UCSF

INTRODUCTION: Post-traumatic stress disorder (PTSD) may be associated with physical inactivity, a modifiable lifestyle factor that contributes to risk of cardiovascular and other chronic diseases; however, no study has evaluated the association between PTSD onset and subsequent physical activity (PA) changes. METHOD: Analyses were conducted between October 2014 and April 2016, using data from the ongoing Nurses' Health Study II (N=50,327). Trauma exposure and PTSD symptoms were assessed using two previously validated measures, the Brief Trauma Questionnaire and Short Screening Scale for DSM-IV PTSD. Average PA (hours/week) was assessed using self-report measures at six time points across 20 years (1989-2009). Linear mixed models with time-updated PTSD assessed differences in PA trajectories by trauma/PTSD status. Among a subsample of women whose trauma/PTSD onset during follow-up, group differences in PA patterns before and after onset were assessed using linear spline models. RESULTS: PA decreased more steeply over time among trauma-exposed women reporting four or five (β= -2.5E^-3, SE=1.0E^-3, p=0.007) or six or seven PTSD symptoms (β= -6.7E^-3, SE=1.1E^-3, p<0.001) versus women without trauma exposure, adjusting for potential confounders. Among a subsample of women whose trauma/PTSD symptoms onset during follow-up, no differences in PA were observed prior to onset; after onset, women with six or seven PTSD symptoms had a steeper decline (β= -17.1E^-3, SE=4.2E^-3, p<0.001) in PA over time than trauma-exposed women without PTSD. CONCLUSIONS: Decreases in PA associated with PTSD symptoms may be a pathway through which PTSD influences cardiovascular and other chronic diseases.