Diabetes Articles

Diabetes Articles.

Link Between Diabetes and Alzheimer’s Deepens

Several new studies suggest that diabetes increases the risk of Alzheimer’s disease, adding to a store of evidence that links the disorders. The studies involve only Type 2 diabetes, the most common kind, which is usually related to obesity.

The connection raises an ominous prospect: that increases in diabetes, a major concern in the United States and worldwide, may worsen the rising toll from Alzheimer’s. The findings also add dementia to the cloud of threats that already hang over people with diabetes, including heart disease, strokes, kidney failure, blindness and amputations.

But some of the studies also hint that measures to prevent or control diabetes may lower the dementia risk, and that certain diabetes drugs should be tested to find whether they can help Alzheimer’s patients, even those without diabetes. Current treatments for Alzheimer’s can provide only a modest improvement in symptoms and cannot stop the progression of the disease.

The new findings were presented yesterday by the Alzheimer’s Association at a six-day conference in Madrid attended by 5,000 researchers from around the world.

Alzheimer’s affects 1 in 10 people over age 65, and nearly half of people over 85. About 4.5 million Americans have it, and taking care of them costs $100 billion a year, according to the association. The number of patients is expected to grow, possibly reaching 11.3 million to 16 million by 2050, the association said.

But those projections do not include a possible increase from diabetes.

“Alzheimer’s is going to swamp the health care system,” said Dr. John C. Morris, a neurology professor at Washington University in St. Louis and an adviser to the Alzheimer’s Association.

Not everyone with diabetes gets Alzheimer’s, and not all Alzheimer’s patients are diabetic. But in the past decade, several large studies have found that compared with healthy people of the same age and sex, those with Type 2 diabetes are twice as likely to develop Alzheimer’s. The reason is not known, but researchers initially suspected that cardiovascular problems caused by diabetes might contribute to dementia by blocking blood flow to the brain or causing strokes.

More recently, though, scientists have begun to think that the diseases are connected in other ways as well. In both, destructive deposits of amyloid, a type of protein, build up: in the brain in Alzheimer’s, in the pancreas in Type 2 diabetes.

People with Type 2 often have a condition called insulin resistance, in which their cells cannot properly use insulin, the hormone needed to help glucose leave the blood and enter cells that need it. To compensate, the pancreas makes extra insulin, which can reach high levels in the blood. Too much insulin may lead to inflammation, which can contribute to damage in the brain.

In addition, abnormalities in glucose metabolism and insulin levels in the brain itself may be harmful. Some research has found that too much insulin in the brain can contribute to amyloid buildup. Researchers have even suggested that Alzheimer’s disease may actually be “Type 3 diabetes,” a form of the disease affecting the nervous system.

About 20 million people in the United States have Type 2 diabetes. The number has doubled in the past two decades. An additional 41 million are “prediabetic,” with blood sugar rising toward the diabetic level. Diabetes rates are expected to increase because rates of obesity are rising, and epidemiologists predict that one in three American children born in 2000 will eventually develop Type 2 diabetes.

Worldwide, diabetes is also on the rise, increasing to 230 million cases from 30 million in the past 20 years.

One of the new studies found that even people who had borderline diabetes were 70 percent more likely than those with normal blood sugar to develop Alzheimer’s. The study, by researchers from the Karolinska Institute in Sweden and the Stockholm Gerontology Research Center, included 1,173 people 75 and older.

The incidence of dementia was highest in borderline diabetics who also had high blood pressure. But the higher risk occurred only in those who did not carry the gene apo E4, which is associated with some cases of Alzheimer’s.

The director of the study, Dr. Weili Xu, said that since increased exercise and changes in diet can reverse borderline diabetes, they may also help ward off dementia.

Another study found that in people with diabetes, the higher their blood sugar, the greater the risk of dementia. Higher levels of blood sugar mean the diabetes is severe or is being poorly treated, or both.

The study, led by Rachel A. Whitmer of the Division of Research at Kaiser Permanente in Oakland, Calif., was based on the records of 22,852 patients with Type 2 diabetes who were followed for eight years.

Initially, none had dementia. The researchers looked at glycosylated hemoglobin, a blood test that reflects blood sugar levels for the previous two months. Normal is 7 or lower. Here, the risk of dementia rose when the level reached 10. Those with readings from 10 to 11.9 had 13 percent more risk than people with levels below 10. From 12 to 14.9, the risk was 24 percent higher. Over 15, it jumped to 83 percent higher.

In an interview, Dr. Whitmer said one implication of the study was that tight control of blood sugar was important in elderly patients, even though some doctors tended to relax the rules for them.

“Tight control is important for the whole life span,” Dr. Whitmer said. “The older you are, the more likely you are to get dementia.”

She added: “With the whole diabetes epidemic we’re seeing much more Type 2, so are we going to see even more Alzheimer’s than we thought we would see? If we continue in this direction, it’s a little bit frightening.”

Another study suggested that a certain class of diabetes drug, commonly called a glitazone, might lower the risk of Alzheimer’s in people with diabetes. Pilot studies in small groups of patients have hinted that the drugs may be of some help, and the National Institute on Aging is sponsoring research in this area.

In the study, researchers used the records of 142,328 patients in the Veterans Affairs system who did not have dementia but were just starting to take a glitazone or insulin. They tracked the patients for six years. Compared with those using insulin, among the patients who took pioglitazone (Actos) or rosiglitazone (Avandia), there were nearly 20 percent fewer cases of Alzheimer’s. The glitazones had a similar advantage over another diabetes drug, metformin.

