Diabetes: Sleep Apnea Increases Risk of Amputation, Blindness In Diabetics

PEOPLE with Type 2 diabetes who have obstructive sleep apnea (OSA) are more at risk of losing their sight due to severe retinopathy, as well as foot problems and possible amputation because of neuropathy, according to new research in the UK.

Retinopathy affects the blood vessels supplying the retina – the seeing part of the eye. Blood vessels in the retina of the eye can become blocked, leaky or grow haphazardly. This damage gets in the way of the light passing through to the retina and if left untreated can damage vision.

Neuropathy is nerve damage and a long term complication of diabetes that can lead to foot ulcers and slow-healing wounds which, if they become infected, can result in amputation.

Obstructive sleep apnea (OSA) is a condition that causes interrupted breathing during sleep. The onset of OSA is most common in people aged 35 to 54 years old, although it can affect people of all ages, including children. The condition often goes undiagnosed. Only one in four people with obstructive sleep apnea are diagnosed with the condition.

(Image courtesy: HealthTree.com)

Dr Iain Frame, Director of Research at Diabetes UK, said: "We already know that there is a high prevalence of OSA in people with Type 2 diabetes. However, this is the first time that the link between OSA and retinopathy and neuropathy in people with Type 2 diabetes has been examined.

This research suggests that if someone with Type 2 diabetes also has this sleeping disorder they are more at risk of developing these serious complications compared to someone with the condition who does not have OSA.

"As being overweight is a risk factor for both OSA and Type 2 diabetes, this is yet another reason to highlight the importance of good weight management through a healthy diet and regular physical activity. In people with Type 2 diabetes, the increasing severity of OSA is associated with poorer blood glucose control and the treatment of sleep disorders (in this case by losing weight) has the potential to improve diabetes control and energy levels."

Researchers from the University of Birmingham looked at 231 people with Type 2 diabetes of whom 149 had OSA, a sleep disorder caused by disturbed breathing. They found there were twice as many people with severe retinopathy (48 percent) in the group with OSA compared to the group without OSA (20 percent). Retinopathy is the leading cause of blindness in the UK's working-age population.

In a separate study, the researchers found that OSA was also linked to neuropathy. They looked at 230 people with Type 2 diabetes of whom 148 had OSA. They found that 60 percent of the group with OSA also had neuropathy compared to 22 percent in the group without OSA.

In both studies, the association between OSA and the two diabetes complications in people with Type 2 diabetes was independent of age, gender, ethnicity, blood pressure, blood glucose levels, smoking and cholesterol.

Dr Abd Tahrani, who led the research, said: "Our work highlights several important issues. Our results emphasized what is already known - that OSA is very common in patients with Type 2 diabetes, much higher than OSA prevalence in the general population.

"Furthermore, our results suggest that OSA is not an innocent bystander in patients with Type 2 diabetes and might contribute to morbidities associated with this condition. Whether OSA treatment has any impact on these complications will need to be determined"

Source: Diabetes UK

Mystery Mechanism Protects Some Diabetics From Developing Complications

WHY are some diabetics free of complications? Researchers are now asking the question the other way around. They want to know why some diabetic patients do not develop complications. What is protecting them? It seems some people with diabetes possess yet-unidentified factors that reduce the risk for and even prevent them from developing diabetes-related complications, despite living with the disease for decades. If researchers can identify the mechanisms protecting these individuals ‒ who are clearly different because something protects them from devastating complications ‒ then it might be possible to develop drugs that can do the same thing.

I had reported end January that what current research provides is an admission that the fundamental mechanisms that create the environment for the development of diabetes complications are still very much unknown.

One aspect of the disease though that is very well documented is the damage that the disease wreaks on an individual’s blood vessels. Diabetes does not kill the individual but the complications often do.

Among the top of the list of complications is cardiovascular disease, as diabetics have three times of the risk compared to non-diabetics. The small blood vessels are also damaged. Nearly 70 percent of patients would have suffered from kidney damage leading to end stage renal failure. Many others suffer from eye complications, with nearly two percent of these diabetics going blind eventually.

Still, despite decades of intensive research on diabetes complications, the fundamental mechanisms are not yet fully known. Neither it is possible to prevent or treat the damage of the blood vessels that affects a majority of all diabetics.

