Lifetime physical activity influences Parkinson's disease progression

Introduction: Past studies suggested that Parkinson's disease (PD) patients who engage in physical activity (PA) after diagnosis have slower motor progression. Here, we examine the influence of lifetime PA prior to PD onset on motor, cognitive, and overall functional decline among PD patients. Methods: For 495 participants in the Parkinson's Environment and Gene (PEG) studies, we collected PA-related measures through interviews and quantified these using metabolic equivalents (MET) scores. PD progression was defined as time to a Unified Parkinson's Disease Rating Scale Part III (UPDRS-III) conversion to >= 35 points, Hoehn and Yahr (H&Y) >= 3, and a 4-point decline in Mini-Mental State Examination (MMSE). We used Cox frailty models to estimate hazard ratios and inverse probability weights to account for heterogeneity by enrollment wave and censoring. Results: For PD patients reporting the highest lifetime strenuous MET-h/wk (highest quartile), we estimated a lower HR for time-to-UPDRS-III-conversion (Q4 vs. Q1: HR = 0.56, 95 % CI = [0.36, 0.87]). Additionally, having engaged in any competitive sport also reduced the risk of reaching a UPDRS-III >= 35 points (low vs. none: HR = 0.61, 95 % CI = [0.44, 0.86]; high vs. none: HR = 0.63; 95 % CI = [0.44,0.86]); high levels of sports activities also affected progression on the H&Y scale (high vs. none: HR = 0.73; 95 % CI = [0.46,1.00]). Lifetime PA measures did not affect time-to-MMSE decline. Conclusion: Our study suggests that PD patients who engaged in higher levels of lifetime strenuous PA and competitive sports prior to PD diagnosis experience slower motor and overall functional decline, suggesting that lifetime PA may contribute to a physical reserve advantageous for PD patients.