Preterm birth was associated with higher risk of adult asthma and chronic obstructive pulmonary disease (COPD), a study finds.

“Preterm birth affects lung health in many ways, and earlier studies have established that preterm birth is a risk factor for lung health in childhood,” said Kari Risnes, a professor at the Norwegian University for Science and Technology, and one of the study’s authors, in a statement.1 "The current study shows that the risk extends at least up to middle age.”

The results of this population-based study were published in the European Respiratory Journal.2

Although preterm birth is known to affect the lungs in many ways, little is known on how these breathing problems present themselves later into adulthood.

This study included over 2.6 million people from nationwide register data on people born in Finland and Norway. In Finland, 4.8% of individuals were born preterm (n = 706,707) between 1987 to 1998 and 5% were born pre-term in Norway (n = 1,669,528) from 1967 to 1999. The researchers also obtained follow-up register data on the amount of care episode for asthma and COPD in Finland between 2005 to 2016 and in Norway from 2009 to 2017. Finally, the researchers estimated the odds ratio (OR) for having a care episode with either asthma or COPD.

As a result, the odds of having an obstructive airway disease in adulthood were 2- to 3-fold for those born extremely preterm, before gestational age at 28-weeks, or between 28 to 31-weeks, compared to those born full-term (39 to 41-weeks). Among individuals born at 32 to 33, 34 to 36, or 37 to 38-weeks, the odds were 1.1- to 1.5-fold.

These associations were similar across both Finnish and Norwegian data among individuals ages 18 to 29 and 30 to 50 years.

Individuals born at less than 28-weeks had the highest association for COPD at ages 30 to 50 years (OR, 7.44; 95% CI, 3.49-15.85), followed by those born 28 to 31-weeks (OR, 3.18; 95% CI, 2.23-4.54), and (OR, 2.32; 95% CI, 1.72-3.12) for those born 32-33-weeks. Lastly, the researchers found bronchopulmonary dysplasia in infancy increased the odds even more for those born less than 28-weeks and between 32 to 31-weeks preterm.

The researchers acknowledge some limitations to this study, including the fact that individual asthma and COPD diagnoses couldn’t be independently verified using clinical function measures, and that their results do not show the full spectrum of these respiratory conditions, only the most severe asthma and COPD cases.

However, despite these limitations, the researchers think their results illustrate consistent and significant associations between children born prematurely and the odds of those individuals having asthma or COPD later in adulthood.

“High risk groups of preterm born individuals, such as extremely or very preterm or those with a history of BPD [bronchopulmonary dysplasia], could benefit from more systematic follow-up with specialized teams who have knowledge on risks, possible prevention strategies, early diagnosis, and treatment,” concluded he researchers of this study. “In these groups, the excess risks are clinically significant and call for particular diagnostic vigilance when individuals born preterm present with respiratory symptoms.”


1. Children born preterm are more likely to have asthma or COPD in adulthood. EurekAlert! Published March 30, 2023. Accessed April 7, 2023.

2. Pulakka A, Risnes K, Metsälä J, et al. Preterm birth and asthma and COPD in adulthood: A nationwide register study from two Nordic countries. European Respiratory Journal. 2023:2201763. doi:10.1183/13993003.01763-2022

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