As global temperatures rise due to climate change, researchers from the Yale School of Public Health (YSPH) have identified a concerning association between high ambient temperatures during pregnancy and an increased risk of childhood leukemia. Published in The Lancet Planetary Health journal, this study marks the first to directly examine how prenatal exposure to hot temperatures may impact cancer risk in children.
Lead author Tormod Rogne, an assistant professor of epidemiology at YSPH, emphasized the study’s implications: “Our research contributes to a growing body of evidence suggesting that high ambient temperatures not only affect immediate health outcomes but may also contribute to long-term chronic diseases.”
The study focused on acute lymphoblastic leukemia (ALL), the most prevalent childhood cancer, which disproportionately affects Latino children in the United States. Previous research has established that many cases of childhood ALL originate prenatally, with environmental factors during pregnancy playing a critical role.
“Exposure during the first trimester appears particularly significant due to its influence on early hematopoiesis,” noted Xiaomei Ma, senior author and professor of epidemiology at YSPH, referring to the development of blood cells.
The study analyzed data from California birth records and the California Cancer Registry, covering children diagnosed with ALL before the age of 14. Researchers assessed the association between ambient temperature and ALL risk on a weekly basis, focusing on warmer months from May to September.
Of the 6,258 children diagnosed with ALL and the 307,579 without, the study found a notable increase in ALL risk during gestational week eight, correlating with higher weekly mean temperatures. Specifically, a weekly mean temperature of 30°C (86°F) during this critical period was associated with nearly double the risk compared to a mean temperature of 10°C (50°F).
The research utilized NASA’s Daily Surface Weather Data for North America to estimate ambient temperature exposure and considered a range of factors from birth records, including gestational age, demographics, and birth weight. Despite these findings, the precise mechanisms linking prenatal heat exposure to ALL remain unclear, with potential contributors including epigenetic changes, inflammation, or oxidative stress.
The study underscores the need for further research into the health impacts of climate change, particularly on vulnerable populations. “It’s increasingly evident that communities, especially racial and ethnic minorities, are disproportionately affected by heat exposure due to factors such as occupational hazards and residential segregation,” the researchers highlighted.
As temperatures continue to rise globally, understanding and mitigating the risks associated with prenatal heat exposure could prove crucial in safeguarding children’s health.
