Clinical and Free-Living Walking Measures Show Similar Mortality Discrimination

This Whitehall II accelerometer substudy followed 4,067 participants (mean age, 69.3 years; 74.4% male) from baseline in 2012–2013 through August 2024. Researchers measured clinical walking speed during a 2.44-m walking test and derived median and 95th-percentile walking cadence from nine days of wrist-worn accelerometer data. Deaths were identified through a national mortality register, and associations and predictive discrimination were assessed using Cox models and the Harrell C index.

Over a median follow-up of 11.8 years, each 1-SD higher value in clinical walking speed was associated with lower all-cause mortality (HR, 0.77; 95% CI, 0.71–0.84). The corresponding HRs were 0.83 (95% CI, 0.77–0.90) for median cadence and 0.82 (95% CI, 0.75–0.89) for 95th-percentile cadence. C indices were similar: 0.747 for clinical speed, 0.744 for median cadence, and 0.745 for 95th-percentile cadence. Only clinical walking speed improved discrimination in a model that already included mortality risk factors.

The findings suggest both approaches can be useful in population-based research, with method choice shaped by implementation and research objectives. This observational study establishes associations, not causality; its older, predominantly male cohort may also limit generalizability. The results do not establish that either measure should guide individual clinical decisions.