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Association between early viral lower respiratory tract infections and subsequent asthma development
Sebastien Kenmoe1,2, Etienne Atenguena Okobalemba3, Guy Roussel Takuissu4
1Department of Microbiology and Parasitology, University of Buea, Buea 00237, Cameroon.
Insights
Infant lower respiratory tract infections (LRTIs) in children under two years old significantly increase the risk of developing asthma later in life, regardless of the specific virus. This finding highlights the importance of understanding LRTIs for long-term respiratory health.
Area of Science:
- Pediatric Respiratory Medicine
- Epidemiology
- Immunology
Background:
- The link between human respiratory syncytial virus (HRSV) bronchiolitis and childhood asthma is established.
- Long-term outcomes of other viral lower respiratory tract infections (LRTIs) in infants are less understood.
Purpose of the Study:
- To examine the association between infant LRTIs and the subsequent development of asthma.
- To evaluate the impact of confounding factors on this relationship.
Main Methods:
- Systematic review and meta-analysis of cohort studies published up to October 2021.
- Included studies compared asthma incidence in children with and without LRTI at ≤ 2 years.
- Random effects model used for meta-analysis; heterogeneity assessed via stratified analyses.
Main Results:
- 15 articles (18 studies) met inclusion criteria.
- Infant LRTIs (≤ 2 years) are linked to a 5-fold increased risk of asthma up to age 20 (OR=5.0).
- Association remained significant for doctor-diagnosed, current asthma, and current medication use; heterogeneity was observed.
Conclusions:
- Viral LRTIs in children under two years old increase the risk of developing asthma, irrespective of the virus or confounding factors.
- Parents and healthcare providers should be aware of this increased asthma risk.
Background:
The association between hospitalization for human respiratory syncytial virus (HRSV) bronchiolitis in early childhood and subsequent asthma is well established. The long-term prognosis for non-bronchiolitis lower respiratory tract infections (LRTI) caused by viruses different from HRSV and rhinovirus, on the other hand, has received less interest.
Aim:
To investigate the relationship between infant LRTI and later asthma and examine the influence of confounding factors.
Methods:
The PubMed and Global Index Medicus bibliographic databases were used to search for articles published up to October 2021 for this systematic review. We included cohort studies comparing the incidence of asthma between patients with and without LRTI at ≤ 2 years regardless of the virus responsible. The meta-analysis was performed using the random effects model. Sources of heterogeneity were assessed by stratified analyses.
Results:
This review included 15 articles (18 unique studies) that met the inclusion criteria. LRTIs at ≤ 2 years were associated with an increased risk of subsequent asthma up to 20 years [odds ratio (OR) = 5.0, 95%CI: 3.3-7.5], with doctor-diagnosed asthma (OR = 5.3, 95%CI: 3.3-8.6), current asthma (OR = 5.4, 95%CI: 2.7-10.6), and current medication for asthma (OR = 1.2, 95%CI: 0.7-3.9). Our overall estimates were not affected by publication bias (P = 0.671), but there was significant heterogeneity [I 2 = 58.8% (30.6-75.5)]. Compared to studies with hospitalized controls without LRTI, those with ambulatory controls had a significantly higher strength of association between LRTIs and subsequent asthma. The strength of the association between LRTIs and later asthma varied significantly by country and age at the time of the interview. The sensitivity analyses including only studies with similar proportions of confounding factors (gender, age at LRTI development, age at interview, gestational age, birth weight, weight, height, smoking exposure, crowding, family history of atopy, and family history of asthma) between cases and controls did not alter the overall estimates.
Conclusion:
Regardless of the causative virus and confounding factors, viral LRTIs in children < 2 years are associated with an increased risk of developing a subsequent asthma. Parents and pediatricians should be informed of this risk.
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