Changes in the structure and diastolic function of the heart, from early to middle adulthood, may adversely affect cognitive function, according to a new study reported in the journal Neurology.

Researchers analyzed the impact of alterations in structure and function of the heart on cognition over 25 years, from early to middle age, in 2653 subjects from the CARDIA (Coronary Artery Risk Development in Young Adults) study. Fifty-seven percent of participants were women. A baseline echocardiogram was done to measure cardiac function, which was repeated at Years 5, 25 and 30 (participants mean age 30, 50 and 55 years). The parameters evaluated on echo included left ventricular (LV) mass (LVMi); LV systolic function with LV ejection fraction (LVEF); LV diastolic function with left atrial volume (LAVi) and early peak mitral velocity (E)/early peak mitral annular velocity (e’) ratio. 

Results showed an annual increase of 81 g/m2 in the first year and 86 g/m2 in the last year in LV mass. On a similar note, LAVi also showed an increase of 0.42 mL/m2 per year, with average volume of 16 mL/m2 in the first year and 26 mL/m2 in the last year, while an 11% decrease in LVEF was noted.

At year 30 i.e. in the concluding year of the study, the participants underwent cognitive tests to evaluate five cognitive domains - global cognition, processing speed, executive function, delayed verbal memory and verbal fluency. Scores ranged from zero to 30; a score of 26 or more was indicative of representing normal cognition.

After adjusting for variables such as age, sex and education, an increase in LVMi from early to middle life, was found to be associated with lower cognition on most tests. Those who showed a greater than average midlife increase in the weight of the left ventricle exhibited an average score of 22.7, whereas participants in whom the increase in left ventricle weight was less than average had an average score of 24. Increase in left atrial volume over the 25 years of the study was also found to be associated with lower midlife global cognition. Higher LVMi and LAVi in the 30^th year of the study were significantly associated with worse cognition on most cognitive tests. However, no such association was observed for decrease in LVEF.

The traditional cardiovascular risk factors such as type 2 diabetes, hypertension, obesity, dyslipidemia are well-recognised for their adverse effects on cognitive functions. Management of these modifiable risk factors can slow down the process of cognitive decline.

However, this long-term study, which followed participants from early to middle age, has suggested changes in structure and diastolic function of the heart in young adults as potential risk factors for cognitive impairment later on in life. Hence, an echocardiogram can be done to detect even slight abnormalities in the heart structure and functions, even before they manifest clinically. This may identify individuals at higher risk of future cognitive impairment.

Reference

1. Rouch L, et al. Twenty-five–year change in cardiac structure and function and midlife Cognition: The CARDIA Study. Neurology Jan 2022, 10.1212/WNL.0000000000013249; DOI: 10.1212/WNL.0000000000013249.