People showing signs of heart damage in middle age are more likely to develop dementia later in life, according to new research led by University College London (UCL).
The study, published in the European Heart Journal and funded by the British Heart Foundation, found that middle-aged adults with higher blood levels of cardiac troponin I were significantly more likely to develop dementia in the following decades. Elevated troponin levels were detectable as early as 25 years before dementia diagnosis.
While doctors typically test for very high troponin levels when diagnosing heart attacks, even modest elevations can indicate silent or ongoing heart muscle injury. Such damage may affect blood vessel health and blood flow to the brain, increasing dementia risk.
Poor heart health in midlife puts people at greater risk of dementia later in life. Brain damage in dementia develops slowly, often over decades. Managing shared risk factors, such as high blood pressure, could slow or even prevent both dementia and cardiovascular disease.
Further research is needed to determine how accurately troponin can predict future dementia risk, but protein could eventually form part of a predictive risk score.
Dementia encompasses a range of conditions that cause damage to brain cells, resulting in memory loss, cognitive decline, and impaired reasoning. The 2024 Lancet Commission on Dementia estimated that up to 17% of dementia cases could be prevented or delayed by improving cardiovascular risk factors such as high blood pressure, cholesterol, inactivity, and obesity.
The current research drew on data from nearly 6,000 participants in the long-running Whitehall II study, which has tracked British civil servants since 1985 to explore ageing and health. Participants, aged 45 to 69 at the time, had high-sensitivity troponin tests, which can detect minute elevations far below those seen in heart attacks. None had dementia or cardiovascular disease at baseline.
Over an average 25-year follow-up, 695 participants developed dementia. Those individuals consistently had higher midlife troponin levels, sometimes decades before their diagnosis, than matched controls. Participants with the highest troponin levels at the outset faced a 38% greater risk of developing dementia by the study’s end.
After accounting for factors such as sex, ethnicity, and education, the researchers found that higher troponin levels were associated with faster cognitive decline. At age 80, individuals with elevated troponin performed like peers 1.5 years older; by age 90, the gap widened to around two years.
Brain scans of a subset of 641 participants reinforced these findings. Those with the highest midlife troponin levels had smaller hippocampal volumes and reduced grey matter, suggesting brains equivalent to those of people roughly three years older.
This is the longest study to date linking raised cardiac troponin to cognitive decline and dementia. These results suggest that troponin levels in midlife may be a particularly useful biomarker for predicting dementia risk.
Heart and brain health are inseparable. Middle age appears to be a particularly critical window, with damage at this stage setting a long-term trajectory of decline. Protecting heart health, through blood pressure control, cholesterol management, physical activity, healthy weight, and avoiding smoking, also gives the human brain the best chance to age well.
Source: University College London
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