Getting older is an inevitable part of life, but the rate at which we age and the risk of developing chronic diseases can vary significantly among individuals. Research has increasingly focused on understanding the concept of biological age, which is a more informative marker of disease risk and mortality than chronological age. By developing biological aging clocks specific to organ systems, tissue types, and aging-related diseases, scientists hope to slow age-related decline, reduce the risk of chronic diseases, and promote healthy longevity.
A Comprehensive Study of Biological Aging
A recent study in the UK Biobank cohort has taken a significant step towards understanding the complex nature of human aging. The researchers established normative models of aging-related decline for multiple brain and body systems in a large and diverse population. This comprehensive investigation has revealed the multisystem nature of human aging in health and chronic disease.
The study found that an organ’s biological age selectively influences the aging of other organ systems, revealing a multiorgan aging network. It also reported organ age profiles for 16 chronic diseases, showing that advanced biological aging extends from the organ of primary disease to multiple systems. The researchers found that advanced body age is associated with several lifestyle and environmental factors, leukocyte telomere lengths, and mortality risk. Importantly, their work predicts survival time and premature death with a high level of accuracy.
Implications for Precision Geriatric Medicine
By examining the heterogeneity of biological aging across individuals and organs, this study holds substantial promise for precision geriatric medicine and related clinical translation. Identifying deviations from expected aging-related decline in certain organs years before disease diagnosis can help pinpoint individuals who may benefit from early interventions aimed at slowing the aging of specific body systems and organs.
Lifestyle and Environmental Factors
The study highlights the importance of addressing lifestyle and environmental factors that can influence biological aging. Personalized interventions, such as limiting tobacco smoking and alcohol intake, exercise, education, sleep hygiene, and maternal nutrition, can be targeted at specific body systems. Efforts requiring national inputs, such as reductions in socioeconomic inequality, air pollution, and improvements in residential greenspace and natural environment coverage, can also play a significant role in slowing biological aging.
Challenges and Future Directions
While this study addresses several challenges hindering the clinical translation of biological aging research, certain caveats remain. First, biological aging is multifaceted, and standardized measures of organ age are yet to be developed. Second, the study was unable to assess the influence of brain aging on body systems due to the non-randomized participant assessment schedule. Third, the generalizability of the findings to diverse ethnicities and socioeconomic backgrounds remains to be assessed. Finally, some imaging modalities were only acquired in select individuals, limiting the data available for some organ clocks.
This groundbreaking research into biological aging has mapped a multiorgan aging network for the human body. By understanding the complexities of aging and the interplay between organ systems, researchers are paving the way for precision geriatric medicine and the development of new strategies to potentially limit organ-specific aging, ultimately promoting a healthier, longer life for individuals.
Tian, Y.E., Cropley, V., Maier, A.B. et al. Heterogeneous aging across multiple organ systems and prediction of chronic disease and mortality. Nat Med (2023). https://doi.org/10.1038/s41591-023-02296-6