Demographic characteristics (n = 5,789).

The study aimed to investigate the survival rate of patients with dementia according to their level of physical activity and body mass index (BMI). A total of 5,789 patients with dementia were retrieved from the 2009–2015 National Health Insurance Sharing Service databases. Survival analysis was used to calculate the hazard ratio (HR) for physical activity and BMI. The study sample primarily comprised older adults (65–84 years old, 83.81%) and female (n = 3,865, 66.76%). Participants who engaged in physical activity had a lower mortality risk (HR = 0.91, p = 0.02). Compared to the underweight group, patients with dementia who had normal weight (HR = 0.86, p = 0.01), obesity (HR = 0.85, p = 0.03) and more than severe obesity (HR = 0.72, p = 0.02) demonstrated a lower mortality risk. This study emphasizes the significance of avoiding underweight and engaging in physical activity to reducing mortality risk in patients with dementia, highlighting the necessity for effective interventions.