Controlling Blood Pressure, Cholesterol May Not Boost Brain Health for Diabetics
TUESDAY, Feb. 4, 2014 -- It's well known that having type 2 diabetes can increase a person's chances of impaired memory and thinking. But a new study suggests that intensive treatment of blood pressure and cholesterol levels in people with diabetes won't help lower that risk.
"The finding that intensive blood pressure lowering did not impact [mental] decline in patients with diabetes seems to be consistent with recent trials in patients with diabetes that [showed that] lower is not necessarily better," said one expert, Dr. Kevin Marzo, chief of cardiology at Winthrop-University Hospital in Mineola, N.Y. Marzo was not involved in the new research.
The study, published online Feb. 3 in the journal JAMA Internal Medicine, tracked outcomes for nearly 3,000 people with type 2 diabetes who had no deficits in memory or thinking and showed no other signs of dementia at the beginning of the study.
The patients had taken part in the Action to Control Cardiovascular Risk in Diabetes (ACCORD) trial. Some of them got "intensive" therapy to lower their systolic blood pressure -- the top number in a reading -- to below 120 millimeters of mercury (mm/Hg), while a comparison group got "standard" blood pressure therapy with a goal of lower than 140 mm/Hg.
Other patients in the trial received intensive therapy to battle high cholesterol, which meant adding a fibrate drug to a statin medication to try to bring blood cholesterol levels to below 100 milligrams per deciliter. A comparison group got standard cholesterol treatment -- the statin alone -- plus a placebo.
After more than three years of follow-up, the researchers, led by Dr. Jeff Williamson of the Wake Forest School of Medicine, said they observed no differences in the mental function of people who got intensive therapies versus those who got the standard treatments.
The researchers also looked at the total brain volume of some people in each group, because lessening brain volume has been linked to mental decline.
People in the intensive blood-pressure-lowering group seemed to have less reduction in brain volume than those who got standard blood pressure care, Williamson's team found. Adding the fibrate drug to cholesterol care appeared to have no impact on brain volume, however.
The study authors said there has been a lot of attention given to the possibility that better control of blood pressure and cholesterol might help people with diabetes avoid mental decline.
But although these types of treatments might be helpful for people with heart disease or stroke, the researchers said, the current study showed no overall reduction in the rate of mental decline linked to type 2 diabetes after intensive blood pressure and cholesterol control.
Other experts in diabetes and its relationship to heart health said more research might be necessary, however.
"Diabetes, along with its associated hypertension and cholesterol disorders, can significantly affect the small blood vessels in the brain," said Dr. Valentin Fuster, director of the division of cardiology at Mount Sinai Hospital in New York City. "However, diabetes, hypertension and cholesterol disorders take years to cause effects on the brain."
That means a study that followed patients for only about three years might simply be too short, said Fuster, who is also upcoming editor-in-chief of the Journal of the American College of Cardiology.
"Furthermore, the damage exerted in the brain by diabetes and its associated hypertension and cholesterol disorders may already be irreversible," he said. "If so, one could not expect significant changes with treatment."
Dr. Spyros Mezitis is an endocrinologist and diabetes specialist at Lenox Hill Hospital in New York City. He agreed with Fuster that the Wake Forest findings "may come as a surprise to many physicians who know there is decreased risk for stroke and heart attacks in diabetic patients with intensively controlled hypertension and high cholesterol."
"More studies need to be performed in this area of diabetic research," Mezitis said.
For his part, Marzo said the new study "supports present recommendations that physicians have their diabetic patients live a healthy lifestyle with diet and exercise, control blood pressure to a goal of 140/90 mmHg and treat cholesterol with a statin."
There's more on type 2 diabetes and heart disease at the American Diabetes Association.
Posted: February 2014
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