The methods library

What does biological age actually measure?

Ten approaches, explained. Distinguish chronological-age prediction, health-outcome associations, pace of aging and fitness comparisons.

Health-outcome association

Phenotypic Age / PhenoAge

A published model built from routine blood chemistry and chronological age.

Chronological-age model

A statistical framework for combining age-related biomarkers.

Model-dependent age estimate

Algorithms that interpret patterns of DNA methylation.

Mortality-risk association

An outcome-oriented clock using methylation-derived surrogates.

Pace of aging

A methylation-based estimate of the pace of aging.

Age correlation

An age-related signal from sugar structures on antibodies.

Model-dependent outcome association

Statistical age models built from protein measurements.

Fitness comparison

Cardiorespiratory fitness translated into an age comparison.

Metabolic comparison

A device-specific comparison based on estimated energy expenditure.

Wearable trend

Age-like scores calculated from sensor and activity data.