Is Accelerated Aging Linked to Having More Chronic Conditions?

Man being chased down a hill by a clock. Harvy

Having 2 or more chronic illnesses is known as multimorbidity, which is a way of measuring a person’s physical health without reference to any specific disease. Multimorbidity is increasingly common among older adults, as aging itself is a risk factor for developing chronic conditions. This MIDUS study is one of the first to look at whether accelerated aging is associated with multimorbidity. Estimates of biological and brain age and how they differ from a person’s actual chronological age have recently emerged as a way of measuring accelerated aging. This study looked at whether being older (in terms of biological and brain assessments) than one’s actual age was associated with disease accumulation. It was also the first attempt to explore how biological and brain age are related to mental health multimorbidity.

Researchers looked at the following:

    • Multimorbidity, defined as having 2 or more of 13 different categories of chronic conditions during the last 12 months, including diabetes, asthma, hypertension, HIV/AIDS, tuberculosis, neurological disorders, stroke, ulcer, arthritis, cancer, heart trouble, obesity, or high cholesterol.
    • Mental health multimorbidity, which was defined as having 2 or more psychiatric or addictive conditions, such as depression, anxiety disorder, or alcohol or drug abuse.
    • Biological age was computed using machine learning models with a comprehensive set of 15 biological measures, such as BMI, blood pressure (systolic), cholesterol (HDL, LDL, total), triglycerides, HbA1C, and fasting glucose. A biological age gap indicative of accelerated aging was present if biological age was older than chronological age.
    • Brain age was determined from brain images taken via MRI.

Results showed that:

    • A larger biological age gap was significantly associated with an increased risk of multimorbidity.
    • Both accelerated biological and brain age were associated with increased risk of mental health
    • Brain age was not significantly associated with multimorbidity. However, results examined by gender suggested that the effect of brain age on multimorbidity was less among females. The lack of significant results could be due to the small sample size in the MIDUS Neuroscience project. Since this is the first study to look at brain age and multimorbidity, future studies with larger sample sizes are needed.

The top predictors for estimating biological age were total cholesterol, blood-fasting IGF1, bone-specific alkaline phosphatase, and blood pressure. Total cholesterol, LDL, and triglycerids were also important. Since these are modifiable factors, they represent possible avenues for future treatment of multimorbidity. Additionally, the results suggest that accelerated aging may be a shared pathway for multiple chronic conditions. Early detection of accelerated aging before the onset of chronic illness may suggest new means of disease prevention.

Source: Zhang, F., Chang, H., Schaefer, S. M., & Gou, J. (2023). Biological age and brain age in midlife: Relationship to multimorbidity and mental health. Neurobiology of Aging, 132, 145-153.

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