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SPH prof solidifies link between homocysteine and cognitive problems

Findings show vitamin B12 linked with improved mental performance

A recent study led by School of Public Health epidemiologist Merrill F. Elias shows that high levels of the amino acid homocysteine may be associated with mild cognitive dysfunction in old age.

Homocysteine, a byproduct of the body’s normal cellular metabolism, is believed to increase the risk of heart disease by damaging blood vessels and increasing clotting.

Previous research has suggested that elevated levels of homocysteine may, over time, adversely affect cognitive performance, but until this BU study, no research has clearly linked homocysteine to cognitive functioning. Elias’ research team was able to focus on homocysteine’s effects on cognition by statistically eliminating other factors thought to affect cognitive function.

Drawing participants from the BU-operated Framingham Offspring Study, a spin-off of the landmark NIH epidemiological Framingham Heart Study, the team analyzed data from 2,096 individuals free of dementia. The analysis showed that high levels of homocysteine correlated with decreased performance levels on cognitive tests measuring abstract reasoning, visual and verbal memory, organization, attention, executive ability, and tracking ability.

The investigators discovered an inverse relationship between high blood levels of homocysteine and cognitive performance in persons over age 60, regardless of participants’ sex, education, cardiovascular disease or risk factors for cardiovascular disease, and levels of some vitamins thought to lower homocysteine levels. They did find that the higher the levels of B12 were, the higher the levels of cognitive performance.

For participants under 60, however, the data showed no association between high levels of homocysteine and cognitive dysfunction; the researchers therefore speculate that intake of vitamins B12, B6, and folate early in life — which earlier studies have shown to lower homocysteine levels — may be useful in preserving cognitive function later on.

“We were excited to find this result because it indicates that preventing cognitive difficulties down the road might be something individuals can take charge of well before they reach the age of 60,” says Elias, an SPH adjunct research professor of epidemiology, a School of Medicine adjunct research professor of medicine, and a research professor of mathematics and statistics. “Taking vitamins B12, B6, and folate in the dosages currently recommended by the U.S. Food and Drug Administration could offer a side-effect-free way to prevent difficulties in memory and recall later in life.”

The team’s findings are reported in the current American Journal of Epidemiology.