“The blood vessels and other organs of the body are sugar coated and become stiff. It is reminiscent of a premature biological aging,” says Peter Nilsson of the Lund University Diabetes Centre in Sweden who isstudying diabetics with no complications in Sweden.

A just-published study conducted by the Joslin Diabetes Center on people who have lived with type 1 diabetes for more than 50 years presents a strong case for the existence of a protective mechanism in some individuals that allows them to live relatively free of the problems typically associated with long-term duration of diabetes. These mechanisms, the study found, may be different for microvascular (such as kidney, nerve and eye disease) than macrovascular complications (such as heart disease).

A press release issued by the American Diabetes Association yesterday quotes lead researcher George King, Chief Scientific Officer of the Joslin Diabetes Center and Professor of Medicine at Harvard Medical School saying: "If we can identify what constitutes this protective mechanism, we have the potential to induce such protections in others living with diabetes…That's huge."

The Joslin researchers looked at 351 U.S. residents known as the "Medalist" cohort and found that a subgroup of people who had lived with type 1 diabetes for more than 50 years remained free from such complications as proliferative diabetic retinopathy (PDR), a serious eye disease that can lead to blindness (42.6 percent of them); nephropathy, or kidney damage (86.9 percent of them); neuropathy, or nerve damage (39.4 percent); and cardiovascular disease (51.5 percent). Of those who did not develop PDR, 96 percent with no retinopathy progression in the first 17 years of their disease never experienced a worsening of symptoms, meaning that they likely possessed some type of protection specific to this complication.

Surprisingly, glycemic control was not a factor in providing this protective mechanism.

"That doesn't mean of course that glycemic control doesn't help to prevent complications. Numerous other studies have shown that it unquestionably does. In this case, it means only that there is a separate, protective mechanism in play that is not related to glycemic control that also helps to protect against diabetes-related problems. We are still working on identifying just what that is," King said.

It's important to note that most of the people in this study developed type 1 diabetes before strict glycemic control was even possible or used as the standard of medical care, the researchers write. The people in this study likely lived for several decades, therefore, without maintaining strict control.

The study also found that those with high plasma carboxyethyl-lysine and pentosidine, or advanced glycation end products (AGEs), were 7.2 times more likely to have some kind of complication than those who had low levels of this combination of AGEs. (AGEs are compounds that develop in the body after long exposure to high glucose levels and have generally been regarded as playing a role in diabetes-related complications.)

However, those with other types of AGE molecules exhibited protective features. Thus, this study suggests that not all AGEs are alike in their actions and raises the exciting possibility that some AGEs may be markers for protection against one or more diabetic complications.

In an accompanying editorial titled The Question Is, My Dear Watson, Why Did the Dog Not Bark?, Dr. Aaron Vinik, Director, Eastern Virginia Medical School Diabetes Research Center, writes that "the accumulation of AGEs may be one of the important factors in metabolic memory," a phenomenon in which an initial period of good glycemic, lipid and blood pressure control results in a prolonged period of health benefits that last beyond the period of control.

However, while it is clear that for some there is a protective mechanism at play, it's unclear whether metabolic memory is playing a role because glycemic control was not considered important until 1993, long after the study began.

What's most interesting, Vinik points out, is that sRAGE (the circulating soluble receptor for AGEs) is deficient in those who have the most severe complications, and is present at high levels in those with the most longevity. "If this is the missing link, it is huge for the possible emergence of a new biomarker and the potential for therapy that might increase circulating sRAGE or sRAGE itself," he said.

Omega-3s May Fight Diabetic Retinopathy

A healthy intake of omega-3 fatty acids, found in fish and fish oil supplements, has been shown to protect against retinopathy, a leading cause of blindness, particularly among people with diabetes. Now researchers have clarified how fish oil helps.

Previously, researchers from Children's Hospital Boston showed that mice fed a diet rich in omega-3s had less abnormal blood-vessel growth in the retina and less of an inflammatory response compared with mice fed omega-6 fatty acids, a less beneficial fatty acid. In the new study, published Wednesday in the journal Science Translational Medicine, the researchers showed that omega-3s promote healthy blood-vessel growth and inhibit abnormal growth. They found that a specific small molecule in omega-3s was the key to the blood-vessel stabilization.

