Salivary cortisol patterns linked to cognitive decline in older adults

A large, racially diverse cohort study conducted in Chicago examined diurnal salivary cortisol in nearly 4,000 older adults (mean age ≈ 77). Researchers found that cortisol indices were associated with baseline cognitive performance and with the rate of cognitive decline over an 11‑year follow‑up. Medium to high intraday variability was related to slower decline, while the highest cumulative cortisol exposure predicted faster decline. Racial differences in cortisol rhythms were observed—Black participants showed flatter slopes and lower variability—but the associations with cognitive decline were similar across groups. The study did not find a link between cortisol patterns and incident Alzheimer disease. As an observational investigation, causality cannot be established, but the findings suggest salivary cortisol could serve as an early biomarker of neurocognitive aging.