Association of Physical Activity with Risk of Dementia in Geriatric Depression Patients

Abstract Background Dementia prevention has emerged as a critical health concern. Nevertheless, the association between long-term physical activity and risk of dementia remains inconclusive, especially among geriatric patients with depression. We aimed to explore the association between long-term physical activity, following the diagnosis of geriatric depression, and risk of dementia, including Alzheimer’s disease, vascular dementia, and Lewy body dementia. Methods This was a nested case-control study. The participants were aged ≥ 60 years, diagnosed with geriatric depression, and had attended outpatient clinics at least three times. Data were obtained from the Korea National Health Insurance Service-Elderly Sample Cohort (January 1, 2002, to December 31, 2019). Each case was matched with up to five controls based on age, sex, date of depression diagnosis, and duration of follow-up. Long-term physical activity was assessed using two methods: adherence to World Health Organization recommendations and the total amount of physical activity measured in metabolic equivalents of task (MET)-min per week. Results A total of 12,022 participants, including 2,121 patients (17.6%) and 9,901 controls (82.4%), met the inclusion criteria. The mean follow-up period was 4.96 years. Among physically active individuals who adhered to WHO recommendations, a significantly reduced risk of dementia was observed. Additionally, a dose-dependent decline in the risk of dementia was observed. Analyses based on MET-min/week revealed a significantly lower risk in the top quartile, with a dose-dependent reduction. In subgroup analyses, a higher risk of dementia with a dose-dependent decrease was observed in men, individuals aged 70–79, and antidepressant users. Conclusions This study highlights an association between engaging in physical activity and a decreased risk of dementia in individuals newly diagnosed with geriatric depression. Consequently, encouraging geriatric patients with depression to participate in physical activity to prevent dementia is important.