"Our new findings give us new information on how omega-3s work that makes them an even more promising option," the lead author of the study, Dr. Lois Smith, said in a news release.

In addition, the study revealed that substances called COX enzymes, which are found in aspirin and other pain medications called NSAIDs, don't interfere with the benefits of omega-3s. However, a drug used for asthma, called zileuton, does.

The ability of fish oil to prevent eye problems is of great interest. The federal government is sponsoring a major clinical trial examining the benefits of omega-3 supplements in people with age-related macular degeneration. Smith is exploring the value of omega-3s for premature infants who are susceptible to an eye disease called retinopathy of prematurity.

Diabetics Who Suffer No Complications To Be Studied

What the current research provides is an admission that the fundamental mechanisms that create the environment for the development of diabetes complications are still very much unknown.

When one is diagnosed with diabetes, the patient is prepared to prevent and avoid the complications from the disease. There have been so many studies and research on diabetes complications. Now, researchers are looking at the problem from a different perspective since they have found diabetics who do not develop complications.

Now the question is, why don’t these diabetics develop complications? A new research is now being conducted to find out. This is called the PROLONG study and is focused on the nearly fifteen percent of all diabetics that live life complications free. The study is headed by Valeriya Lyssenko and Peter Nilsson from Lund University Diabetes Center.

What the current research provides is an admission that the fundamental mechanisms that create the environment for the development of diabetes complications are still very much unknown.

One aspect of the disease though that is very well documented is the damage that the disease wreaks on an individual’s blood vessels. Diabetes does not kill the individual but the complications often do. Among the top of the list of complications is cardiovascular disease, as diabetics have three times of the risk compared to non-diabetics. Smaller blood vessels are damaged. Nearly seventy percent of patients would have suffered from kidney damage leading to end stage renal failure. Many others suffer from eye complications with nearly two percent of these diabetics going blind eventually.

“The blood vessels and other organs of the body become sugar coated and stiff. It is reminiscent of premature biological ageing”, says Peter Nilsson.

The pilot study is being conducted in Skåne, Sweden and is projected to study diabetes patients for the next thirty years. They would be comparing complication developments in patients in specific timelines and observe those that do not develop complications during the whole duration.

Participants would be answering inquiries about their lifestyle and how the disease affects them. Also part of the study would be genetic testing, blood sampling and history reviews. The researchers believe that thirty years would be the turning point for a diabetic since the absence of complications beforehand would not develop complications during the remainder of their lives.

“If we can identify factors protecting these individuals from devastating complications, then it might be possible to develop drugs that can do the same thing,” said Valeriya Lyssenko, who will lead the study. “Clearly they are different and we want to find out what it is that protects them.”

Diabetes and Hearing Loss

Diabetics are more than twice as likely as those without the disease to have hearing loss, according to a recent US National Institutes of Health (NIH) study, and which can be fully corrected in 95% of all cases.

Indeed, hearing loss is one of the many problems experienced by diabetics, which are often put down to ‘just getting on a bit’ rather than being linked to their diabetes. Actually Type 2 diabetes and hearing loss have been medically linked for many years, and it is recommended that diabetics should have regular hearing tests as part of their routine screening.

The hearing loss experienced by diabetics has different causes and characteristics from the hearing loss associated with old age. However, many diabetics consult a specialist about the deterioration in their hearing, without mentioning that they are diabetic, so the link is not made.

 

How does diabetes cause hearing loss ? 

There are a number of ways the ears can be affected by diabetes, and hearing loss is frequently the result. Diabetics tend to have a lack of keratin protein which forms a protective layer within the year canal, enabling wax to travel outwards, and preventing over-stimulation of the ear canal tissue. Absence or abnormal level of keratin protein can lead to hearing problems.

Diabetes can also lead to hearing loss as it causes deterioration of the epithelial tissue in the ear canal. This can make the ear canal overly sensitive to the type of plastics commonly used in hearing aids, and can cause yeast, fungus, irritation and infection within the ear, particularly when the air circulation is limited by a hearing aid.

