Lower respiratory tract infection (LRTI) in early childhood was associated with nearly double the risk of dying prematurely from a respiratory illness in adulthood, accounting for one-fifth of premature adult deaths from respiratory disease, according to a new study released Tuesday.
The results of this long-running observational study were published in The Lancet Respiratory Medicine.1 To the researchers’ knowledge, this study is the first of its kind to find an association between infant LRTI and premature adult respiratory death, and the data came from what is believed to be the longest-running ongoing birth cohort study in the world.
The study used data that were prospectively collected by the UK Medical Research Council National Survey of Health and Development in a nationally representative population-based birth cohort enrolled during 1 week in March, 1946 in England, Scotland, and Wales. Parents gave permission to enroll 5362 infants, with follow-up happening 25 times between birth and age 73 years.
Of the original group of infants, 4032 were still included in the study at ages 20-25 years. The maximum follow-up of these participants lasted for nearly 48 years, starting in the first quarter of 1972, when the individuals were 26 years old.
In the survival analysis from 1972 onwards, 3589 participants aged 26-73 years were included, with premature adult death defined as death before age 75.
When the children were aged 2, parents or guardians were asked to report any LRTI occurrence happening up until that time, including bronchitis, bronchopneumonia, or pneumonia, along with frequency and treatment. As adults, they were asked about their smoking habits at age 20, 25, 36, 43, 53, 60–64, and 68.
The researchers prospectively linked incidences of early repiratory illness to the cause and date of death recorded in the National Health Service Central Register from 1946 to 2019. In addition, they adjusted their evaluations to include hazard ratios (HRs) and population attributable risk for socioeconomic status (SES), childhood home overcrowding, birthweight, sex, and smoking age at ages 20-25 years.
The results showed that 913 participants (25%) had an LRTI before the age of 2 years. By 2019, 674 (19%) of those patients had died before the age of 73 years. Among these deaths, 52 (8%) died from a respiratory disease, mostly chronic obstructive pulmonary disease (COPD).
Participants who had a LRTI in early childhood were 93% more likely to die by the age of 73 years due to a respiratory disease than those who had no LRTI during early childhood (HR 1.93; 95% CI, 1.10-3.37; P =.021).
The population attributable risk was 20.4% to 40% (95% CI, 3.8-29.8) "indicating that prevention of early childhood LRTI might reduce premature adult mortality from respiratory disease by one in five cases," noted an accompanying commentary on the findings.
The results indicate that these early illnesses led to 179,188 (95% CI, 3386-261,519) excess deaths between England and Wales from 1972 to 2019.
“Current preventative measures for adult respiratory disease mainly focus on adult lifestyle risk factors such as smoking,” said lead author, James P. Allinson, MD, PhD, Imperial College London, United Kingdom, in a statement.2 “Linking one in five of adult respiratory deaths to common infections many decades earlier in childhood shows the need to target risk well before adulthood.”
The findings were not explained by childhood poverty, overcrowded living conditions, pollution exposure, sex, adult smoking, or low birthweight, a proxy used for adverse prenatal exposures.
“The results of our study suggest that efforts to reduce childhood respiratory infections could have an impact on tackling premature mortality from respiratory disease later in life,” said Rebecca Hardy, PhD, Loughborough University and University College London, in a statement. “We hope that this study will help guide the strategies of international health organizations in tackling this issue.”
1. Soriano JB, Kendrick PJ, Paulson KR, et al. Prevalence and attributable health burden of chronic respiratory diseases, 1990–2017: A systematic analysis for the global burden of disease study 2017. The Lancet Respiratory Medicine. 2020;8(6):585-596. doi:10.1016/s2213-2600(20)30105-3
2. Contracting a respiratory infection in early childhood associated with a higher risk of dying from respiratory disease as an adult, study finds. The Lancet. www.thelancet.com/journals/lancet/article/PIIS0140-6736(23)00131-9/fulltext. Published March 7, 2023. Accessed March 7, 2023.