Late-life falling and depressive symptoms associated with the risk of Parkinson’s disease: a nationwide cohort data analysis

BACKGROUND: This study aimed to evaluate the relationship between the history of late-life falling and the development of Parkinson’s disease (PD) and investigate whether depressive symptoms interact with falling to increase PD risk. METHODS: We identified 1,223,726 subjects without PD who underwent the National Screening Program for Transitional Age at 66 years between 2009 and 2013 using the National Health Cohort database. In this program, every participant was assessed whether they experienced falling for the past six months. Depressive symptoms were evaluated with a three-item questionnaire extracted from the Geriatric Depression Scale. Incident PD was traced for a mean 4.23 ± 1.50 years. Cox proportional hazard regression models were used to assess the risk of PD by falling history with and without depressive symptoms after adjusting for other confounding variables. RESULTS: In this cohort, the PD incidence rate was 1.30 and 1.03 cases per 1000 person-years in groups with and without falling and 1.34 and 1.00 cases per 1000 person-years in groups with and without depressive symptoms. The predictive risk of PD was increased by either a history of falling (HR = 1.24; 95% CI 1.11–1.40) or the presence of depressive symptoms (HR = 1.31; 95% CI 1.21–1.42) after adjusting for possible confounding variables. For individuals with both falling and depressive symptoms, PD risk increased further (HR = 1.66; 95% CI 1.40–1.97), but with sex-differences. The two factors increased PD risk in a sub-additive manner in men, whereas synergistically in women. CONCLUSIONS: This national cohort database shows that late-life depressive symptoms accompanied by a falling event pose an increase in the risk of PD in older adults.