To examine differences in all-cause mortality risk reductions associated with daily steps across socioeconomic strata.

Prospective cohort study using NHANES data (2011–2014) with a median follow-up of 5.9 years among 7032 U.S. adults aged 18–80 years. Exposure was accelerometer-measured daily steps categorized by socioeconomic status using the Ratio of Family Income to Poverty (RFIP; low <1.30, medium 1.30–1.84, high ≥1.85). Outcome was all-cause mortality determined via linkage to the National Death Index through December 2019. Cox proportional hazards models with restricted cubic splines and Relative Excess Risk due to Interaction (RERI) were applied.

Over the follow-up, 452 participants died. Higher daily steps were associated with reduced mortality risk in all socioeconomic groups. However, socioeconomically advantaged individuals experienced greater risk reductions per 1000 daily steps compared to disadvantaged groups (RERI for low vs. high RFIP: –0.115, 95 % CI: –0.189, –0.042). Individuals with low RFIP required 1.2–2.3 times more steps to match the mortality benefits seen in high RFIP groups.

Socioeconomically disadvantaged populations may not benefit equally from daily steps. Addressing the factors contributing to this discrepancy will help maximize the health benefits of walking for all, thereby reducing overall health disparities.