Physical, social factors may add up to faster brain aging: Study

Physical and social exposures, including air pollution, extreme temperatures, lack of green spaces and socioeconomic inequality, could together account for up to a nine times higher risk of accelerated brain aging, according to an analysis.

The study, published in the journal Nature Medicine, identified distinct but complementary brain markers -- physical exposures such as increased pollution and lack of green spaces were primarily associated with structural brain aging, affecting regions central to memory, emotional regulation, and autonomic (involuntary) functions.

Researchers from the Global Brain Health Institute (GBHI) at Ireland's Trinity College Dublin said the structural changes in the brain are consistent with mechanisms such as neuroinflammation, oxidative stress, and vascular dysfunction, all of which may contribute to tissue degeneration. They also found that social exposures -- poverty, inequality, and a lack of support -- are linked to a faster aging in brain areas responsible for thinking, emotions, and social behaviour.

The team looked at data of 18,701 individuals from across 34 countries, including India. They showed that the exposome, which is the cumulative of environmental, social, and sociopolitical exposures that one experiences throughout life, operate in a "syndemic manner" -- when two or more health problems occur together and interact in a way that makes each other worse.

"Exposome burden accounted for 3.3-9.1-fold higher risk of accelerated aging, exceeding effects of clinical diagnoses," the authors wrote.