People given intensive help to reduce their high blood pressure such as medication and coaching have a lower risk of dementia, researchers have found.
According to the World Health Organization, 57 million people around the world had dementia in 2021.
However, experts have long stressed dementia is not an inevitable consequence of ageing. Researchers found about half of cases could be prevented or delayed by addressing 14 risk factors including hearing impairment, smoking, obesity, excessive alcohol consumption and social isolation – as well as high blood pressure.
Now researchers say tackling the last of these could reduce the risk of dementia by 15%.
“Antihypertensive treatment can prevent dementia in patients with uncontrolled hypertension,” said Prof Jiang He, the co-author of the study, from the University of Texas Southwestern Medical Center. “Given the high prevalence of uncontrolled hypertension worldwide, this effective intervention should be widely adopted and scaled up to reduce the global burden of dementia.”
Writing in the journal Nature Medicine, the researchers in China and the US reported how the trial involved 33,995 people aged 40 years and over with uncontrolled high blood pressure, spread across 326 villages in rural China.
The team randomly selected 163 of these villages, with the 17,407 participants who lived there given intensive blood pressure management from non-physician community healthcare providers, often called “village doctors”.
This included free or cheap medications to lower blood pressure, given at tailored doses, health coaching to help them stick to medications and lifestyle modifications – such as weight loss, alcohol reduction and reducing salt intake – and equipment and instructions to monitor blood pressure at home.
The other 163 villages – encompassing 16,588 participants – received “usual care” – meaning participants’ blood pressure was managed in their normal clinical settings. While lifestyle changes were recommended and some took blood pressure-lowering drugs, this group did not receive free at-home blood pressure monitors or medications, or coaching.
When the researchers followed up with the participants after four years, they found 668 of those in the intensive blood pressure management group had dementia, compared with 734 in the usual care group – with analyses suggesting the former group had a 15% lower risk of dementia. Further work revealed this group had a 16% lower risk of cognitive impairment without dementia.
While the team noted that the cognitive function of participants was not assessed at the start of the study, they said the similarity of participants in the two groups means this is unlikely to skew the findings.
However, Prof Joanna Wardlaw, of the University of Edinburgh, who was not involved in the work, said the study could not unpick the relative contribution of optimal blood-pressure control and lifestyle changes on the reduction in dementia risk, suggesting the results reflected a combined effect.
Others said similar research should now be carried out with longer follow-up periods, and added that the approach also needed to be trialled in other countries.
Prof Tara Spires-Jones, the director of the Centre for Discovery Brain Sciences at the University of Edinburgh, said the research “provides further strong evidence supporting the importance of managing blood pressure and other cardiovascular risks to protect the brain during ageing”.
But, she added: “It is important to note that treating high blood pressure was not a foolproof guarantee as some people receiving treatment still developed dementia.”
