IPM Take
Brain health policy keeps talking about prevention, but prevention cannot work if the risk factors are invisible. Hypertension and abnormal glycaemia are treatable, measurable and common. Yet this study shows they remain underdiagnosed across African and African diaspora populations, including in the United States. The uncomfortable lesson is that dementia prevention will fail if it stays locked inside neurology. The front line of brain health may be blood pressure cuffs, glucose testing, primary care access and community screening.
Executive Summary
A study published in npj Dementia examined underdiagnosed cardiometabolic risk factors across four cohorts of adults aged 40 and older from Nigeria, Kenya and the United States, including Indianapolis and North Texas. Underdiagnosis was defined as no self-reported diagnosis despite objectively elevated systolic blood pressure or fasting blood glucose.
The findings are striking. Among participants with measured hypertension, underdiagnosis was highest in Ibadan, Nigeria at 67%, followed by Kenya at 53%, North Texas at 28% and Indianapolis at 21%. Underdiagnosis of abnormal glycaemia was even more widespread: 93% in Ibadan, 61% in Kenya, 56% in North Texas and 54% in Indianapolis.
The study also linked elevated fasting glucose with cognitive impairment in Kenya and North Texas. In the North Texas cohort, severe hypertension and diabetes were associated with Alzheimer’s disease-related plasma biomarkers, including pTau217, pTau181, neurofilament light chain and Aβ42/40.
The policy message is clear: cardiometabolic detection should be treated as part of dementia prevention, especially in populations already facing structural diagnostic gaps.
Why it matters
- Policymakers and public authorities: Dementia prevention plans must include systematic blood pressure and glucose detection, not only memory services, awareness campaigns or late-stage care planning.
- Cardiometabolic and neurology clinicians: Hypertension and abnormal glycaemia should be treated as brain-health risks, while cognitive impairment should trigger stronger support for chronic disease detection and self-management.
- Payers and health systems: Funding dementia prevention without funding community cardiometabolic screening is incoherent. Detection, follow-up and treatment continuity must be built into the same pathway.
- Researchers and biomarker leaders: Blood-based Alzheimer’s biomarkers may be harder to interpret in populations where uncontrolled hypertension and diabetes are common and underdiagnosed.
- Patients and advocates: The populations most exposed to dementia risk may also be the least likely to receive early diagnosis of modifiable cardiometabolic disease. Equity in brain health starts before dementia symptoms appear.
Dementia prevention has a blind spot, and it is not hidden deep in the brain.
It is sitting in primary care. In pharmacies. In blood pressure readings never taken. In glucose values never followed up. In communities where cardiometabolic disease is common, treatable and still undiagnosed.
A new npj Dementia study makes that failure visible. Researchers analysed up to 7,000 adults aged 40 and older across four cohorts from Nigeria, Kenya and the United States, focusing on African and African diaspora populations at high risk for Alzheimer’s disease and related dementias. They compared objective cardiometabolic measurements with self-reported diagnoses to identify hidden hypertension and abnormal glycaemia.
The results should worry anyone working on dementia policy.
Among participants with objectively measured hypertension, 67% in Ibadan and 53% in Kenya were underdiagnosed. Underdiagnosis was lower in the US cohorts, but it did not disappear: 21% in Indianapolis and 28% in North Texas. For abnormal glycaemia, the gap was even more brutal. Underdiagnosis reached 93% in Ibadan, 61% in Kenya, 54% in Indianapolis and 56% in North Texas.
This is not just an African health-system story. It is a global warning.
Even in high-income settings, cardiometabolic disease can remain invisible in communities facing structural disadvantage, fragmented care, low trust, weak continuity, poor access, underinsurance or health-literacy barriers. The study’s US findings matter precisely because they show that diagnostic failure is not only about national income. It is also about who health systems are designed to reach.
The brain-health implications are immediate. The 2024 Lancet Commission on dementia identified 14 modifiable risk factors that together account for an estimated 45% of global dementia cases. Cardiometabolic risk sits at the centre of that prevention agenda. Hypertension, diabetes, obesity and physical inactivity are not just cardiovascular issues. They are dementia policy issues.
