A groundbreaking study conducted by the USC Leonard Davis School of Gerontology has shed light on the potential impact of extreme heat on accelerating biological aging in older adults. This study raises significant concerns about the long-term health implications of climate change and heat waves at a molecular level.
The research, published in the journal Science Advances, reveals that individuals living in neighborhoods with more days of high heat tend to exhibit greater biological aging compared to those residing in cooler regions. Biological age, which measures the body’s functionality at molecular, cellular, and system levels, is a key determinant of health and mortality risk.
Lead author Jennifer Ailshire, a professor of gerontology and sociology at USC Leonard Davis School, explains that exposure to extreme heat has long been associated with adverse health outcomes. However, the link between heat and biological aging has remained unclear until now.
The study analyzed over 3,600 participants aged 56 and older from various regions in the U.S. Blood samples were collected at different time points over a six-year period to assess epigenetic changes, specifically DNA methylation patterns. The researchers used epigenetic clocks to estimate biological ages and compared them with each participant’s heat index history and the number of heat days reported by the National Weather Service.
The results revealed a significant correlation between increased biological aging and greater exposure to extreme heat. Even after accounting for socioeconomic, demographic, and lifestyle factors, the association persisted. Individuals living in areas with frequent extreme heat days, such as Phoenix, Arizona, experienced up to 14 months of additional biological aging compared to those in cooler regions.
The study utilized three epigenetic clocks—PCPhenoAge, PCGrimAge, and DunedinPACE—to analyze epigenetic aging over different time frames. The findings suggest that heat-related epigenetic changes can occur rapidly and accumulate over time, contributing to accelerated biological aging.
Older adults are particularly vulnerable to the effects of high heat, especially when combined with high humidity. The researchers stress the importance of considering both temperature and humidity levels when assessing heat-related health risks for older populations.
Moving forward, the research team plans to investigate additional factors that may increase vulnerability to heat-related biological aging and explore potential clinical outcomes. The study’s findings also highlight the need for policymakers and urban planners to prioritize heat mitigation strategies and age-friendly infrastructure designs to protect vulnerable populations.
In conclusion, this study underscores the critical importance of understanding the impact of extreme heat on biological aging and health outcomes, particularly for older adults. By raising awareness and implementing effective mitigation strategies, we can work towards safeguarding the health and well-being of aging populations in the face of climate change challenges.
