New research suggests that being born prematurely or with excessive or reduced fetal growth may increase the risk of developing atrial fibrillation later in life. These findings highlight how birth outcomes affect long-term cardiovascular health and emphasise the importance of further research and preventive strategies. Understanding the consequences of adverse birth outcomes may enable early interventions to be developed to moderate the risks.
Atrial fibrillation is widespread cardiac arrhythmia leading to increased mortality and morbidity, primarily from stroke and heart failure. Although atrial fibrillation is common among middle-aged and older individuals, the existing risk factors for atrial fibrillation do not fully explain how it develops among younger people. The link between fetal growth and cardiovascular diseases has gained attention recently, but its association with the risk of atrial fibrillation has seemed inconsistent. Researchers investigated these associations in a new population-based study.
“Our study shows that adverse birth outcomes such as preterm birth and excessive fetal growth are associated with an increased risk of atrial fibrillation throughout childhood and up to middle age, whereas reduced fetal growth is solely linked to atrial fibrillation during childhood. These findings emphasise how birth outcomes affect long-term cardiovascular health and highlight the need for early interventions and preventive strategies targeting individuals at higher risk,” says first author Fen Yang, PhD student at the Department of Global Public Health, Karolinska Institutet, Stockholm, Sweden.
Increased risk of atrial fibrillation during childhood
The study used prospectively recorded nationwide data from national health registries in Denmark, Sweden and Finland. The study analysed information on live singleton births from various time periods in each country and followed up on these individuals until specific end-point dates, including more than 8 million individuals who were followed up to the age of 49 years.
“Preterm birth has previously been linked to various cardiovascular diseases such as hypertension, ischemic heart disease, stroke and heart failure. However, the associations between these birth outcomes and atrial fibrillation have been uncertain. And the well-established risk factors for atrial fibrillation, such as age, sex, genetic factors and lifestyle choices, do not fully account for how it develops in younger populations. Thus, there was a need to further investigate the causes of atrial fibrillation among children and young adults,” says principal investigator Krisztina László, Associate Professor at the Department of Global Public Health, Karolinska Institutet and Senior Lecturer at the Department of Public Health and Caring Sciences at Uppsala University in Sweden.
By examining a larger population, the study sought to shed light on these associations. The goal was to determine whether preterm birth and being small or large for gestational age are associated with atrial fibrillation risk during various life stages. To ensure robustness in their findings, the researchers implemented a sibling design that accounted for potential confounding by shared familial factors.
“We found that both preterm birth and being large for gestational age were associated with an increased risk of atrial fibrillation during childhood and up to the age of 49 years. In contrast, being small for gestational age was only linked to an increased risk of atrial fibrillation during childhood. These findings were consistent even when considering sibling analysis,” explains Krisztina László.
Genetics and familial environment may play a modest role
Atrial fibrillation, characterised by irregular heart rhythm, is known to increase the likelihood of stroke and other cardiovascular problems. It primarily affects middle-aged and older individuals and is relatively rare among young people, with the prevalence ranging from 0.12% to 0.16%.
“The risk increased by 30% for those born prematurely, 55% for individuals with excessive fetal growth, and 71 percent for those who experienced both preterm birth and excessive fetal growth relative to the unexposed,” explains Fen Yang.
The study was observational, meaning it could not establish causal relationships. There are several potential explanations the link of preterm birth and abnormal fetal growth, with risk of atrial fibrillation. Shared genetic background, maternal factors, socioeconomic status, lifestyle and other confounders may contribute to these associations. However, adjusting for various maternal characteristics did not significantly alter the associations.
“Shared genetic and familial environmental factors may play a modest role in the associations between preterm birth, being large for gestational age and atrial fibrillation, but they may be more important for being small for gestational age and atrial fibrillation. Another possible explanation is that preterm birth, being small for gestational age and being large for gestational age may cause cardiac remodelling and dysfunction during fetal development.”
Crucial for safeguarding
The researchers suggest that future investigations should delve deeper into the connections between preterm birth, fetal growth and the risk of atrial fibrillation throughout a person’s lifetime, including their later years.
“By uncovering these associations, we can enhance understanding of atrial fibrillation and and hopefully develop targeted interventions to mitigate its impact on individuals' health. If confirmed in future studies, The findings may call for heightened surveillance and monitoring for AF in individuals who have experienced adverse birth outcomes,” according to Krisztina László.
Based on data from Sweden’s National Board of Health and Welfare, an estimated 5% of newborns in Nordic countries are delivered prematurely. Previous research indicates that individuals born prematurely or with restricted fetal growth have a slightly higher risk of developing cardiovascular diseases later in their lives, including ischaemic heart disease, stroke and heart failure.
“Detecting and managing potential cardiovascular risks, including atrial fibrillation, are crucial for safeguarding the health of the affected individuals and society as a whole. By improving understanding of the factors contributing to atrial fibrillation, we can take proactive steps to prevent its onset and minimize its effects,” concludes Krisztina László.
