Dementia is one of the leading causes of death worldwide. Today, more than 50 million people have dementia, and by 2050, the number of cases may triple. Most patients with dementia reside in low- and middle-income countries. Since there is still no effective treatment for dementia, prevention remains a primary focus.
Hypertension is one of the risk factors for dementia. Several studies have shown that untreated hypertension increases the likelihood of developing dementia. Conversely, people undergoing hypertension treatment do not show this elevated risk. A meta-analysis of seven cohort studies involving over 17,000 participants with an average age of 74.5 years demonstrated that both excessively high and excessively low blood pressure can be equally harmful to the brain.
Some randomized controlled trials have tested antihypertensive drugs versus placebo on dementia risk in patients with hypertension or a history of stroke. These studies reported only modest reductions in dementia risk with antihypertensive treatment. However, until now, there was no conclusive evidence that lowering blood pressure helps prevent dementia in hypertensive patients.
Chinese researchers conducted a study in rural areas to investigate whether hypertension treatment reduces the risk of dementia. Within the CRHCP-3 project, patients with poorly controlled blood pressure received either standard care or intensive treatment aimed at maintaining their blood pressure below 130/80 mmHg over a four-year period. The goal was to determine if this approach could effectively prevent dementia under conditions of limited healthcare resources.
Study Results
Nearly 34,000 people from 326 villages participated in the study. Half of the participants received intensive hypertension treatment (intervention group), and the other half received standard medical care (control group). Both groups were comparable in age, gender, and cardiovascular risk. Participants were monitored for a period of four years, and dementia data were collected for over 28,000 individuals by the end of the study.
Blood Pressure Reduction
After four years, intensive treatment significantly lowered participants’ blood pressure: average systolic pressure decreased from 157.0 to 127.6 mmHg, and diastolic pressure from 87.9 to 72.6 mmHg. In the standard care group, the decrease was much less pronounced. As a result, 67.7% of the intervention group reached target blood pressure (<130/80 mmHg), compared to only 15% in the control group. Patients in the intensive treatment group more frequently took three antihypertensive medications, while the standard care group usually took just one. The most commonly used drugs were calcium channel blockers, diuretics, and ACE inhibitors.
Reduced Risk of Dementia and Mild Cognitive Impairment
After four years, dementia was diagnosed in 4.6% of participants in the intensive treatment group versus 5.4% in the standard care group. The intervention group also had fewer cases of mild cognitive impairment without dementia: 17.2% versus 20.7% in the control group. The combined evaluation of dementia and mild cognitive impairment showed a 16% risk reduction.
Cognitive health was better preserved in the intensive treatment group, as evidenced by their higher scores on the Mini-Mental State Examination (MMSE) and lower scores on functional activity and dementia rating scales, indicating better maintenance of cognitive and daily living skills.
Safety
Intensive treatment proved not only more effective but also safe. Serious adverse events occurred in 35.7% of the intervention group and 38.2% of the control group. Severe side effects, including hospitalizations and deaths, were less frequent in the intervention group. The incidence of falls, fainting, and symptomatic hypotension was similar between groups.
Adjustment for Age, Behavioral, and Metabolic Risk Factors
Even after adjusting for factors such as age, sex, smoking, cardiovascular disease presence, and LDL cholesterol levels, the reduction in dementia and cognitive impairment risk in the intensive treatment group remained significant. The exception was the subgroup with high cardiovascular risk, where intensive treatment had less impact on reducing mild cognitive impairment.
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