Women born prematurely are at greater risk of committing suicide

Not only are they the smallest among us, premature children also face health and life challenges that make them the most vulnerable. Generally speaking, they have a slightly higher risk of mortality due to illness. It is now apparent that they also have a higher risk of unexpected death from so-called external causes: road traffic accidents, substance abuse and suicide.

This has been revealed in a major Nordic study led by Professor Kari Risnes from the Faculty of Medicine and Health Sciences at NTNU. The researchers have analysed birth data and causes of death for nearly 37,000 individuals aged between 15 and 50 who were born prematurely in Norway, Sweden, Denmark and Finland.

One finding in particular surprised them.

Higher risk of suicide for women born prematurely

The study reveals that prematurely born women have a nearly 80 per cent higher risk of committing suicide compared to individuals born at full term. The researchers find no such elevated suicide risk in prematurely born men. Women born 7–17 weeks prematurely are actually almost as likely to commit suicide as men in the general statistics.

Pediatrician and Professor Kari Risnes. Photo: Sølvi W. Normannsen SHOW MORE

Suicide is a serious problem in society. The majority of suicides are committed by men, and it is the leading cause of death among young men in Norway, Europe and around the world.

“We don’t know why premature women now turn out to be at almost the same level,” said Risnes, who is an
expert in paediatric epidemiologyEpidemiology is the study of the occurrence of diseases in populations, the factors that determine variations in disease, and how health problems can be treated and controlled.at the Department of Clinical and Molecular Medicine.

Extra baggage

“What we do know is that both men and women born prematurely are more vulnerable to certain diseases. Some struggle mentally and socially, and experience other challenges as well,” said Risnes.

She also leads the NTNU life-course research group, which conducts population-based research on vulnerable children and young people.

Although many individuals who are born prematurely do very, very well, the paediatrician and researcher describes these vulnerabilities as extra baggage that they carry with them throughout their lives.

Associate Professor Signe Oppdal at the Department of Public Health and Nursing has led the analysis and is the lead author of the article on premature birth and mortality recently published in the BMC Medicine journal.

Require support and understanding

A full-term pregnancy lasts 40 weeks, and babies born before week 37 are considered premature. Today, the vast majority of premature babies survive. Even among babies born before week 28 of pregnancy – more than three months premature – survival rates exceed 80 per cent. That is far more than just a few decades ago.

“Survival rates have really increased, but some people born prematurely require more follow-up, and they need everyone around them to understand that they might experience challenges,” said Risnes.

Confirmation that premature babies are more vulnerable

Risnes has also led previous studies from the four Nordic countries. Research shows that premature children have a higher mortality rate as young adults compared with people born at term. They are more vulnerable to heart disease, chronic pulmonary diseases and diabetes than the general population. Other studies have shown that people born prematurely have an elevated risk of mental disorders.
Among other things, this may be linked to lower cognitive functions  (i: Various skills related to perception of surroundings, memory, understanding, decision-making ability, task execution, communication, and behaviour regulation).

Investigating correlations

Children and young people generally have a low risk of dying. It is the sudden, violent deaths from road traffic accidents, suicide and substance abuse that claim the most young lives – even though all of these are theoretically preventable. These external causes of death are three times higher in men than in women – and they explain much of the excess mortality found among young men.

The researchers set out to study whether and how the vulnerabilities of prematurely born individuals potentially manifested in these external causes of death.

Suspicions arose in 2017

As early as 2017, the researchers had data from Norway that pointed towards an elevated risk of suicide. Risnes said it has been important for them to be able to investigate this in a major study. In addition to the risk of suicide, they wanted to see whether prematurely born individuals are especially vulnerable to external, unnatural deaths such as road traffic accidents and substance abuse.

In addition, they wanted to investigate whether there are differences between the sexes.

The healthcare system is increasingly successful in saving younger and younger premature infants. At the same time, research continues to reveal more challenges faced by this group. Illustrative photo: Sarahbean / Shutterstock / NTB scanpix SHOW MORE

The girls surprised the researchers

So far, little research has been done on this topic. However, the Nordic research team has now shown that there is a correlation between premature birth and the risk of unexpected death. They have also shown that prematurely born women are just as vulnerable as men when it comes to suicide.