A third link between diabetes and hearing loss, is neuropathy or nerve damage, which is a common complication experienced by diabetics. High blood sugar levels associated with diabetes can cause chemical changes in the body’s nerves that can impair their ability to transmit signals. When this nerve damage occurs in the ear’s neurological system, people can experience problems hearing and understanding speech and also speaking themselves.

 

Is the link between diabetes and hearing loss limited to diabetes type 2 ?

As Type 2 diabetes and hearing loss have been linked in the past, it is usually associated with getting older. However, there is some research that now suggests children with Type 1 diabetes are also likely to experience hearing loss at an early age. The incidence and severity of hearing loss seems to be relative to how long they have had diabetes and how well their glucose levels are controlled.

 

Other symptoms of ‘old age’ can be due to diabetes

Recent research has been looking to see if there is a link between diabetes and hair loss. Again, many diabetics put their hair loss down to getting older, and don’t realise it may be linked to their condition. Hair loss can be caused by a number of factors including the stress on the body of coping with diabetes, and various diabetes related conditions including thyroid problems or PCOS.

Hair loss should reduce when glucose levels are well maintained. Often high blood pressure can be linked to diabetes, and hair loss can be caused by the medication used to treat this. Once the medication is changed or stopped, hair loss should reduce.

In the same way as diabetes and hearing loss, and diabetes and hair loss, deterioration of vision is often accredited to old age rather than diabetes. Diabetics can experience retinopathy which damages the vessels that supply blood to the retina. This can cause a gradual decline in vision.

Laser treatment is very effective in halting this gradual deterioration in vision, and is successful in 80% of cases, but early diagnosis is crucial. Diabetics should have regular eye tests, and get checked out as soon as they believe their sight to be deteriorating, rather than simply assuming it is a symptom of old age.

Courtesy: Sugar Diabetes

Two Therapies May Slow Diabetic Retinopathy in Type 2 Diabetes

In high-risk adults with Type 2 diabetes, researchers have found that two therapies may slow the progression of diabetic retinopathy, an eye disease that is the leading cause of vision loss in diabetics.

Intensive blood-sugar control reduced the progression of diabetic retinopathy, compared with standard blood-sugar control, and combination lipid therapy with a fibrate and statin also reduced disease progression, compared with statin therapy alone. However, intensive blood pressure control provided no additional benefit to patients compared with standard blood pressure control.

Results of the Action to Control Cardiovascular Risk in Diabetes (ACCORD) Eye Study, supported by the National Institutes of Health, recently were published in the New England Journal of Medicine and presented at the 70th Scientific Sessions of the American Diabetes Association.

"This is the largest study to date examining the effects of blood sugar, combination lipid therapy, and blood pressure control on the prevention of diabetic retinopathy progression using retinal photographs," stated Walter Ambrosius, a professor of biostatistical sciences in the Division of Public Health Sciences at Wake Forest University Baptist Medical Center and principal investigator of the ACCORD Eye study's coordinating center, in a July 23 release.

"Many people with diabetes have microvascular problems, which can result in problems with the kidneys and amputation of toes and feet, and the only place that you can directly observe the microvasculature is in the back of the eyes. What we have seen in the eyes is potentially an indicator of what is happening in other parts of the body."

"The ACCORD Eye Study clearly indicates that intensive glycemic control and fibrate treatment added to statin therapy separately reduce the progression of diabetic retinopathy," added Emily Chew, chair of the Eye Study and chief of the Clinical Trials Branch of the Division of Epidemiology and Clinical Applications at the National Eye Institute.

"The main ACCORD findings showed that fibrate treatment added to statin therapy is safe for patients like those involved in the study. However, intensive blood sugar control to near normal glucose levels increased the risk of death and severe low blood sugar, so patients and their doctors must take these potential risks into account when implementing a diabetes treatment plan."

The ACCORD study was a landmark clinical trial that included 10,251 adults with Type 2 diabetes who were at especially high risk for heart attack, stroke or cardiovascular death. The study evaluated three intensive strategies, compared with standard treatments for lowering cardiovascular risks associated with diabetes.

