Background:
Many genes and environmental factors linked to Alzheimer’s disease (AD) risk affect lipid metabolism or the cardiovascular system, strongly implicating cerebrovascular and metabolic dysfunction in AD pathogenesis. Although some PUFAs may improve cognitive function in aging individuals, it is still unclear how different PUFAs influence AD neuropathology and cognitive function.
Objective:
To examine the influence of polyunsaturated fatty acid (PUFA) metabolism on AD-associated cognitive decline, we investigated the relationship between serum PUFA profile and neuropsychological test performance.
Methods:
Cognitive functioning in patients with probable AD (n = 174, mean age 77.6 years) was examined using the Mini-Mental State Exam (MMSE) and clock drawing test (CDT). Serum samples were obtained for PUFA profile, including the eicosapentaenoic acid/arachidonic acid (EPA/AA) ratio, and measurement of brain natriuretic peptide (BNP) concentration. In the follow-up study, 47 subjects repeated MMSE and CDT after 1 year, According to the second MMSE score, the subjects were divided into the following 2 groups: those with unchanged or improved MMSE score and those with lower MMSE score. A receiver operating characteristic curve was used to evaluate the relationship between the EPA/AA ratio and 1-year cognitive stability.
Results:
In the cross-sectional study, total MMSE score correlated positively with the EPA/AA ratio and systolic blood pressure (SBP), and negatively with age and diastolic blood pressure (DBP) (p < 0.05). In the follow-up study, the MMSE score was lower than baseline in 20 subjects, whereas it was improved or unchanged in 29 patients. The EPA/AA ratio in the stable group was significantly greater than that in the deteriorating group, suggesting an association between higher EPA/AA ratio and cognitive stability over 1 year. The EPA/AA ratio predicted stability of cognitive performance with a sensitivity of 66% and specificity of 70% (odds ratio = 4.43) when the cut-off was 0.67.
Conclusion:
Our results suggest that serum EPA concentration strongly influences cognitive performances in AD patients. The EPA/AA ratio was a sensitive indicator of cognitive stability in this patient group.