Source: Am J Clin Nutr  |  Posted 9 years ago

Cognitive function variations are associated with B vitamin and homocysteine levels in elderly patients.

Investigators from multiple institutions including the Rowett Research Institute in Aberdeen, United Kingdom, studied living participants from the Scottish Mental Surveys of 1932 (Aberdeen 1921 Birth Cohort) and 1947 (Aberdeen 1936 Birth Cohort).

Fasting blood samples were obtained from the participants, and folate, vitamin B-12 and homocysteine levels were measured. Cognitive performance was assessed by the Mini Mental State Examination (MMSE), the National Adult Reading Test (NART), Raven's Progressive Matrices (RPM), the Auditory Verbal Learning Test (AVLT), the digit symbol (DS) subtest and the block design (BD) subtest.

Results showed that homocysteine levels were higher in the Aberdeen 1921 Birth Cohort compared with the 1936 cohort. Folate and vitamin B-12 were positively correlated while homocysteine was negatively correlated with both folate and vitamin B-12.

The Aberdeen 1936 Birth Cohort had higher MMSE, RPM, AVLT, DS and BD scores compared with the 1921 cohort.

In the 1921 cohort, folate, vitamin B-12 and MMSE scores were positively correlated, homocysteine was negatively correlated with RPM, DS and BD scores, and folic acid was positively correlated with AVLT and DS scores. In the 1936 cohort folate was positively correlated with BD score.

Adjusting for childhood intelligence quotient strengthened the correlation between vitamin B-12 and NART score, strengthened the correlation between homocysteine and RPM score and weakened the correlation between red blood cell folate and DS score.