Michael Johnsen/DrugStore News

Diabetic Neuropathy: No Clear Answers

Do high glucose levels cause neuropathy? That's an issue that worries most diabetics. And unfortunately there are no clear answers.

Experts think of blood glucose values as a spectrum of numbers with no clear cutoff between nondiabetic and diabetic. In similar manner, there is a gray area of blood glucose that defines pre-diabetes. Many people use blood sugar and blood glucose interchangeably.

The definition of diabetes has changed over time. The numbers you quote might very well be considered diagnostic of diabetes today whereas they were not 20 years ago. In 1997, the American Diabetes Association definition of normal blood glucose decreased from 120 to 110 mg/dL (6.1 mmol/L). In 2002, the American Diabetes Association defined a normal fasting blood glucose as less than 100 mg/dL (5.6 mmol/L).

Today we consider fasting blood sugars of 100 mg/dl to 125mg/dl to be in the realm of glucose intolerance which is sometimes called pre-diabetes. These patients are at increased risk for developing frank diabetes. Several fasting glucose levels over 125 or a single random glucose over 200 mg are considered diagnostic of diabetes.

There are other tests used to make the diagnosis of pre-diabetes or diabetes. Pre-diabetes is defined as a blood sugar of 140 to 199 mg/dL (7.8 to 11.0 mmol/L) two-hour after drinking 75 grams of an oral glucose solution. The diagnosis of diabetes is confirmed with a blood sugar of 200 mg/dL or greater, two hours after ingestion of the glucose solution.

Hemoglobin A1C is a blood test that gives an estimate of blood sugar levels over the previous three months. Persons with a value of 5.7 to 6.4 percent are thought to have pre-diabetes. Those with a value of 6.5 percent or higher are considered diabetic.

About 30 percent of patients with frank diabetes for more than a decade have some neuropathy. It usually presents as numbness, itching or tingling in the legs but can also be pains. It can even present as digestive problems such as difficulty digesting food or diarrhea due to problems with nerves in the bowels.

Most diabetic neuropathy is caused by peripheral artery disease, in which the small blood vessels are obstructed or partially obstructed and cannot carry oxygenated blood to areas of the body. These areas have pain or other difficulties due to the lack of oxygen.

It is very possible for someone with numbers that are considered pre-diabetes to have some of the complications of diabetes This is especially true of big vessel disease such as myocardial infarction (heart attack), stroke and peripheral vascular disease. Retinopathy, neuropathy and kidney disease are rarer in pre-diabetics but can occur, especially in someone who has pre-diabetes and hypertension (high blood pressure).

The condition of pre-diabetes combined with hypertension is often referred to as the "metabolic syndrome." Elevated cholesterol and triglyceride combined with diabetes and hypertension increases risk of neuropathy even further. Of note, there are some nondiabetics with neuropathy and peripheral vascular disease caused by elevated cholesterol and triglycerides only.

It is prudent that you have a relationship with a physician who will measure not just blood sugar, but cholesterols, triglycerides and blood pressure. He or she may decide that lowering your blood sugars through diet or medication or both might be beneficial for your long-term health. Lowering blood sugar can sometimes even better the pain of diabetic neuropathy.

Many pre-diabetics and diabetic patients are also treated for cholesterol and triglyceride problems and get a baby aspirin daily to decrease risk of heart disease. There are also a number of treatments for pain caused by neuropathy.

In addition to having the above tests, people with pre-diabetes and diabetes should get an annual eye examination to rule out early diabetic retinopathy. Diabetic retinopathy is treatable and is the most common cause of blindness.

It is also prudent to examine the feet for wounds that the patient might not appreciate due to loss of sensation as a part of diabetic neuropathy. Assessment of kidney function and some studies of the heart and vascular system may also be called for.

By the way, there are other causes of peripheral neuropathy. Not uncommon are amyloidosis, which is a disease in which excess protein is deposited in nerve tissue, and vasculitic neuropathy, a rheumatologic disease in which the patient has inflammation near the nerve.

Also we must consider alcoholic neuropathy in someone with an extreme drinking history and even lead poisoning as a possible cause. Patients who have been treated with chemotherapy for cancer and some rheumatologic diseases can also get some painful neuropathies.

Thank you Dr Otis Brawley