Minimum changes in sleep, physical activity, and nutrition associated with clinically important reductions in all-cause mortality risk: a prospective cohort study

Abstract

Background: Sleep, physical activity, and nutrition (SPAN) are crucial modifiable factors for health, yet most research has examined them independently rather than exploring their combined and incremental impact on disease risk and mortality. Objective: To determine the collective associations of SPAN exposures and establish clinically relevant targets for reducing all-cause mortality risk. Methods: This study included 59,078 UK Biobank participants with valid wearable tracker and nutrition data (Median age [IQR]: 64.0 [7.8] years; 45.4% male). Sleep duration (hours/day) and moderate to vigorous physical activity duration (MVPA; mins/day) were calculated using a machine learning based wearable data schema. A 10-item diet quality score (DQS) assessed the consumption of vegetables, fruits, fish, dairy, whole grains, and vegetable oils, as well as lower intakes of refined grains, processed meats, unprocessed red meats, and sugar-sweetened beverages using a food frequency questionnaire. The DQS assigned values from 0-10 for each component, totalling 100 points, with higher values indicating higher diet quality. Associations with all-cause mortality were explored using Cox proportional hazard models with combinations of SPAN exposure tertiles. Results: During the median 8.1-year follow-up period, 2,458 deaths occurred. MVPA exhibited the strongest overall effect on mortality risk, followed by sleep (with a U-shaped relationship), and diet quality. Compared to the referent group of combined SPAN exposure (lowest tertiles for all three behaviours), the optimal SPAN combination involving moderate sleep duration (7.2-8.0 hours/day), high MVPA (42-103 mins/day), and high DQS (57.5-72.5) was associated with a hazard ratio (HR) of 0.45 (95% CI: 0.37, 0.53). Relative to the 5th percentile of sleep (5.5 hours/day), physical activity (7.3 mins/day), and nutrition (36.9 DQS), a minimum increase of 15 mins/day of sleep, 1.6 min/day MVPA, and 5 DQS points was associated with a 10% reduction in all-cause mortality risk (HR: 0.90; 95% CI: 0.88, 0.93). Additionally, compared to the referent group, an additional 75 mins/day of sleep, 12.5 min/day MVPA, and 25 DQS points was associated with a 50% reduction in all-cause mortality risk (HR: 0.50; 95%CI: 0.44, 0.58). Conclusion: These findings underscore the importance of combined incremental lifestyle modifications in reducing the risk of all-cause mortality.