Illnesses in adulthood due to having lived through a war in childhood?

Exposure during childhood to wars or famines increases the risk of contracting cardiometabolic diseases and accelerates their development?

Two international studies, whose authors include researchers from the Higher Council for Scientific Research (CSIC) in Spain, measure the critical effects of wars and famines on the development of persistent diseases in adulthood. According to these two investigations, adult health is partly determined by the conditions of the first stages of life, even those that occurred before birth and, in addition, the most important mechanisms through which it can be influenced are epigenetic ( external factors that can affect the expression of genes without modifying the DNA).

As explained by Daniel Ramírez, a researcher at the Institute of Economy, Geography and Demography (IEGD) of the CSIC, traditionally, there was evidence that the stay in the womb was the critical period of vulnerability. The two new studies show that the period of the womb is the most critical; but also that in childhood there are developmental vulnerabilities that can lead to permanent alterations as a result of extreme exposure such as war or famine

The researchers analyzed two samples of 19,181 and 123,789 individuals to study the health of European survivors affected by World War II and the Dutch famine of 1944 (Hangerwinter) and have shown that exposure to extreme events (especially during pregnancy or the first childhood) is associated with an increased risk of persistent cardiovascular disease, diabetes, high cholesterol, and hypertension throughout life.

“The ultimate goal of this research is to show that these stages of life are very vulnerable. And in the same way, that they are vulnerable to permanent developmental alterations that lead to chronic diseases, they are also ‘vulnerable’ to their prevention” details the scientist, who alludes to the need for preventive public policies that delay the appearance and reduce the frequency of these diseases.

On the other hand, these are the first studies to provide evidence of a presupposition raised in previous research: the presence of differences in vulnerability by gender. Researchers have shown that male fetuses are more vulnerable in the womb than female fetuses.

Impact of war and famine on health

The results of the studies prove that exposure to war accelerates the onset of cardiovascular diseases, hypertension, high cholesterol and diabetes, which will develop an average of 2.2 years earlier in exposed people. And that, in addition, its effect on health varies depending on the time of exposure (the period in the womb and the first two years of life being especially critical).

A street in Paris that was part of the scene of World War II. (Photo: US Army)

For example, if malnutrition occurs during pregnancy, its consequences are mainly biological in nature (cardiometabolic diseases, muscle and bone problems, impaired hearing or vision, etc.). However, if it occurs at a later age (childhood or adolescence), more negative socioeconomic impacts are perceived (lower IQ, lower academic performance, etc.).

The researchers also looked at gender differences and found that males exposed to malnutrition in the womb show stronger negative consequences across a broader range of health conditions than their peers. This difference is also seen in socioeconomic status, with men showing substantially greater reductions in educational attainment as a result of exposure to famine.

Studies suggest that the impact of these events on cardiometabolic disorders is probably direct. This means that they are produced through latent biological processes rather than through difficulties experienced in childhood, delayed socioeconomic achievement, or unhealthy behaviors in adulthood (smoking and alcohol use).

Towards future research

War and malnutrition continue to plague the lives of millions of children around the world, especially in Africa, Asia and the Middle East. If exposure to war more than 75 years ago had lingering impacts on the health of Europe’s adult population, children exposed to these hostilities today will carry the health consequences long after the bombs and bullets have stopped.

“COVID-19, the locust plague in Africa, or the war in Ukraine have generated situations of stress and lack of access to food comparable to those experienced during the Second World War. According to the World Health Organization, during the pandemic, almost 12% of the world’s population experienced severe food insufficiency and, on a regular basis, around 10% of the world’s population is affected by hunger. So although the famine of World War II may seem distant, we still have similar situations today and we need to learn what to prioritize in these cases. In addition, we can learn how to develop preventive medicine policies and know which demographic cohorts to prioritize” declares Ramírez.

The scientist opens the door to direct future research to the study of intergenerational transmission and find out if the hardships suffered in the womb and at an early age transmit their pernicious effects through generations and through what mechanisms. In animals, transmission through epigenetic mechanisms is a reality, so if something similar were found in humans with exhaustive data, “one could even talk about implications for evolutionary theory.”

A solution to improve nutrition and eliminate malnutrition could lie in public policies focused especially on pregnant mothers. “Today, the World Health Organization focuses on the first 1,000 days of life as a preventive policy, which excludes pregnant women,” says Ramírez; and adds that “the most vulnerable are fetuses in their first trimester of pregnancy. With which, women with the slightest sign of a possible pregnancy should be prioritized in periods and environments of scarcity.

One of the studies is titled “Windows of Vulnerability: Consequences of Exposure Timing during the Dutch Hunger Winter. Population and Development Review”. And it has been published in the academic journal Population and Development Review.

The other is titled “Childhood exposure to war and adult onset of cardiometabolic disorders among older Europeans.” And it has been published in the academic journal Social Science & Medicine. (Source: Celia Ramos Vera / CCHS / CSIC)