Association between physical-activity trajectories and cognitive decline in adults 50 years of age or older

Aims To investigate the associations of physical-activity trajectories with the level of cognitive performance (CP) and its decline in adults 50 years of age or older. Methods We studied 38 729 individuals (63 +/- 9 years; 57% women) enrolled in the Survey of Health, Ageing and Retirement in Europe (SHARE). Physical activity was self-reported and CP was assessed based on immediate recall, verbal fluency and delayed recall. Physical-activity trajectories were estimated using growth mixture modelling and linear mixed-effects models were used to investigate the associations between the trajectories and CP. Results The models identified two trajectories of physical activity: constantly high physical activity (N = 27 634: 71%) and decreasing physical activity (N = 11 095; 29%). Results showed that participants in the decreasing physical-activity group exhibited a lower level of CP compared to the high physical-activity group (immediate recall: ss = 0.94; 95% confidence interval [CI] = 0.92-0.95; verbal fluency: ss = 0.98; 95% CI = 0.97-0.98; delayed recall: ss = 0.95; 95% CI = 0.94-0.97). Moreover, compared with participants in the constantly high physical-activity group, participants in the decreasing physical-activity group showed a steeper decline in all cognitive measures (immediate recall: ss = -0.04; 95% CI = -0.05 to -0.04; verbal fluency: ss = -0.22; 95% CI = -0.24 to -0.21; delayed recall: ss = -0.04; 95% CI = -0.05 to -0.04). Conclusions Physical-activity trajectories are associated with the level and evolution of CP in adults over 50 years. Specifically, our findings suggest that a decline in physical activity over multiple years is associated with a lower level and a steeper decline in CP.