Inflammation may help explain depression, diabetes link

REUTERS

PublishedJun 9, 2014, 5:04 pm IST

UpdatedJan 10, 2016, 8:38 am IST

Depressed, diabetic patients have higher markers of inflammation in their blood

New York: People with both depression and diabetes have higher markers of inflammation in their blood than those with diabetes alone, a new study suggests.

Researchers have known that people with diabetes have a higher rate of depression than those without the blood sugar disorder. And people with both conditions tend to do worse over the long run than people with diabetes but no depression.

Inflammation is a sign of the body responding to disease, trauma or other stressors. The new study suggests higher inflammation levels may help explain the link between diabetes, depression and worse overall health, researchers said. But it’s still not clear how, exactly.

“We asked, why is depression so bad for diabetes? The study suggests that we have a possible biological explanation,” Dr. Khalida Ismail told Reuters Health.

“Inflammation may be driving a number of different long-term conditions. That’s quite a new way of thinking of the mind and the body,” she said.

Ismail worked on the study at the Institute of Psychiatry at King’s College London in the UK.

She and her colleagues examined 1,227 people with newly diagnosed type 2 diabetes.

Those who reported symptoms of depression tended to be younger and heavier. They also had higher rates of heart and circulation problems and higher concentrations of established markers of inflammation in their blood, according to results published in Diabetes Care.

After the researchers took into account other potential differences between study participants, such as their age, sex, amount of body fat and use of certain medications, six of the 12 inflammatory markers they measured were still linked to depression.

More than one in 20 Americans reported depression in 2005-2006, and about one in 12 has diabetes, a major cause of heart disease and stroke, according to the Centers for Disease Control and Prevention.

Death rates are up to twice as high among people with depression and diabetes as those with diabetes alone, Ismail said.

“The conventional wisdom is that this is a consequence of the psychological burden of having diabetes,” she said. “If that’s the case, if you treat the depression, the diabetes control should improve.”

But it does not, Ismail said. So she began to wonder if inflammation, often seen in people with diabetes, could help explain both conditions and the worse outcomes.

“It’s a bit like an engine,” Ismail said. “You’re running a bit higher. So there’s this constant low-grade inflammation and that’s causing damage to your brain, your pancreas and to your vascular system.”

Dr. Anne Peters said she often sees patients with diabetes, depression and elevated markers for inflammation. But there are still many questions about how they are related.

“The development of depression could in part be triggered by inflammation, but we don’t know what comes first,” she told Reuters Health. “This paper can’t prove causality. The interplay is so complicated.”

Peters directs the University of Southern California Clinical Diabetes Program in Beverly Hills and was not involved in the current study.

“To me, it’s as much a part of diabetes care as looking at blood sugars to screen for and treat depression,” she said.

She believes the best way to begin to combat both depression and diabetes is to eat well and exercise. Her own study found that depression scores among people with diabetes dropped when they were physically active.

“If you exercise, you feel better, your inflammatory markers improve. It’s all about lifestyle interplaying with your health. We’re just living lives we were not made to live. We sit still too much at work. We’re caged up in a way,” she said.

Peters cited a 2012 study that found that people taking antidepressants were at higher risk for diabetes than non-antidepressant users, even after taking their weight into account. The current study did not examine antidepressant use

Genetic test aims to improve diabetes diagnosis

REUTERS

PublishedMar 25, 2016, 9:07 pm IST

UpdatedMar 25, 2016, 9:05 pm IST

Type 1 diabetes occurs when the body's immune system destroys the cells that release insulin.

Radiographer Paul Martin was wrongly diagnosed with type 2 diabetes in April 2013. After months of taking two medications that failed to improve his condition, Martin visited a consultant who subsequently diagnosed him correctly with type 1.

"They put me on tablets - metformin and glycoside - and then I was able to just continue taking those for months until I saw a consultant who then said that my diabetes had got worse. So I was actually diagnosed as type 1 then and introduced to insulin," he explained.

Martin is one of a number of patients diagnosed with the wrong type of diabetes, which differ markedly in causation and treatment. Type 1 diabetes, which accounts for less than ten percent of patients, occurs when the body's immune system destroys the cells that release insulin. Without insulin, patients' bodies cannot absorb sugar. Most type 1 diabetics are diagnosed young.

Type 2 diabetes is often linked with obesity and can be developed at any age. In those cases patients' bodies are unable to use insulin correctly and can suffer damage to their pancreas, although the condition can sometimes be managed through improved diet and weight loss.

Correctly diagnosing which type a patient has is crucial, and in a small minority of cases the wrong diagnosis can be fatal. But in an age of growing obesity in the western world, diagnosis is becoming increasingly difficult for doctors.

According to diabetes expert Dr Richard Oram, from the University of Exeter Medical School, clinical diagnosis is currently based almost entirely on age at diagnosis and whether a patient is obese.

So Oram has come up with a new, relatively inexpensive, genetic test for the disease, which he thinks will help doctors.

"This is a genetic test which essentially means that it measures genetic risk factors for type 1 diabetes and it measures very simply and cheaply in a way that's easy to do, and it means that when a patient presents with diabetes we could measure that genetic risk and if the genetic risk is higher for type 1 diabetes it means they're very likely to have autoimmune type-1 diabetes, and if the genetic risk is low for type 1 diabetes then they're much more likely to have type 2 diabetes, the kind of diabetes associated with obesity," he told Reuters.

Oram's team devised a test which measures 30 genetic variants in DNA and combines all the risks associated with them in a single score, acting as a summary of genetic risk for type 1 diabetes. If a person's score is high they are likely to have type 1 diabetes. If the score is low they may have type 2. A further commonly used test which measures anti-bodies would then be undertaken to complete individual diagnosis.

Oram says early diagnosis is crucial. "If you get this wrong, if you label someone who actually has type 2 diabetes as type 1 they'll be left on insulin for the rest of their life when they don't need it. Even worse, if someone with type 1 diabetes is mislabelled as having type 2 diabetes then they may not be treated with the insulin they need and they may suffer life threatening complications," he said.

A National Institute for Health Research Clinical Lecturer and specialist in Diabetes and Nephrology, Oram says his test will also benefit patients' understanding and attitude towards their condition.

In the short term the University of Exeter Medical School, a leading centre in genome-wide association studies, could test genetic samples sent by patients from hospitals across the UK. Oram's team is also working to develop a bench-side test that any clinical laboratory could run cheaply and quickly.

"If someone could have a blood sample taken it would be sent to our lab here and have the genetic risk score tested," Oram said. "What we think is better for people with diabetes both in the UK and around the rest of the world is if their local hospital could do this test on a bench-side machine."

The research was supported by the UK's National Institute for Health Research (NIHR) and the Wellcome Trust, an independent, global charitable foundation dedicated to improving health. It's also been backed by research charity Diabetes UK.

The latter's regional manager Claire Gordon called the research "excellent." She added: "They're looking at making it a very cheap process, so people can literally have a phone app that will help them determine whether it's type 1 or type 2, and it will be cheap enough that you can do it universally, so one of the problems with lots of research is that things cost a lot of money. This is really great because it identifies what the risk of type 1 and type 2 are and means you're much more likely to get the right diagnosis quickly."

Paul Martin agrees, and says his health has improved markedly since his correct diagnosis two years ago. "Basically my blood sugars have come right down. I don't seem to be as tired as I used to be," he said.

Oram's team published its research in peer-reviewed journal Diabetes Care last November.