A groundbreaking international study published in Nature Medicine reveals that exposure to environmental pollutants, social inequality, and weak democratic institutions can significantly accelerate brain aging and increase the risk of cognitive decline.
The study, which analyzed data from 161,981 individuals across 40 countries, introduced a new concept called “Behavioral-Biological Age Gaps” (BBAGs)—the difference between chronological age and expected biological age based on health, cognition, and life circumstances.
A research team from the American University in Cairo (AUC), led by Professor Mohamed Salama of the Institute of Global Health and Human Ecology, along with postdoctoral fellow Sara Mostafa, contributed to the study as part of a global collaboration involving researchers from Latin America, Africa, Asia, Europe, and North America.
“Our study shows that where you live—your exposure—can age your brain by several years,” the authors wrote. The findings demonstrate that accelerated brain aging is associated with measurable structural exposures, including air pollution, economic disparity, gender inequality, and limited political freedoms.
Salama emphasized the importance of inclusive research, stating, “Scientific diversity is no longer optional. Including countries from Africa and the Middle East is essential to understanding global risks to brain health.”
Lead author Agustin Ibanez of the Global Brain Health Institute (GBHI) noted that brain health must be understood as a product of environmental and political conditions—not merely personal choices. “Our biological age reflects the world we live in,” he said.
The study warns that larger BBAGs strongly predict future declines in cognition and daily functioning. It presents compelling evidence that aging is not just a biological process but also a political and environmental phenomenon.
“The conditions in which people live—pollution, instability, inequality—are leaving measurable marks on the brain across 40 countries,” said Hernan Hernandez, the study’s first author.
The authors call on public health leaders and policymakers to act urgently to improve environmental conditions and governance structures, emphasizing that aging interventions must go beyond individual lifestyle changes to address systemic inequities.