# Association of Physical Activity and Sitting Time Balance Index with all-cause and cause-specific mortality among cancer survivors in the USA: a cohort study

## TL;DR

Higher physical activity and less sitting time are linked to lower death risks in cancer survivors, according to a US study.

## Contribution

This study introduces the PASTBI index to assess the balance between physical activity and sedentary time in cancer survivors.

## Key findings

- Higher PASTBI scores were associated with 62% lower all-cause mortality in cancer survivors.
- Reduced sedentary time lowered CVD and cancer mortality risks, even without increased physical activity.
- Participants with the highest PASTBI scores had significantly lower risks of death from multiple causes.

## Abstract

This study examined the relationship between Physical Activity and Sitting Time Balance Index (PASTBI) and mortality outcomes, including all-cause, cardiovascular diseases (CVD)-, and cancer-specific mortality, in a nationally representative cohort of US cancer survivors.

Data were derived from the National Health and Nutrition Examination Survey 2007–2018. The PASTBI was calculated using information from the Global Physical Activity Questionnaire, with mortality data obtained through linked databases. Cox proportional hazards models with survey sample weights were applied to estimate hazard ratios (HRs) for all-cause, CVD-related, and cancer-related mortality, adjusting for potential confounders.

The analysis included 3334 cancer survivors, with an average follow-up of 72.02 months. Compared with quartile 1, participants in quartile 4 (highest PASTBI) had significantly lower mortality risks, including 62% lower all-cause mortality [HR = 0.38; 95% CI = 0.29–0.50], 55% lower CVD mortality [HR = 0.45; 95% CI = 0.23–0.86], and 56% lower cancer mortality [HR = 0.44; 95% CI = 0.27–0.71]. Additionally, while both quartile 1 and quartile 2 reported no physical activity time, individuals in quartile 2, who had shorter sedentary time, exhibited lower mortality risks [all-cause mortality HR = 0.62; 95% CI = 0.49, 0.79; CVD mortality HR = 0.54; 95% CI = 0.35, 0.84; cancer mortality HR = 0.75; 95% CI = 0.54, 1.06].

A higher PASTBI score, reflecting a better balance of physical activity and sedentary time, was associated with lower risks of all-cause, CVD-, and cancer-related mortality. Reducing sedentary time, even modestly, offers significant health benefits, independent of physical activity levels.

The online version contains supplementary material available at 10.1007/s00520-025-09709-x.