WASHINGTON - People with diabetes and high blood pressure not only risk dying early, but tend to start losing mental abilities in middle age, say neurology researchers.
The study showed it was important to start treating the two conditions as early as possible.
"Treatment of diabetes and hypertension is important
even in middle age, not just in the elderly, for preventing cognitive decline in later life," said Dr David Knopman, of the Mayo Clinic in Rochester, Minnesota, who led the study.
Dr Knopman and colleagues tested more than 10,000 people from across the United States who were aged between 47 and 70.
Six years later, the tests of memory and mental agility were followed up.
"What we saw specifically was 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 quickly, he said.
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.
Dr 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 factors, the researchers found.
But there may be a link to Alzheimer's disease. "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," Dr 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."
Dr Knopman said it was not clear how the two conditions might cause a loss of brain function.
As many as 15 million Americans have type-II diabetes and as many as 50 million Americans have high blood pressure.
He said the study was unusual in that it included more than 2000 African-Americans, who are often not included in medical studies and have an overall higher risk than whites of developing diabetes and high blood pressure.
- REUTERS
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