Metabolic Syndrome and Dementia in Older People

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Yaffe K, Kanaya A, Lindquist K, et al.: The metabolic syndrome, inflammation, and risk of cognitive decline. JAMA 292:2237-2242, 2004.

What is the problem and what is known about it so far?

Metabolic syndrome -- a group of signs that include a large waist, high fats in the blood, high blood pressure, and poor control of blood glucose -- increases the risk of a person getting heart disease. Some studies have linked disease of the heart and blood vessels to dementia (lowered mental ability).

Why did the researchers do this particular study?

The researchers wanted to find a link between metabolic syndrome and lowered mental ability.

Who was studied?

A total of 2,632 white and African American people were studied between 1997 and 2002. All participants were between 70 and 79 years old.

How was the study done?

The researchers used a well-known test to assess memory, concentration, and other factors of mental abilities. They tested for metabolic syndrome by measuring waist size, levels of fat in the blood, blood pressure, and fasting blood glucose levels (taken before participants ate ). The researchers also took blood samples to find out if study members showed any signs of inflammation (cell injury).

What did the researchers find?

The researchers found that about 1,000 participants had metabolic syndrome and were more likely to be white, female, and smokers. They also were more likely to have already had a heart attack and to show signs of cell injury.

Participants with metabolic syndrome more were likely to have lowered mental ability than those without metabolic syndrome.

What were the limitations of the study?

Some study members may have shown a risk for or signs of lowered mental ability from causes other than metabolic syndrome -- such as disease of their small blood vessels or Alzheimer's disease. This could change the results of the study.

Also, most of the participants functioned well and were in otherwise good health. Other studies need to be done on people who already have some signs of lowered mental ability to see if the study results are similar.

What are the implications of the study?

It would be helpful to find out if preventing metabolic syndrome or reducing inflammation would lower the risk of lowered mental ability.