Psychological Factors, Diabetes & MS
Depression and anxiety have been independently associated with an increased risk of both diabetes mellitus and cardiovascular disease, but the extent to which this risk may be explained by health behaviors, socioeconomic status and biological mediators is still unknown. A study conducted with 2997 men and women supported the hypothesis that depression may increase the risk for diabetes and suggested that the relationship between negative mood states and metabolic variables could extend to the whole population, not only to people diagnosed with either depression or diabetes.
Type 2 diabetes is also closely related to abdominal obesity and is generally associated with other cardiometabolic risk factors, resulting in a high incidence of cardiovascular complications. Most authors consider the links between cardiovascular disease, diabetes and psychiatric disorders bidirectional because patients with anxiety and depression are known to present an elevated cardiovascular risk and patients with Type 2 diabetes and cardiometabolic diseases suffer more frequently from psychiatric problems. However, results from a prospective population-based study (n = 37,291) showed that diabetes could not be considered a predictor of depression or anxiety. Conversely, the presence of these psychological disorders, and particularly the presence of comorbidity between depression and anxiety, have emerged as significant risk factors for onset of Type 2 diabetes independent of other established risk factors for diabetes, such as lifestyle, socioeconomic condition and markers of MS.
In addition to poor glycemic control, hypothalamic–pituitary–adrenal (HPA) axis dysfunction, impaired stress responses and elevated basal levels of glucocorticoids are also hallmark features of experimental models of Type 1 and Type 2 diabetes. Glucocorticoids regulate many functions of the central nervous system, such as the activity and direction of intermediary metabolism, the maintenance of a proper cardiovascular tone and the activity and quality of the immune and inflammatory reaction. Common behavioral and/or somatic complex disorders, such as anxiety, depression, insomnia, chronic pain and fatigue syndromes, obesity, the MS, essential hypertension, diabetes Type 2, atherosclerosis with its cardiovascular sequelae, and osteoporosis, as well as autoimmune inflammatory and allergic disorders, all appear to have a glucocorticoid-regulated component.[21,22]
Conversley, Licht and colleagues found that increases in sympathetic and decreases in parasympathetic activity rather than changes in HPA axis activity are associated with metabolic abnormalities, suggesting autonomic nervous system activity is more strongly associated with MS, than HPA axis activity. Stress and glucocorticoids contribute to the neurological complications observed in diabetes patients and many of the hyperglycemia-mediated changes in the brain are similar to those observed in depressive and chronically stressed patients; common mechanisms may be involved in the development of the neurological complications related to anxiety, depression and diabetes.
Expert Rev Endocrinol Metab. 2012;7(1):63-71. © 2012 Expert Reviews Ltd.