Depression in older adults is associated with accelerated biological aging leading to excessive age-related medical morbidity, cognitive decline, and premature mortality. Previous studies in late-life depression (LLD) have reported the role of cellular senescence, a key hallmark of biological aging that can be assessed in peripheral blood, as an increased expression of senescence-associated secretory phenotype (SASP) proteins.
We measured a SASP index based on 22 proteins in 426 individuals diagnosed with LLD. We applied factor analyses to an extensive battery of clinical variables to group them into factors related to depression and anxiety, cognitive functioning, and physical health. We then tested the relationship between these factors and the SASP index.
Men presented a higher SASP index than women. Regression analyses showed a strong relationship between the SASP index and physical health and a weaker association with cognitive functioning but no association with depression and anxiety.
Our findings reinforce the role of physical health in the pathophysiology of LLD and support the notion of LLD as a systemic illness. Longitudinal studies are needed to understand if inhibition of cellular senescence should be considered in future efforts to prevent and treat LLD.