Children who contract lower respiratory tract infection (LRTI) at two years of age or younger could be more likely to die prematurely from that same condition as adults, a new study has found.
These types of infections were linked to one-fifth of the deaths.
The new study was conducted by a group of London researchers and led by Dr. James Peter Allinson of the National Heart and Lung Institute at Imperial College London. It was published in The Lancet this week.
It analyzed data from the Medical Research Council National Survey of Health and Development, which followed 3,589 participants in England, Scotland and Wales all born in March 1946.
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LRTIs are infections that impact the airway, including bronchitis, bronchiolitis, influenza and pneumonia.
Researchers identified the individuals who developed LRTI before their second birthday — based on reports from parents or guardians — then looked at public health records to determine which ones died from respiratory disease between the ages of 26 to 73.
Participants were also contacted 25 times during the eight-decade study.
After adjusting for socioeconomic position, gender, smoking habits, household overcrowding, birthweight and other factors, researchers found that participants who developed an LRTI as a young child were 93% more likely to die from respiratory disease by the age of 73.
Dr. Purvi Parikh, a New York-based allergist and immunologist with Allergy & Asthma Associates, was not involved in the study but said she was not surprised by the findings.
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"We already have data that respiratory viruses early in life can sensitize airways and predispose babies to developing asthma and COPD when they are older," she told Fox News Digital in an email.
Before age 2, she said, the lungs are still developing, as is the immune system.
"Damage to the lungs and airways during this time frame can have lasting effects on the lung tissue, including scarring and inflammation, and can also impact the immune system," she said.
The most common cause of respiratory-related death was chronic obstructive pulmonary disease (COPD), followed by acute lower respiratory tract infection, interstitial lung disease, bronchiectasis, respiratory disease due to external agents and other respiratory disease, the findings said.
The researchers wrote that infection during childhood could result in impaired lung function during the adult years — leading to a higher likelihood of respiratory disease.
The study authors admitted that, like all population survival studies, this one had some limitations and built-in bias.
"Although we adjusted for important socioeconomic factors and smoking, some adverse exposures remained unrecognized, and therefore unrecorded, in the 1940s," they wrote.
"Prospective investigation of unrecorded factors, including parental smoking and prematurity, awaits the maturation of subsequently initiated studies."
Lead author Dr. James Allinson pointed out that when the study began, there were likely more inequalities in health care among a generation that has now reached older adulthood.
"During their lifetime, average living conditions and health care in high-income countries (such as the U.S. and U.K.) has markedly improved," he said. "Therefore, children born today in these countries may be on course to develop better adult health."
However, Dr. Allinson added that there are still instances of inequity and poverty, even within high-income countries.
"Our data are likely very relevant to children born in many lower- and middle-income countries," he said.
Dr. Allison said current preventative measures for adult respiratory disease mainly focus on adult lifestyle risk factors, such as smoking.
"Linking one in five adult respiratory deaths to common infections many decades earlier in childhood shows the need to target the risk well before adulthood," he told Fox News Digital in an email.
"To prevent the perpetuation of existing adult health inequalities, we need to optimize childhood health," the doctor went on.
"Showing the early life origins of adult chronic diseases also helps challenge the smoking-related stigma attached to death from diseases such as COPD."
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Ultimately, Dr. Parikh said the study highlights the importance of the early developmental years in determining lifelong health. She recommends preventing lower respiratory tract infections by administering vaccines during early infancy.
"An RSV vaccine may soon be approved that an expectant mother could take during the third trimester to prevent this virus from causing severe disease in the newborn," she said.
(Pfizer anticipates getting approval to roll out its RSV vaccine in the U.S. and Europe in the fall, Reuters reported on Thursday.)
In the meantime, Dr. Parikh stressed the importance of vaccination for young children against pneumonia, influenza, COVID and pertussis to help prevent infectious diseases.
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Lead author Dr. Allinson also stressed the need for governments to tackle factors that endanger childhood respiratory health, including childhood exposure to pollution or cigarette smoke, poor quality housing, poor nutrition and inadequate health care provision.
"Many of these factors are closely connected to social disadvantage and poverty," he said.
While minor respiratory infections are common in childhood, the doctor warned that chronic or recurrent symptoms may indicate underlying health problems, such as asthma — which should be diagnosed and treated appropriately.