Association of accelerometer-derived step volume and intensity with hospitalizations and mortality in older adults:A prospective cohort study

Purpose:This study aimed to examine the associations of accelerometer-derived steps volume and intensity with hospitalizations and all-cause mortality in older adults.Methods:This prospective cohort study involved 768 community-dwelling Spanish older adults(78.8±4.9 years,mean±SD;53.9% females)from the Toledo Study for Healthy Aging(2012-2017).The number of steps per day and step cadence(steps/min) were derived from a hip-mounted accelerometer worn for at least 4 days at baseline.Participants were followed-up over a mean period of 3.1 years for hospitalization and 5.7 years for all-cause mortality.Cox proportional hazards regression models were used to estimate the individual and joint associations between daily steps and stepping intensity with hospitalizations and all-cause mortality.Results:Included participants walked 5835± 3445 steps/day with an intensity of 7.3± 4.1 steps/min.After adjusting for age,sex,body mass index(BMI),education,income,marital status and comorbidities,higher step count(hazard ratio(HR)=0.95,95% confidence interval(95%CI:0.90-1.00,and HR=0.87,95%CI:0.81-0.95 per additional 1000 steps) and higher step intensity(HR=0.95,95%CI:0.91-0.99,and HR=0.89,95%CI:0.84-0.95 per each additional step/min) were associated with fewer hospitalizations and all-cause mortality risk,respectively.Compared to the group having low step volume and intensity,individuals in the group having high step volume and intensity had a lower risk of hospitalization(HR=0.72,95%CI:0.52-0.98) and all-cause mortality(HR=0.60,95%CI:0.37-0.98).Conclusion:Among older adults,both high step volume and step intensity were significantly associated with lower hospitalization and all-cause mortality risk.Increasing step volume and intensity may benefit older people.