“The day we saw these girls right up here at the top of the graphs together with the boys, I must say, we were very surprised.  Our first thought was to check whether we had made a mistake or overlooked something. We checked and double checked to make sure, so we are confident the findings are reliable. There is a very good research team behind this study, and we find the same pattern in all four countries,” said Risnes, pointing to red and blue lines on a graph.

The figure illustrates deaths from external causes between ages 15 and 45, grouped by gestational age. Blue curves represent men, and red curves represent women. The dotted lines indicate the most prematurely born individuals. The occurrence of suicide is shown in the diagram at the bottom left. Here, the researchers used data from all individuals born in Norway after 1967 and in Sweden after 1974. (Graphic: NTNU) SHOW MORE

Under the radar

The big question now is whether there is something specific about prematurely born girls that makes them especially vulnerable.

“We really know very little about this. It is a small and very special group. We also don’t know if this is just the tip of the iceberg. We feel compelled to delve deeper,” said the NTNU professor.

She points out that there is quite a large group of premature babies who struggle when growing up. These children still, and often to a large extent, go under the radar of the healthcare system, schools, and kindergartens.

Surprises from the Danes

When it comes to unnatural deaths, there are differences among the Nordic countries. This is something that has also been seen in other studies. The new study shows that young Swedish women who were born prematurely are at high risk of committing suicide in particular, with approximately the same rate as men. In Denmark, however, the death rate from suicide among people born prematurely is much lower than in the other Nordic countries – Danish men are actually at the same level as Swedish, Finnish and Norwegian women. The Danes also have a much lower rate of death from substance abuse than their Nordic neighbours.  The study shows that prematurely born men in Finland are particularly vulnerable to fatal road traffic accidents and deaths related to substance abuse.

Researcher and doctor – a fine balance

Risnes believes the strength of the study is that they have comparable data from four countries. She emphasizes that today’s neonatal care is very different from when the oldest participants in the study were born at the end of the 1960s.

The healthcare system is becoming increasingly successful at saving more and more premature babies.

At the same time, research is making us more aware of the increasing challenges faced by this group. Risnes is a paediatrician and an expert on premature babies, but she is also a researcher exploring the vulnerabilities and risks associated with being born too early – it can be a fine balance.

Understanding and tolerating differences

“Some people might see our research as labelling an entire group, which could cause concern. That said, we also note that patients and relatives want more knowledge. They want the people around them, such as kindergartens, schools, and the healthcare system, to understand and provide the support they need. Perhaps we as researchers can also help highlight that we all have strengths and vulnerabilities. In this way, we can contribute to society better understanding and accepting that people are different,” she said.

External causes of death. The figure shows deaths resulting from traffic accidents, suicides, and substance abuse in Denmark, Finland, Norway, and Sweden. Blue bars represent men, and red bars represent women. Each bar corresponds to a gestational age group: weeks 23–33 represent very preterm births, weeks 34–36 represent moderately preterm births, and weeks 39–41 represent full-term births. SHOW MORE

Identifying correlations and mitigating challenges

Premature birth is a risk factor that follows 6 per cent of the population throughout life. To mitigate the challenges they face, the researchers hope to investigate the latest findings more thoroughly.

When asked about the difference she hopes their research can make, Risnes highlights that it could be used for a much-needed update of the guidelines for the follow-up of premature infants(in Norwegian). The current guidelines are from 2007 and only apply to children up to the age of 5 years. For many people, it is only then that the challenges begin.

“That is when children start school, and it is precisely then that parents feel they need support the most,” said Risnes.

Reference: Josephine Funck Bilsteen, Signe Opdahl, Anna Pulakka, Per Ivar Finseth, Weiyao Yin, Kristine Pape, Jorun Schei, Johanna Mets, Anne‐Marie Nybo Andersen, Sven Sandin, Eero Kajantie, Kari Risnes: Mortality from external causes in late adolescence and early adulthood by gestational age and sex: a population-based cohort study in four Nordic countries
https://doi.org/10.1186/s12916-024-03731-2