Early infections in childhood drive long-term health risks

By Dr. Chinta SidharthanReviewed by Susha Cheriyedath, M.Sc.Jan 8 2025

New research reveals how frequent infections in the first three years of life shape a child's long-term health, urging pediatricians to act early for better outcomes.

Study: Burden of Infections in Early Life and Risk of Infections and Systemic Antibiotics Use in Childhood. Image Credit: UvGroup / Shutterstock

In a recent study published in JAMA Network Open, a team of scientists in Denmark investigated how common infections in early childhood impact the likelihood of experiencing severe infections and requiring antibiotics later in childhood. They tracked infection episodes from birth to age three and explored their influence on health outcomes through age 10 or 13, providing insights for pediatric prognosis and care.

Background

Infections during childhood significantly affect health and development and contribute to global morbidity and mortality. Frequent infections in early life may predispose children to chronic conditions, such as asthma, allergies, metabolic disorders, and recurrent severe infections. Furthermore, social and environmental factors, including urban living, maternal smoking, and attending childcare facilities, are known to influence infection rates.

Respiratory infections, which are most common in childhood, can lead to long-term lung issues, while gastrointestinal and febrile illnesses are also prevalent among children. Previous research has highlighted associations between infection burden and antibiotic use, but comprehensive data from longitudinal studies are lacking.

Moreover, despite the importance of understanding early-life infections for health trajectories, gaps remain in determining how infection types and frequencies affect later outcomes. Addressing these gaps could enhance preventive strategies and treatment planning for vulnerable populations, reducing the long-term impact of infections during childhood.

The Current Study

In the present study, the researchers utilized longitudinal data from the Copenhagen Prospective Studies on Asthma in Childhood (COPSAC2010) cohort conducted in Denmark. This study followed 614 children from birth to age 10 or 13.

Data collection included detailed daily diaries maintained by parents from birth to three years, symptom records, physician-confirmed diagnoses, and medications for conditions such as colds, pneumonia, acute otitis media (middle ear infection), tonsillitis, fever, and gastroenteritis. The study found a mean of 16.4 infection episodes per child between birth and age three, with colds being the most frequent. These entries were validated during scheduled clinical visits.

The team categorized and analyzed the infection episodes to measure their association with later moderate-to-severe infections and systemic antibiotic use. They also retrieved data on clinical follow-ups, including physician-reported diagnoses and prescriptions from age three onwards, from the national databases. The study excluded children with congenital or immune deficiencies to ensure generalizability to healthy populations.

Covariates such as socioeconomic factors, maternal behaviors, sibling presence, and environmental exposures were adjusted for in the analysis, mitigating potential confounders. The infection burden was analyzed using quasi-Poisson regression models, which provided accurate estimates despite data variability.

The study also conducted subtype analyses to evaluate the impact of specific infections, such as pneumonia or cold episodes, on later risks. Acute airway samples were collected from children with severe respiratory symptoms during the first three years, and viral pathogens, including rhinoviruses and enteroviruses, were identified.

Major Findings

The study found that early-life infections strongly influenced later health risks. Each early infection episode increased the risk of later moderate-to-severe infections by 5% (adjusted incidence rate ratio [AIRR], 1.05; 95% CI, 1.02–1.08) and systemic antibiotic treatments by 2% (AIRR, 1.02; 95% CI, 1.01–1.04).

Furthermore, children with high infection burdens (≥16 episodes by age three) had significantly greater risks of severe infections (AIRR, 2.39) and antibiotic treatments (AIRR, 1.34) compared to those with lower infection burdens. Children in the highest quartile of infection burden were up to three times more likely to experience severe infections compared to those in the lowest quartile (AIRR, 3.02; 95% CI, 1.51–6.53).

The subtype analysis revealed that early pneumonia episodes were associated with a nearly 50% higher risk of later pneumonia (AIRR, 1.48; 95% CI, 1.34–1.62), while colds and acute otitis media also contributed to elevated risks. Viral infections, especially rhinoviruses and enteroviruses, were linked to an increased likelihood of future pneumonia.

Urban living was associated with higher infection rates, but the findings remained consistent after adjusting for demographic and environmental variables.

Conclusions

To conclude, the study demonstrated that frequent infections during early childhood significantly increased the risk of contracting severe infections and requiring antibiotic treatments later in life.

These findings emphasize the importance of proactive pediatric care and early monitoring for children with high infection burdens. Pediatricians and caregivers should prioritize mitigating infection risks during early years to improve long-term health outcomes and reduce the disease burden in childhood and beyond.