Methods for identifying pre-disposition to cognitive decline and agents for reducing or preventing cognitive decline, or improving cognitive ability

A method for identifying pre-disposition to cognitive decline in a subject, the method comprising:

• calculating a Nutritional Risk Index (NRI) of the subject, wherein the calculating the NRI of the subject comprises:
• (a) obtaining an erythrocyte sample from the subject and determining a level of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) in the erythrocyte sample, wherein the level of EPA and DHA of less than or equal to about 4.82 weight percent of total fatty acids in the erythrocyte sample from the subject is assigned a score of n, and the level of EPA and DHA of more than about 4.82 weight percent of total fatty acids in the erythrocyte sample from the subject is assigned a score of zero;
• (b) obtaining a serum sample from the subject and determining a level of 25-hydroxyvitamin D in the serum sample, wherein the level of 25-hydroxyvitamin D in the serum sample from the subject that is less than or equal to about 15 ng/ml is assigned a score of n, and the level of 25-hydroxyvitamin D in the serum sample from the subject that is more than about 15 ng/ml is assigned a score of zero;
• and
• (c) obtaining a plasma sample from the subject and determining a level of homocysteine in the plasma sample, wherein the level of homocysteine in the plasma sample from the subject that greater than or equal to about 18.1 μmol/L is assigned a score of n, and the level of homocysteine in the plasma sample from the subject that is lower than about 18.1 μmol/L is assigned a score of zero,
• wherein n is a positive integer,
• wherein the NRI of the subject is calculated as the sum of scores obtained from steps (a), (b) and/or (c), and
• an NRI score greater than zero is indicative of pre-disposition to cognitive decline of the subject.