insights

Risk Factors: Pediatric & Adult-Onset Asthma

In adults, chronic rhinosinusitis with nasal polyps and severe respiratory infections such as pneumonia as a child have been identified as risk factors for the development of severe adult-onset asthma, according to a 2021 Finnish population study.⁵ Early-life covariates that also increased risk included growing up in environments where exposure to biologic allergens was more frequent and having parental history of asthma, allergy, and smoking.⁵ In children, asthma may be associated with allergic responses and the atopic march.⁶ In addition, environmental pollutant exposure may play a role in pediatric asthma risk. A study published in 2019 of 714 Parisian children as part of an ongoing prospective study, called Pollution and Asthma Risk: an Infant Study (PARIS) birth cohort, found that children strongly sensitized to house dust mites at ages eight and nine had the highest risk of asthma and allergic rhinitis.⁷ A 2020 study evaluated the connection between ambient air pollution and childhood asthma, finding that children exposed to NO₂—a major traffic-related air pollutant—are more than twice as likely to have early-onset asthma.⁸ This risk is higher even when NO₂ levels are within World Health Organization guidelines, the study says.⁸

When comparing pediatric and adult-onset asthma, a cross-sectional study published in the Journal of Respiratory Medicine suggested that the immunopathology of pediatric asthma is more likely correlated to allergic phenotype and viral respiratory infection while adult-onset asthma is generally non-atopic in nature.⁹ Increasing evidence suggests that low-grade inflammation and pro-inflammatory cytokine status in adipose tissue is implicated in adult-onset asthma pathology.⁹

Comorbidities & Continuing Research

Adult-onset asthma may be more severe than pediatric asthma and is associated with higher risks of comorbidities such as obesity, diabetes, and metabolic syndrome.^9,10 A 2022 observational study (n=27,437) found that those participants with adult-onset asthma were more likely to be diagnosed with obesity (OR=1.46), hypercholesterolemia (OR=1.67), and osteoarthritis (OR=1.52).¹¹ In addition, as age of asthma diagnosis increased, odds of developing diabetes or hypertension also increased.¹¹

Studies suggest that certain comorbidities are more prevalent in severe asthma than in patients with mild-to-moderate disease.¹² Pulmonary comorbidities include upper respiratory tract disorders (obstructive sleep apnea, allergic and nonallergic rhinitis, chronic rhinosinusitis, nasal polyposis) and middle/lower respiratory tract disorders (chronic obstructive pulmonary disease, allergic bronchopulmonary aspergillosis and fungal sensitization, bronchiectasis, dysfunctional breathing). Extrapulmonary comorbidities include anxiety, depression, gastroesophageal reflux disease, obesity, and cardiovascular and metabolic diseases.¹² In the elderly population, asthmatics are at a higher risk for morbidity and mortality from their asthma than younger patients.¹³ Of note, evidence also suggests that elderly asthmatics are more likely to be underdiagnosed and undertreated.¹³

Asthma research continues to develop for both adult and pediatric populations, and studies suggest that overall, multiple immune cells are involved in the development of asthma such as T cells, macrophages, dendritic cells, eosinophils, neutrophils, mast cells, and basophils.¹⁴ Of particular interest, T cells and macrophages engage in crosstalk that transmits either anti-inflammatory or pro-inflammatory signals, and recent studies have highlighted that an imbalance of T cells or macrophage dysfunction contributes to the progression of asthma.¹⁴ In a 2020 article, researchers proposed a theoretical basis for this, putting forth the hypothesis of a connection between the cytokine storm and severe asthma. They believe that studying both the role of and the crosstalk between T cells and macrophages may contribute to the development of new, personalized treatments.¹⁴

Conclusion

For patients with asthma, young and old, intervening in the allergic march^6,15 and addressing asthmatic triggers, as Dr. Saxena describes, is an important part of a personalized approach to optimal health. The functional medicine model helps clinicians get to the root cause of asthma and develop individual treatment protocols, including dietary changes and other lifestyle modifications that help prevent and ease symptoms. Learn more at IFM’s upcoming Immune Advanced Practice Module (APM).

