Subclinical myocardial injury in midlife, detected by elevated cardiac troponin I levels, was associated with accelerated cognitive decline, smaller gray matter volume and higher incidence of dementia later in life, according to a prospective study published Nov. 6 in EHJ.

Yuntao Chen, PhD, et al., analyzed 5,985 participants from the Whitehall II study, which has followed British Civil Service employees since 1985 to understand more about health and aging. At baseline, participants did not have dementia or cardiovascular disease and cardiac troponin I was measured between ages 45 and 69 years using a high-sensitivity assay. Over a nearly 25-year median follow-up, participants had cognitive testing at six different times and neuroimaging metrics were acquired from MRI scans from 2012 to 2016.

Results showed that 10% of participants were diagnosed with dementia during follow-up. Notably, every doubling of cardiac troponin I was associated with a 10% higher hazard of dementia (95% CI, 3%-17%).

Other findings revealed that participants with higher cardiac troponin I levels at baseline had a faster decline of cognitive function with age. Moreover, those with dementia had higher cardiac troponin I concentrations vs. those without dementia between seven and 25 years preceding their diagnosis.

Importantly, participants with higher cardiac troponin I concentrations (>5.2 ng/L) had a 38% higher risk of dementia (95% CI, 1.09-1.74) vs. those with lower concentrations (<2.5 ng/L) at baseline. Those with higher concentrations also had lower gray matter volume and higher hippocampal atrophy 15 years later, suggesting their brains were equivalent to those of people approximately three years older.

Chen and colleagues write these findings "strengthen the evidence that myocardial injury may directly or indirectly contribute to the etiology of dementia." They suggest that measuring high-sensitivity cardiac troponin I levels in middle age "may be useful in the early identification of a population at risk of cognitive decline and dementia."