitive proof (GRADE: moderate certainty), with implications for primary prevention, endotype-targeted therapy and longitudinal research. Phenotype-stratified MR remains the principal missing element of the causal argument.