Diabetes, high blood pressure cause mental decline

-- People with diabetes and high blood pressure risk not only dying early, but start losing mental abilities in middle age, researchers said Monday.

The study showed it was important to start treating the two conditions, which are both common in the United States and other developed countries, as early as possible, the researchers said.

"Treatment of diabetes and hypertension is important even in middle age, not just in the elderly, for preventing cognitive decline in later life," Dr. David Knopman of the Mayo Clinic in Rochester, Minnesota, who led the study, said in an interview.

Knopman and colleagues tested more than 10,000 people from across the United States who, at first visit, were aged between 47 and 70 years. Six years later they followed up.

"This study showed that diabetes and hypertension were risk factors for losing cognitive function over the six years that we examined people," Knopman said.

They gave the volunteers several tests of mental function. "The ... study measured mental function with three tests -- a test of memory and two tests of mental agility, of doing things against the clock, solving a puzzle of sorts," Knopman said.

"What we saw specifically was actually not that memory declines in people with diabetes and hypertension, but rather that their speed of doing things mentally declined."

Those with either or both conditions were less able to think on their feet, he said.

He said that over the six years the loss was small and the patients themselves would probably not even notice it. But what was striking was how consistent the losses were -- over the whole population the decline was similar and would become noticeable after more than six years.

Knopman said the findings, published in the journal Neurology, supported other work that associates mental decline with diabetes. Smoking and having high cholesterol levels were not linked with the mental declines, the researchers found.

There may be a link to Alzheimer's, he added.

"We feel that the cognitive loss (seen in) diabetes and hypertension might make a person more susceptible to developing Alzheimer's disease in the future," Knopman said. "These things don't cause Alzheimer's disease, but they might make it more likely that a person would get it later in life."

Knopman said it was not clear how the two conditions, which affect millions of Americans, might cause a loss of brain function. An estimated 14 million to 15 million Americans have type-II diabetes, which develops later in life, and as many as 50 million Americans aged 6 and older have high blood pressure.

A survey of 1,000 Americans published on Monday found that 39 percent considered themselves overweight, but only a third considered themselves at risk of developing diabetes. In fact, well over half of all Americans are overweight and being overweight greatly increases the risk of diabetes.

A companion survey of doctors found that 59 percent were most worried about their patients being overweight because of the risk of diabetes.

"These survey results are alarming because they show that Americans are not making the connection between being overweight and developing type-II diabetes," Dr. Steven Heymsfield, deputy director of the New York Obesity Research Center at St. Lukes-Roosevelt Hospital, said in a statement.

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