But a prevention strategy built on “control the risk factors” collapses if the risk factors are never diagnosed.
The npj Dementia study found that elevated fasting glucose was associated with cognitive impairment in Kenya and North Texas. In the North Texas cohort, severe hypertension and diabetes were also associated with Alzheimer’s disease-related plasma biomarkers, including phosphorylated tau, neurofilament light chain and amyloid-related markers. The study does not prove causation, and the authors are careful about that. But it adds a sharp warning: by the time cardiometabolic disease is clinically obvious, biological signals of brain vulnerability may already be present.
That should change how policymakers think about dementia.
Too often, dementia policy begins too late. It starts with memory clinics, specialist diagnosis, caregiver support and long-term care. All of that matters. But if dementia prevention is serious, the policy starting point must move upstream into cardiometabolic detection.
Globally, the scale is enormous. WHO reports that 57 million people were living with dementia in 2021, more than 60% of them in low- and middle-income countries. The Global Burden of Disease dementia forecasting study projected that global dementia cases could rise from 57.4 million in 2019 to 152.8 million by 2050. Meanwhile, hypertension and diabetes remain massive and under-controlled global risks. WHO estimated that 1.4 billion adults aged 30-79 had hypertension in 2024, and that 44% were unaware of their condition. WHO also reports that 14% of adults aged 18 and older were living with diabetes in 2022.
The collision is obvious. Dementia is rising. Cardiometabolic disease is rising. Detection is failing. Yet policy still treats brain health, cardiovascular prevention and diabetes care as separate territories.
That silo is becoming dangerous.
For African populations, the study is especially important because dementia research and biomarker development have historically underrepresented African and African diaspora communities. If diagnostic models, blood-based biomarkers and risk algorithms are developed primarily in populations with better cardiometabolic detection and different social exposures, they may not translate cleanly to settings where hypertension and diabetes are common, untreated and underdiagnosed.
That is not a technical footnote. It is a precision medicine problem.
A blood-based Alzheimer’s biomarker may not mean the same thing in a person living with years of uncontrolled hypertension, untreated diabetes, poverty-related stress and limited access to care. Biomarker interpretation needs context. Otherwise, precision diagnostics could reproduce the same inequities they claim to solve.
The study also challenges genetic fatalism. APOE ε4 is a major dementia risk factor, but the authors found no consistent pattern suggesting that genetic susceptibility reliably translated into better cardiometabolic detection. In plain language: having higher biological risk does not mean the health system will notice you earlier.
That is why the policy response has to be structural.
First, dementia prevention plans should include routine cardiometabolic screening targets. Blood pressure and glucose checks should be embedded in community ageing programmes, primary care, pharmacy services, mobile clinics, memory services and outreach programmes.
Second, screening must come with follow-up. A blood pressure reading without referral, treatment access or continuity is not prevention. It is measurement theatre.
Third, health systems should integrate cardiometabolic and cognitive care. People with cognitive impairment may be less able to recognise symptoms, report diagnoses, manage medications or navigate fragmented services. That means chronic disease pathways need caregiver support, simplified medication plans and proactive follow-up.
Fourth, African and diaspora cohorts must be central to biomarker research, not added later as a diversity paragraph. Data sovereignty, local research capacity and context-specific validation are not optional if global brain-health tools are meant to be globally useful.
Fifth, payers need to fund the boring infrastructure. Blood pressure cuffs, glucose testing, community health workers, pharmacy screening, digital records, referral loops and affordable medicines will not attract the hype of a new Alzheimer’s drug. But they may prevent more disease.
This is the political tension at the centre of dementia prevention. The world is investing heavily in high-tech diagnostics and disease-modifying therapies. Yet millions of people remain exposed to undiagnosed hypertension and abnormal glycaemia, two measurable risks sitting in plain sight.
That imbalance is not scientific. It is political.
The future of brain health will not be decided only in neurology clinics. It will be decided in whether public health systems can detect and manage cardiometabolic disease early, equitably and continuously.
Dementia prevention cannot begin after memory fails.
It has to begin when blood pressure and glucose are still modifiable.
