New Delhi: Respiratory infections contracted during early childhood are associated with an increased risk in death from respiratory illness as an adult, according to a new study published in the Lancet.

The first-of-its-kind study spanning over seven decades suggests that people who had a lower-respiratory-tract infection (LRTI), such as bronchitis or pneumonia, by the age of two were 93% more likely to die prematurely from respiratory disease as adults, regardless of the socioeconomic background or the smoking status.

The study of 3,589 people over 73 years estimates early childhood LRTI was linked to 179,188 excess deaths across England and Wales over the 47 years between 1972 and 2019, equivalent to one-fifth of the premature deaths from respiratory disease in this period.

According to the authors of the report, these findings challenge the misconception that adult mortality from respiratory disease is only linked to smoking in adulthood, and highlight the need to implement interventions earlier in life to prevent childhood LRTI and improve the health of children suffering from such infections.

Chronic respiratory diseases pose a major public health problem, with an estimated 3.9 million deaths in 2017, accounting for 7% of all deaths worldwide. Chronic obstructive pulmonary disease (COPD) caused most of these deaths.

Infant LRTIs have been shown to be linked to the development of adult lung function impairments, asthma and chronic obstructive pulmonary disease, but it was previously unclear if there existed a link to premature death in adulthood.

“Current preventative measures for adult respiratory disease mainly focus on adult lifestyle risk factors such as smoking. 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. To prevent the perpetuation of existing adult health inequalities we need to optimise childhood health, not least by tackling childhood poverty. Evidence suggesting the early life origins of adult chronic diseases also helps challenge the stigma that all deaths from diseases such as COPD are related to lifestyle factors,” said James Allinson, Imperial College London, UK and the lead author of the study.The study used data from a nationwide British cohort (the National Survey of Health and Development), which recruited individuals at birth in 1946, and looked at health and death records up to the year 2019. Of the 3,589 study participants, 25% (913/3,589) had an LRTI before the age of two. By the end of 2019, 19% (674/3,589) of the participants had died before the age of 73 years. Among these 674 premature adult deaths, 8% (52/674) died from respiratory disease, mostly COPD.

An analysis adjusting for socioeconomic background during childhood and the smoking status suggests children who had an LRTI by the age of two were 93% more likely to die prematurely as adults from respiratory disease, than children who had not had an LRTI by age two. This equates to a 2.1% rate of premature adult death from respiratory disease among those who had an LRTI in early childhood, compared to 1.1% among those who did not report a LRTI before the age of two.

While this risk accounts for one in five premature respiratory-caused adult deaths, those attributable to smoking account for three in five in England and Wales over the same period.

Having an LRTI before the age of two was only associated with an increased risk of premature death from respiratory diseases, and not other illnesses, such as heart disease or cancers.