Perhaps the cruelest aspect of climate change is that it disproportionately affects the people least responsible for the planet’s cooking emissions, especially the poorest among us. Among other things, experts predict that global warming will expose 70% of the working population to health risks and could ultimately kill around a billion people, most of them poor. But it is not only the environment that will be affected, but the very bodies of people.
A new study in the journal Nature Climate Change reveals a new way that climate change disproportionately affects poor people: it changes their brains before they are even born.
“These impacts could worsen under the current climate change emergency.”
It all depends on the delicate relationship between external temperatures and the proper development of the fetus.
Researchers from the Netherlands, the United States and Spain followed 2,681 children over a period of more than a dozen years from a group of patients known as the Dutch birth cohort. generation R”. The Dutch Generation R birth cohort (which initially included 9,896 pregnant women; many dropped out of the study over the years) existed to test whether prenatal exposure to extreme heat and cold impacted neurodevelopment.
By examining patients with magnetic resonance imaging (MRI) over the years, they have learned that infants and young children exposed to heat and cold during pregnancy and their early years are more likely during preadolescence to develop have structural problems with the myelin and white matter in their brain. . Additionally, their brains will have reduced mean diffusivity (MD), or the ease with which water molecules move through brain tissue.
Disproportionately, children who suffer in this way come from low-income backgrounds.
“Children living in poorer neighborhoods were more vulnerable to exposure to cold and heat,” the authors write. “Our results suggest that exposure to cold and heat during periods of rapid brain development could have lasting impacts on children’s white matter microstructure, a risk that needs to be considered in the context of climate change in progress.”
More than half of the participants were from the Netherlands, 10 percent were from Suriname or the Netherlands Antilles, and the rest came from countries as diverse as Turkey, Morocco, and other “non-Western countries.” After more than three-quarters of participants dropped out before their children aged between nine and 12 (at the time they were studied using MRI), the majority of those who remained were from ” parents with a high level of education, Dutch, with a household income above 2,200 euros per month and without previous children.” The authors acknowledge that this demographic homogeneity may somewhat bias the results.
Despite this, these results are encouraging.
“We found an association between exposure to cold and heat during pregnancy, infancy and early childhood and overall MD in children aged 9 to 12 years,” the authors write. “These impacts could worsen in the current climate emergency, given the projected increase in global temperatures and the potential increase in extreme cold events.”
They hypothesize that this means that children who were exposed to extreme heat or cold during their prenatal stage or early infancy will not develop healthy white matter, or the part of the brain that is vital for intellectual activities, balance and enabling various regions of the body. to connect and receive signals.
After noting that there was no association between exposure to cold and heat early in life and overall fractional anisotropy, a measure of connectivity in the brain, between ages 9 and 12, the Authors stated that children living in disadvantaged neighborhoods (socio-economic status) appear more vulnerable to cold and heat.
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“More research is needed to elucidate the impacts of cold and heat on children’s brain development, particularly at younger ages.”
The new study is particularly important because it is the first to examine the physical structures of the brain in relation to temperatures. Previous research has examined how children’s behavior changes depending on temperature, but none has directly attributed these behavioral observations to physical structures in the brain.
“As children with psychopathological symptoms and poorer cognitive performance appear to have suboptimal brain structural connectivity, defined by poorer white matter microstructure, we hypothesized that cold and hot temperatures might have impacts negative on brain white matter microstructure,” the authors write. “Since white matter growth is particularly rapid in infants and young children, we also hypothesized that there may be specific periods of increased vulnerability to cold and heat exposure during these periods of development. Their new research confirmed these hypotheses.
This isn’t the only study that shows climate change is harming people’s health. For example, there is growing evidence that climate change reduces male fertility because sperm rely on lower ambient temperatures to develop properly. As temperatures rise, human testicles, literally overheated, seem to be strained beyond their healthy capabilities.
“High scrotal temperatures have been associated with decreased sperm count and motility (ability to move), so increasing ambient temperature (e.g. due to global warming) may decrease sperm quality “, Dr. Shanna Swan, environmental and reproductive epidemiologist at the Icahn School. of Medicine at Mount Sinai, told Salon in March: “Increased temperatures, especially in extremely hot regions, can lead to heat stress, which can negatively affect sperm production and quality. Additionally, the consequences of global warming, such as food insecurity, natural disasters and economic instability can contribute to chronic stress that negatively affects sperm quality, reproductive hormones and fertility.
Swan added: “Separating the causal from the correlative is extremely difficult, as you know! »
Because it is indeed difficult to separate casual links from correlatives, even the authors of the new book Nature Climate Change agree that more research is needed to prove that these links go beyond simple correlation. It is important to find ways to alleviate this accelerating crisis.
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