CLOCK and dementia: Proteomics-based aging clocks (PACs) are promising biomarkers of aging because proteins expression changes with advancing age and they exert biological functions which can be potentially modified by lifestyle and pharmaceutical interventions.3,9 In this study, we created a proteomics-based aging biological clock across two stages of life namely, midlife and late-life, then tested the hypotheses that biological age acceleration would be associated with lower global and domain-specific cognitive function as well as greater risk of developing dementia.