Purpose of the study: Trajectories of physical activity (PA) and sedentary time (ST) after military separation are likely important determinants of women's health outcomes later in life, because low PA and high ST are known contributors to premature mortality risk. Our objective was to compare longitudinal trajectories of recreational PA and ST between Veteran and non-Veteran postmenopausal women from the Women's Health Initiative (WHI).
Design and methods: Women Veteran (n = 3,719) and non-Veteran (n = 141,800) WHI participants were included. Self-reported participation in recreational PA, converted to metabolic equivalent (MET)-hours/week, was prospectively assessed over 8 years. Self-reported ST, defined as hours/day sitting or lying down, was collected at baseline and at Years 3 and 6. Generalized estimating equations were used to compare trajectories of PA and ST between Veterans and non-Veterans, adjusted for demographics and lifestyle behaviors.
Results: Veterans had higher baseline PA than non-Veterans (13.2 vs 12.5 MET-hours/week, p = .03). PA declined for both groups, with a steeper decline among Veterans (change/visit year -0.19 vs -0.02 MET-hours/week; interaction p < .001). At baseline, Veterans and non-Veterans had similar levels of ST (107.2 vs 105.9 hours/week, p = 0.42). Over time, ST remained stable among Veterans but declined slightly among non-Veterans (change/visit year -0.19 vs -0.49 hours/week; interaction p = .01).
Implications: The less favorable longitudinal trajectories of PA and ST we observed for women Veterans may contribute to worse health among these individuals later in life. Understanding barriers to enhancing PA and reducing ST in women Veterans could lead to more effective approaches to intervening on these health behaviors.
Keywords: Health behavior; Health trajectory; Longitudinal Study; Physical activity; Postmenopausal; Sedentary behavior; Sedentary lifestyle; Women Veterans.
Published by Oxford University Press on behalf of the Gerontological Society of America 2016.