The Impact of Insomnia on Dementia Risk in Hypertensive Individuals

BACKGROUND/AIM: Hypertension is a vascular disorder that affects both the vascular system and neural tissue. Insomnia may further impair health and contribute to dementia development. This study examined the association between insomnia and dementia in individuals with hypertension using a retrospective cohort design. PATIENTS AND METHODS: Participants diagnosed with hypertension were classified into insomnia (n=97,751) and non-insomnia groups. Primary outcomes included Alzheimer's disease, vascular dementia, and Parkinson's disease. Cox proportional hazards models were used to estimate adjusted hazard ratios (aHRs) and 95% confidence intervals (CIs). RESULTS: During follow-up, the insomnia group included 759, 611, and 825 cases of Alzheimer disease, vascular dementia, and Parkinson disease, respectively, compared with 677, 499, and 546 cases in the non-insomnia group. Insomnia was significantly associated with higher risks of Alzheimer's disease (aHR=1.178, 95% confidence interval=1.062-1.307), vascular dementia (aHR=1.282, 95% confidence interval=1.139-1.443), and Parkinson's disease (aHR=1.582, 95% confidence interval=1.420-1.763). Cumulative incidences for all outcomes were also higher in the insomnia group. Sensitivity analyses showed elevated risks of Alzheimer's disease in middle-aged and older individuals with high hemoglobin A1c (HbA1c); increased vascular dementia risk in those of younger and older age, high low-density lipoprotein cholesterol, and elevated HbA1c; and higher Parkinson's disease risk among individuals with low high-density lipoprotein cholesterol, high low-density lipoprotein cholesterol, or elevated HbA1c. CONCLUSION: Insomnia substantially increases dementia risk among individuals with hypertension, underscoring the clinical importance of sleep management in this population.