Post-traumatic Stress Disorder and 20-Year Physical Activity Trends Among Women.

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.