Abstract P297: Intensity-specific Physical Activity Measured by Accelerometry and Mortality in Women: The OPACH Study
Background: Associations for cardiovascular disease (CVD) and all-cause mortality with intensity-specific physical activity (PA) exposures assessed by questionnaire may be underestimated by exposure measurement error, especially in older adults. We examined accelerometer measured PA and CVD and all-cause mortality in 6,374 race-ethnically diverse women (White, 49.4%, Black 33.7%, Hispanic 16.9%) ages 63-91 (mean 78.7 years) followed a mean of 2.5 years as part of the Objective Physical Activity and Cardiovascular Health (OPACH) Study.
Methods: Vector magnitude counts/15-sec epoch from hip worn Actigraph GT3X+ triaxial accelerometers (required ≥4 of 7 days with ≥10 hr/day wear time) were used to define time spent in low light (LLPA; 19-225 counts/15-sec), high light (HLPA; 226-518), and moderate-to-vigorous (MVPA; ≥519) PA based on cutpoints determined from a calibration study among similarly aged women. Cox regression was used to estimate hazard ratios (HR) and 95% confidence intervals (CI) for these associations.
Results: There were 270 (4.2%) all-cause deaths and 78 (1.2%) CVD deaths during 14,205 person-years of follow-up. Adjusting for awake-time accelerometer wear-time, age, and race, HRs (CI) for CVD mortality associated with a 30-min/day increment in PA were 0.82 (0.71,0.96) for LLPA; 0.48 (0.38,0.61) for HLPA; and 0.53 (0.38, 0.74) for MVPA; and for all-cause mortality were 0.86 (0.79, 0.93), 0.61 (0.54, 0.69), and 0.57 (0.48, 0.67) respectively. These associations were similar following additional adjustments for smoking, age at menopause, and number of prevalent comorbidities (CVD HRs = 0.83, 0.49, 0.54, respectively, P≤0.01 all; all-cause HRs = 0.86, 0.62, 0.58, respectively, P<0.001 all). Similar results were observed after discarding the first 6 months of follow-up (CVD HRs = 0.84, 0.49, 0.50; all-cause HRs = 0.87, 0.63, 0.59). In a final model mutually adjusting for total light PA (LLPA and HLPA combined) and MVPA, each 30-min increment in light PA and MVPA was associated with HRs for CVD mortality of 0.84 (0.75, 0.93) and 0.67 (0.47, 0.96) respectively; and with all-cause mortality of 0.90 (0.85, 0.95) and 0.66 (0.55, 0.80), respectively.
Conclusions: Higher levels of both light intensity PA and MVPA measured by accelerometry are associated with lower CVD and all-cause mortality in older women. Because light intensity PA accounts for the majority of daily PA energy expenditure in older women’s lives, these results could have important public health implications and should be confirmed.
Author Disclosures: M.J. LaMonte: None. E. Rillamas-Sun: None. K.R. Evenson: None. I. Lee: None. D.M. Buchner: None. C. Di: None. A.Z. LaCroix: None.
- © 2017 by American Heart Association, Inc.