Glitazones lower blood sugar by helping the body to use insulin more efficiently, so that less insulin is needed. The drugs may also lower inflammation.

Though the results sound like good news for patients, the director of the study, Donald R. Miller, an epidemiologist at Boston University and at the Department of Veterans Affairs, cautioned that the findings were not conclusive and that they did not mean that people should start taking the drugs to ward off Alzheimer’s.

“This is preliminary, the first study of its kind,” Dr. Miller said, emphasizing that more studies were needed to verify his results.

GlaxoSmithKline, the maker of rosiglitazone, sponsored the study but did not control the way it was done or interpreted, Dr. Miller said.

Another study, a small one with only 25 patients, tested pioglitazone for 18 months in nondiabetic people with Alzheimer’s to see if it was safe and showed signs of slowing the disease.

The drug did seem safe, causing only some foot and ankle swelling. But compared with people taking placebos, patients taking the drug showed no statistically significant differences in memory, thinking, daily function or abnormal behavior.

But there were hints that some measures worsened less in the patients on the drug, and the researchers, led by Dr. David S. Geldmacher of the University of Virginia, said it deserved further study in Alzheimer’s. The study was sponsored by the drug’s maker, Takeda.

by Denise Grady at The New York Times.

DIABETES ARTICLES.

Study of Children With Diabetes Suggests Obesity Is Affecting Life Expectancy

Children who get obesity-related diabetes face a much higher risk of kidney failure and death by middle age than people who develop diabetes as adults, a study suggests. The research, in The Journal of the American Medical Association, lends support to warnings obesity-related ills are on the verge of shortening the average life span in the United States. The study involved Pima Indians in Arizona. Of the 1,865 participants with Type 2 diabetes, 96 developed it in childhood. During at least 15 years of follow-up, 15 of them, or 16 percent, developed end-stage kidney failure or died from diabetic kidney disease by age 55. That compared with 133, or 8 percent, of those who developed diabetes after age 20.

Diabetes Articles.

Carbohydrate Diet for Diabetics

Since the early 1960's, studies have hinted that the traditional advice to diabetics to eat lots of protein and very few carbohydrates may not be the wisest approach. Such a diet is likely to be rich in cholesterol-raising fats, which would further increase the diabetic's already high risk of developing atherosclerotic heart disease.

Now, several recent studies have clearly shown that the traditional high-protein, low-carbohydrate diet is much less effective in controlling diabetes than a diet rich in fibercontaining complex carbohydrates. In the latest such study, published in the Jan. 3 issue of The Lancet, a leading British medical journal, researchers found that a diet containing large amounts of beans, whole-grain bread, vegetables and fruits ''improves all aspects of diabetic control,'' including how high the blood sugar rises immediately after eating.

The research team, from Oxford University, concluded on the basis of their studies that ''continued use of a low carbohydrate diet no longer appears justified.'' Similar conclusions have been reached by Dr. James W. Anderson of the University of Kentucky, who has been able to reduce and sometimes eliminate the need for insulin in diabetics who follow his high-fiber, high-carbohydrate diet.

In the British experimental diet, most of the protein was derived from legumes, such as kidney beans and butter beans, which are rich in dietary fiber as well as complex carbohydrates (starches). The researchers said the high-bean diet, when introduced slowly, produced little abdominal discomfort, but they predicted that most people would eventually find the menu monotonous. The researchers are now examining modified versions that may be equally effective and more acceptable as lifelong diets. A Voyage to Uranus

The National Aeronautics and Space Administration has approved a plan to continue Voyager 2 on a trajectory that would take it to Uranus in 1986 after flying past Saturn this August.

Under the plan, the spacecraft should fly within 66,000 miles of Uranus Jan. 24, 1986, making measurements and taking pictures as it races by and heads for a possible encounter later with Neptune. Uranus, the seventh planet out from the Sun, is twice as far from the Sun as Saturn.

The decision to aim Voyager 2 for Uranus was reached by NASA officials after it was determined that Voyager 1 had achieved all its scientific objectives in flying by Saturn and its moons last November. By continuing on a Uranus-bound trajectory, Voyager 2 will not be able to make a close reconnaissance of Saturn's largest moon, Titan, but will still return thousands of high-resolution pictures of Saturn and several of its other moons. Mussels Have Problems Too

To all appearances, mussels enjoy a serene lifestyle and have no cares in their marine world. But scientists have discovered that life can be hard for the placid grayish-brown creatures that are usually found clustered on tide-pool rocks or on wooden pier pilings. In fact, life can be so tough that mussels, as well as other fish, are showing signs of stress, a byproduct of modern industrialization.

Dr. Florence Harrison, a marine biologist at the University of California's Lawrence Livermore National Laboratory, together with four co-workers has found that chemicals and heavy metals that flow to the sea from the nation's industrial centers are the culprits. They cause biological stress symptoms ranging from a shortened life span to stunted growth, decreased reproduction and increased susceptibility to disease.

The pollutants the biologists are studying include hydrocarbons from oil spills, discharges from coal and oil-burning plants and such metals as copper in effluents from sewage and power plants. The research was conducted in a marine laboratory by raising common bay mussels and segmented worms that live in the ocean floor and exposing them to pollutants found in the environment.

The project is part of a United States Environmental Protection Agency project called ''Musselwatch'' that studies mussel populations around the world, enabling scientists to keep an eye on the health of shoreline areas by monitoring the health of the animals and their exposure to pollutants. The studies are funded by the E.P.A. and the Federal Department of Energy.

from New York Times