Chronic, low-grade inflammation, sometimes called "inflammaging", is one of the most consistently identified drivers of age-related disease risk across cardiovascular, metabolic, and neurodegenerative conditions. Inflammatory markers measure this directly through blood tests for signaling molecules including CRP (C-reactive protein), IL-6 (interleukin-6), and TNF-alpha (tumor necrosis factor alpha), all already in routine clinical use for cardiovascular risk assessment well before longevity research adopted them.
That existing clinical infrastructure is what gives this biomarker category its strong evidence rating: these aren't experimental research assays, they're established lab tests with decades of outcome data behind them, now being reinterpreted through a longevity and biological-aging lens rather than a single-disease lens.
One connection worth noting: senescent cells, the target of senolytic therapies, are a major source of the inflammatory signaling that drives chronic inflammation with age. That's part of why inflammatory markers are sometimes used as an indirect readout in senolytic research, a drop in inflammatory markers after treatment is one of the signals researchers look for as early evidence that senescent cell clearance is having a biological effect.