The aging process in China is accelerating, and the number of older adults with chronic diseases is increasing. The association between hypertension, along with its comorbidities, and dementia in older adults requires further investigation.

To investigate the association between hypertension, its comorbidities, and dementia in community-dwelling older adults, and to provide evidence for dementia prevention.

This study utilized cross-sectional data from 14 732 individuals aged ≥65 years from the China Multicenter Dementia Survey (CMDS, 2018-2023). Data on sociodemographic characteristics, chronic diseases, and cognitive function were collected. We employed a multivariate Logistic regression model to analyze the association between hypertension and its comorbidities and dementia in the total population and different age and sex groups.

Among the 14 732 older adults (≥65 years), 8 293 (56.3%) had two or more comorbidities, and 7 786 (52.9%) had hypertension along with other comorbidities. Of these hypertensive individuals, the numbers with 1, 2, 3, and 4 comorbidities were 2 569 (17.4%), 2 064 (14.0%), 1 018 (6.9%), and 443 (3.0%), respectively. Dementia was identified in 1 111 participants (7.5%). After adjusting for covariates, multivariate Logistic regression results showed that the risk of dementia in the hypertension-only group was 1.516 times (95%CI=1.014-2.267, P=0.042), and the risk of dementia among those with hypertension and 1 to 4 comorbidities was 1.879 times (95%CI=1.312-2.692, P=0.001), 2.071 times (95%CI=1.428-3.004, P<0.001), 2.338 times (95%CI=1.612-3.392, P<0.001), 2.591 times (95%CI=1.634-4.108, P<0.001). The highest risk of dementia was observed in individuals with hypertension coexisting with cerebrovascular disease (OR=2.550, 95%CI=1.384-4.700, P=0.003). In analyses stratified by sex and age, the risk of dementia increased significantly with the number of hypertension comorbidities (P<0.05). The strongest association was observed for hypertension coexisting with cerebrovascular disease, with adjusted odds ratios of 2.842 (95%CI=1.095-7.375, P=0.032) in men and 2.348 (95%CI=1.060-5.203, P=0.036) in women. In the group aged <75 years, the highest risk was observed for hypertension coexisting with diabetes (OR=2.833, 95%CI=1.046-7.675, P=0.041), while in the group aged≥75 years, the highest risk was observed for hypertension coexisting with cerebrovascular disease (OR=2.707, 95%CI=1.168-6.273, P=0.020). Among participants with hypertension and two comorbidities, the highest dementia risk was observed in those with coexisting heart disease and cerebrovascular disease (OR=3.559, 95%CI=1.338-9.468, P=0.011). Similarly, among those with hypertension and three comorbidities, the highest prevalence of dementia was observed in individuals with coexisting heart disease, cerebrovascular disease, and autonomic dysfunction (OR=3.881, 95%CI=1.736-8.677, P=0.001).

The prevalence of hypertension and its comorbidities is high among Chinese older adults. Patients with hypertension and its comorbidities have a significantly elevated risk of dementia, which varies by age and sex. These findings underscore the importance of optimized management of chronic diseases in this population. Implementing tailored prevention and treatment strategies based on individual characteristics could contribute to reducing the risk of dementia.