Nearly 60% of Japanese adults aged 85 years and older receive support through the national Long-Term Care Insurance system, highlighting the need to identify individuals at risk of disability before functional decline begins. Although routine blood tests can detect many age-related diseases, reliable biomarkers for predicting future disability in the oldest adults have remained limited. Earlier identification could help support interventions that preserve independence and quality of life.

To address this challenge, researchers from Keio University in Japan, together with Dr. Luigi Ferrucci from the National Institute on Aging in the United States, analysed blood samples from adults aged 85–89 years. Using machine learning and statistical methods, the team examined 29 circulating proteins and evaluated their association with future disability and mortality. The findings were also independently validated using data from the Italian Invecchiare in Chianti (InCHIANTI) aging study. The research was published in GeroScience on June 27, 2026.

The initial study included 230 disability-free participants from the Kawasaki Aging Well-being Project, who were followed for approximately 4.5 years. Higher levels of beta-2-microglobulin (B2M) and cystatin C were consistently associated with an increased risk of developing disability, even after accounting for factors such as age, sex, kidney function, and lifestyle.

The findings were further supported by the Italian InCHIANTI study, where elevated levels of B2M and cystatin C were again linked to a greater risk of disability, particularly among adults aged 80 years and older. As both proteins can be measured using standard clinical blood tests, they may offer a practical way to identify older individuals who could benefit from earlier preventive support.

Overall, the study identifies B2M and cystatin C as promising blood-based biomarkers for predicting future disability in very old adults. Early risk identification could support timely interventions, such as exercise, nutritional support, and rehabilitation, helping more older adults maintain their independence while reducing the burden on long-term care systems.

Source: https://www.keio.ac.jp/en/org/kgri/news/20260820-01/