Up to 20% of adults with type 2 diabetes have severe depression.Each of these disorders is associated with an increased risk of suffering the other, as depression has been linked with greater frequency to high blood glucose figures.Now a study conducted with almost 3,000 people shows that these two diseases, when they occur at the same time, are linked to an early cognitive impairment of the patient.
Between 7% and 9% of Spaniards have type 2 diabetes, although it is suspected that this percentage can reach 12% if those cases that have not yet been diagnosed are taken into account.In recent years, the age of onset of this disorder has descended and now the average is in the 40 years.At the same time, depression reaches a somewhat higher figure of the population, estimated at six million (between 10% and 15%) Spaniards with this psychiatric problem.
The two disorders, both depression and diabetes, have long been associated with an increase in the risk of dementia but so far there were no studies with a good design that could verify this fact.For this reason, researchers from the Department of Behavior Sciences and Psychiatry, from the University of Washington (USA) have wanted to analyze that link in a random and multicenter study in which 52 clinics in the United States and Canada participated.
In total, 2,977 people with type 2 diabetes were evaluated and followed over 40 months, with a high risk of cardiovascular problems and without dementia at the beginning of the study.All of them were performed several tests to assess their cognitive function.Depression symptoms with different specific scales were also evaluated.
When analyzing the data, the researchers verified that those who had been with type 2 diabetes for about nine years and had depression presented a greater and more early cognitive impairment than those who had no depression.
"This is a clear demonstration that depression constitutes a risk factor for cognitive impairment in those with type 2 diabetes. It also demonstrates that this effect is not limited to specific cognitive tests," the authors say in their study, whose datacollects the magazine 'Jama Psychiatry'.
According to the work, the interaction observed takes place in a short period of time and should be monitored to the patient over time.
alteration of different processes
"These results allow us to demonstrate that depression accelerates cognitive deterioration in all aspects: psychomotor speed, verbal learning and executing function. And that effect was independent of previous cardiovascular factors, age, type of treatment for hyperglycemia, tensionarterial and dyslipemia, "says work.
As for the degree of deterioration that these patients present, the data show that in the face of those who do not have depression who do suffer from this disease they double their cognitive decrease.
As the researchers explain in the study, there are several mechanisms that could be responsible for the acceleration of cognitive deterioration in people with diabetes and depression.These patients usually have a bad adhesion to the diet, the exercise, smoke, pay little attention to the medical recommendations, their blood glucose level poorly control and have a high risk of micro and macrovascular complications.Each of these factors contribute to increasing the risk of dementia.
On the other hand, both depression and type 2 diabetes are associated with signs of systematic inflammation, decreased sensitivity to insulin and autonomic dysfunction, which can mediate the effects of depression on the risk of dementia.In addition, depression is also associated with bad regulationof the functions of the hypothalamus, leading to a greater secretion of glucocorticoids and cortisol that can damage the brain areas involved with memory.