Related Articles

Environmental Exposures and Allergic Disease

Intestinal Permeability and Inflammatory Triggers

A PROACTIVE APPROACH TO PEDIATRIC ATOPY, RHINITIS, AND ASTHMA

References

1. National Center for Environmental Health. Most recent national asthma data. Centers for Disease Control and Prevention. Reviewed May 10, 2023. Accessed December 5, 2023. https://www.cdc.gov/asthma/most_recent_national_asthma_data.htm
2. Pavord ID, Beasley R, Agusti A, et al. After asthma: redefining airways diseases. Lancet. 2018;391(10118):350-400. doi:1016/S0140-6736(17)30879-6
3. Stanescu S, Kirby SE, Thomas M, Yardley L, Ainsworth B. A systematic review of psychological, physical health factors, and quality of life in adult asthma. NPJ Prim Care Respir Med. 2019;29(1):37. doi:1038/s41533-019-0149-3
4. Wang Z, Li Y, Gao Y, et al. Global, regional, and national burden of asthma and its attributable risk factors from 1990 to 2019: a systematic analysis for the Global Burden of Disease Study 2019. Respir Res. 2023;24(1):169. doi:1186/s12931-023-02475-6
5. Toppila-Salmi S, Lemmetyinen R, Chanoine S, et al. Risk factors for severe adult-onset asthma: a multi-factor approach. BMC Pulm Med. 2021;21(1):214. doi:1186/s12890-021-01578-4.
6. Yang L, Fu J, Zhou Y. Research progress in atopic march. Front Immunol. 2020;11:1907. doi:3389/fimmu.2020.01907
7. Gabet A, Rancière F, Just J, et al. Asthma and allergic rhinitis risk depends on house dust mite specific IgE levels in PARIS birth cohort children. World Allergy Organ J. 2019;12(9):100057. doi:1016/j.waojou.2019.100057
8. Lau N, Smith MJ, Sarkar A, Gao Z. Effects of low exposure to traffic related air pollution on childhood asthma onset by age 10 years. Environ Res. 2020;191:110174. doi:1016/j.envres.2020.110174.
9. de Boer GM, Tramper-Stranders GA, Houweling L, et al. Adult but not childhood onset asthma is associated with the metabolic syndrome, independent from body mass index. Respir Med. 2021;188:106603. doi:1016/j.rmed.2021.106603
10.  Baan EJ, de Roos EW, Engelkes M, et al. Characterization of asthma by age of onset: a multi-database cohort study. J Allergy Clin Immunol Pract. 2022;10(7):1825-1834.e8. doi:1016/j.jaip.2022.03.019
11.  Mendy A, Mersha TB. Comorbidities in childhood-onset and adult-onset asthma. Ann Allergy Asthma Immunol. 2022;129(3):327-334. doi:1016/j.anai.2022.05.005
12.  Rogliani P, Sforza M, Calzetta L. The impact of comorbidities on severe asthma. Curr Opin Pulm Med. 2020;26(1):47-55. doi:1097/MCP.0000000000000640
13.  Dunn RM, Busse PJ, Wechsler ME. Asthma in the elderly and late onset adult asthma. Allergy. 2018;73(2):284-294. doi:1111/all.13258
14.  Zhu X, Cui J, Yi L, et al. The role of T cells and macrophages in asthma pathogenesis: a new perspective on mutual crosstalk. Mediators Inflamm. 2020;2020:7835284. doi:1155/2020/7835284
15.  Biagini JM, Kroner JW, Baatyrbek Kyzy A, et al. Longitudinal atopic dermatitis endotypes: an atopic march paradigm that includes Black children. J Allergy Clin Immunol. 2022;149(5):1702-1710.e4. doi:1016/j.jaci.2021.09.036