Early Childhood Pneumonia/LRTI May Lead to Future Restrictive Spirometry Pattern

Individuals who had pneumonia or a lower respiratory tract infection (LRTI) during early childhood may exhibit reduced forced expiratory volume in 1 second (FEV₁) and forced vital capacity (FVC) later in childhood or during adulthood, according to study findings reported in The Lancet Child & Adolescent Health.

Researchers conducted a systematic review to assess whether having pneumonia or an LRTI in early childhood (ie, age 5 years or younger) affected FEV₁ and FVC values later in childhood or during adulthood. The reviewers searched studies in English in PubMed, Embase, and Web of Science databases from inception to October 28, 2021, with an updated search on May 12, 2022, with a case-control, cohort, or cross-sectional design that included documented pneumonia status in early childhood (age ≤5 years) in which participants also had spirometry testing of FEV₁ or FVC values after age 5 years.

A total of 14 studies (13 cohort, 1 cross-sectional) were included in the review, all published between 1990 and 2021. Their sample sizes ranged from 41 to 9175, with 23,276 total participants (9969 children and 13,307 adults).

For comparing spirometry values between groups with and without early childhood respiratory infections or pneumonia, the researchers found 8 studies that reported significantly lower FEV₁ values for the exposed group vs the unexposed control group. The values ranged from -49 mL (95% CI, -88 to -9) to -210 mL (95% CI, -390 to -129) for studies that reported raw values, and from -0.22 (95% CI, -0.31 to -0.12) to -1.80 (95% CI, -3.40 to -0.20) for Z scores. Unchanged FEV₁ values were reported in 5 studies and ranged from -180 mL (95% CI, -562 to 202) to -7 mL (95% CI, -55 to 41), and 1 study found that FEV₁ values were nonsignificant in the opposite direction.

FVC values after early childhood respiratory infections or pneumonia were reported in 12 studies, with 4 finding significant decreases in FVC that ranged from -98 mL (95% CI, -162 to -34) to -77 mL (95% CI, -94 to -60), and Z scores ranging from -3.2 (95% CI, -4.8 to -1.6) to -0.13 (95% CI, -0.22 to -0.04). Also, 6 additional studies found a decrease in FVC that ranged from -190 mL (95% CI, -627 to 247) to -15 mL (95% CI, -58 to 28). No change in FVC was reported in 1 study, and another study found a mean increase in FVC, with Z scores of 4.1 (95% CI, 1.3-6.9).

A total of 5 studies categorized exposures in at least 1 subgroup as pneumonia or as serious respiratory or lung infection, and 1 of the studies combined pneumonia and bronchitis findings. In 4 studies, significant reductions in FEV₁ values were reported after early childhood pneumonia compared with individuals without childhood pneumonia, and the other study found no change.

The researchers noted that only 2 studies had data from an upper-middle-income country or an indigenous population and disagreement between them made it difficult to establish the effect of early childhood pneumonia on lung function within disadvantaged populations. Also, 10 studies used parent-reported or self-reported medical histories, so reporting bias was a limitation.

“We observed reductions in both FEV₁ and FVC values in childhood and adulthood following early childhood respiratory infection, including pneumonia, which were statistically significant in the majority of included studies, and no change in a minority of studies,”

“Most studies that investigated FEV₁ and FVC values reported similar effect sizes for both outcomes, suggesting that early childhood respiratory infection might be associated with a future pattern of restrictive lung function,” stated the investigators. “There is substantial evidence to suggest that even small losses in lung function are associated with future cardiopulmonary morbidity and all-cause mortality.”

Disclosure: Some of the study authors declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of authors’ disclosures.