Abstract 31: Higher Levels of Light Intensity Physical Activity and Lower Sedentary Time are Associated With a Lower Risk of All-cause Mortality in Older Adults: The Framingham Heart Study

Abstract

Introduction: Habitual physical activity (PA) and less sedentary behavior have been associated with a lower risk of mortality in middle-aged adults. However, little is known about the associations of objectively-assessed PA of varying levels and sedentary time with mortality in community-dwelling older adults. Hypothesis: We hypothesized that higher overall PA and less sedentary time will be associated with a lower risk of all-cause mortality in older adults. Methods: We evaluated 1,262 Framingham Offspring Study participants (mean age 69 yrs, 54% women) with accelerometry-derived PA data (wear time ≥10 hours/day for at least 4 days using an Actical device) at their ninth examination (2011-2014). Multivariable Cox proportional hazards regression models were used to relate PA and sedentary time (separate model for each) with all-cause mortality adjusting for potential confounders. In sensitivity analysis to mitigate the potential impact of frailty on the associations evaluated, we excluded those with frailty at baseline. Results: Overall, 67 participants died during a median follow-up of 4.8 years (25 th -75 th percentiles: 4.3 - 5.3 [years]). Higher total PA, light intensity PA (LIPA), adherence to PA guidelines, and lower sedentary time were associated with a lower risk of all-cause mortality ( Table ). The results remained statistically significant even after excluding those with frailty. Higher LIPA and lower sedentary time were associated with a lower risk of all-cause mortality regardless of MVPA in both models including all participants and excluding those with frailty. Conclusions: In our investigation of a moderate-size sample of community-dwelling older adults, we confirmed that being physically active substantially lowered mortality risk. Additionally, our findings suggest that reducing sedentary time and increasing LIPA (regardless of MVPA) may be sufficient to reduce mortality risk in older adults. Additional studies of larger multi-ethnic samples of older adults are warranted to confirm our findings.