Diabetes May Be Caused By Depression

While it is common knowledge that having a chronic disease increases chances of depression in patients, here is evidence that indicates depression could also be a factor in causing chronic diseases such as diabetes.

A paper published in Diabetes Technology and Therapeutics, 2010, from Chennai showed higher levels of depression among those newly detected with diabetes and those with impaired glucose tolerance, as against those who had normal blood sugar levels.

Authored by S. Poongothai of Madras Diabetes Research Foundation, based in Chennai in south India, as part of a series of articles she worked on for her Ph.D, the paper is significant in that the tests were done in the community and the depression noted before blood sugar tests were done.

Co-author V. Mohan, who heads Dr. Mohan's Diabetes Specialities Centre, says, “What this article flags off is the idea that depression itself may be a likely cause of diabetes.”

The subjects for the study were recruited from the Chennai Urban Rural Epidemiological Study. Of the total of over 23,000 persons tested, there were 1218 people with newly- detected Diabetes (NDD), 7,657 with impaired fasting glucose (IFG); and 14, 912 with normal fasting glucose (NFG).

While the overall prevalence of depression was 14.3 per cent, an increasing prevalence was seen with increasing grades of glucose tolerance: NFG (13.1 per cent), IFG (15.7 per cent) and NDD (19.7 per cent), being higher among women at all grades.

Depression can increase the risk of diabetes due to increased levels of counter-regulatory hormones, which can lead to obesity, insulin resistance and glucose intolerance, Dr. Poonothai says in the paper. “The lesson in this is that not only should we treat diabetics for depression, but that by treating depression, the person may actually be able to side-step diabetes,” Dr. Mohan explains.

His recommendation is also that everyone with depression must be screened for diabetes as well.

WHO Formally Accepts HbA1c Test for Diabetes Diagnosis

The World Health Organisation (WHO) has formally accepted the use of the HbA1c test for the diagnosis of diabetes, rather than the more common method of taking a blood sample and checking it for glucose content.WHO have assessed the HbA1c test as a way of measuring how much glucose is being carried by the red blood cells in the body and shows a person’s levels of blood glucose for the previous two or three months.

The HbA1c test is an easier test for diagnosing, as the use of blood samples meant people sometimes had to fast and then consume a high glucose drink, with blood being taken before and after and the levels of glucose compared.

WHO have stated that the HbA1c test, although more costly, does provide a more practical and easier technique for diagnosing the metabolic condition, but warned that rigorous qualityassurance tests must be put in place and measurements standardised.

Ala Alwan, assistant director general of the Non-communicable Diseases and Mental Health Cluster at WHO, commented "Unlike other means of diagnosis, it does not require a patient to fast before a blood sample is taken, nor to consume a glucose drink that many people find unpalatable. HbA1c also has the advantage of reflecting the person’s average blood glucose levelsover the preceding two–three months."

Simon O’Neill, director of care, information and advocacy, at charity Diabetes UK, also said "This recommendation does not mean other tests for diagnosing diabetes will be shelved. Doctors will continue to use their clinical judgement about which test is most appropriate for their patients on an individual basis."

Diabetes Can Cause A Sugar Coating That Smothers Body's Immune Defences

Research led by the Warwick Medical School at the University of Warwick has found that unhealthy glucose levels in patients with diabetes can cause significantly more problems for the body than just the well-known symptoms of the disease such as kidney damage and circulation problems. The raised glucose can also form what can be described as a sugar coating that can effectively smother and block the mechanisms our bodies use to detect and fight bacterial and fungal infections.

In diabetes, patients suffer a higher risk of chronic bacterial and fungal infections but until now little has been known about the mechanisms involved. Now new research led by Dr Daniel Mitchell at the University of Warwick's Warwick Medical School has found a novel relationship between high glucose and the immune system in humans.

The researchers have found that specialized receptors that recognize molecules associated with bacteria and fungi become "blind" when glucose levels rise above healthy levels. The new research may also help explain why diabetic complications can also include increased risk of viral infections such as influenza, and also inflammatory conditions such as cardiovascular disease.

The researchers looked at the similarities in chemical structure between glucose in blood and body fluids, and two other sugar called mannose and fucose. These sugars are found on the surfaces of bacteria and fungi and act as targets for receptors in our body that have evolved to detect and bind to microbial sugars to then combat the infection.

The research found that high levels of glucose outcompetes the binding of mannose and fucose to the specialized immune receptors, potentially blocking these receptors from detecting infectious bacteria and fungi. Glucose also binds in such a way that it inhibits the chemical processes that would normally then follow to combat infections. If this happens it can inhibit a range of key processes including:

• It can inhibit the function of immune system receptors called C-type lectins such as MBL (Mannose-binding lectin) which are known to bind to a sugar known as mannose that is present in the structure of infectious fungal bacterial cell walls. Unlike glucose, mannose does not exist in mammals as a free sugar in the blood.
• The loss of MBL function may also predispose the body to chronic inflammatory diseases, since MBL is involved in the processing and clearance of apoptotic cells (dying cells).
• A number of C-type lectins tat can be affected by raised glucose levels, including MBL, but also including immune cell surface receptors DC-SIGN and DC-SIGNR, are found in key parts of our circulation and vascular system such as plasma, monocytes, platelets and endothelial cells that line blood vessels. Inhibiting the function of these key molecules in those settings could contribute to diabetic cardiovascular and renal complications.

Warwick Medical School researcher Dr Daniel Mitchell said: "Our findings offer a new perspective on how high glucose can potentially affect immunity and thus exert a negative impact on health. It also helps to emphasize the importance of good diet on preventing or controlling diseases such as diabetes. We will build on these ideas in order to consolidate the disease model and to investigate new routes to treatment and prevention."

Provided by University of Warwick