AUTOIMMUNE diseases are associated with higher dementia risk and cognitive impairment in a nationwide Korean cohort.
Autoimmune Diseases and Dementia Risk
Using Korean National Health Insurance Service health screening data from 2002 to 2019, the investigators examined 8,743,801 person years to test whether autoimmune disease onset predisposes to later dementia.
Across the cohort, 8.3% of participants developed dementia. Any autoimmune disease was linked with a significantly higher risk of dementia, with a hazard ratio of 1.32 (95% confidence interval 1.29-1.35). When dementia subtypes were considered, the excess risk was most pronounced for Alzheimer’s disease with a hazard ratio of 1.36 (95% confidence interval 1.32-1.40), followed by vascular dementia with a hazard ratio of 1.21 (95% confidence interval 1.12-1.30) and unspecified dementia with a hazard ratio of 1.25 (95% confidence interval 1.18-1.33). These findings support chronic inflammation as an important contributor to the immunoneurological axis connecting systemic autoimmunity and neurodegeneration.
Cognitive Impairment and Connective Tissue Disorders
The investigators also assessed cognitive status using the Korean Dementia Screening Questionnaire Prescreening tool. Autoimmune diseases increased the odds of a positive dementia screen, with an odds ratio of 1.18 (95% confidence interval 1.12-1.24) compared with individuals without autoimmunity. Connective tissue disorders appeared particularly relevant, with an odds ratio of 1.24 (95% confidence interval 1.15-1.34), highlighting the burden of cognitive impairment in this subgroup.
From a clinical standpoint, the data suggest that patients with autoimmune diseases may cross the threshold into cognitive impairment earlier than their peers. The authors emphasise that dementia and cognitive decline should be considered part of the broader clinical trajectory for many autoimmune conditions, not only classic neuroinflammatory diseases.
Clinical Implications For Early Cognitive Screening
This large-scale cohort study reinforces the concept that chronic systemic inflammation can affect brain health over time. For clinicians caring for adults with autoimmune diseases, especially those living with longstanding disease activity, the results support a lower threshold for early cognitive screening and proactive discussion of memory, mood, and day to day function.
The study does not determine causality or specify which immunological pathways drive dementia risk, but it underscores the value of integrated care that links rheumatology, neurology, primary care, and mental health services. Incorporating structured cognitive screening into routine follow up for patients with autoimmune diseases may help identify at risk individuals earlier, when supportive interventions and risk factor management are most likely to preserve quality of life.
Reference: Lee W et al. The immuno-neurological axis: association between autoimmune diseases and dementia risk. Geroscience. 2025;doi:10.1007/s11357-025-01904-2.
