New research finds that type 2 diabetics who prefer evening activities and consider themselves night owls are more likely to have symptoms of depression than early birds. This is true regardless of sleep quality. These findings will be presented at the 99th annual meeting of the Endocrine Society in Orlando, Florida this Saturday.
Lead author of the study and associate professor at Mahidol University Faculty of Medicine in Thailand, Dr. Sirimon Reutrakul, notes that this research is important because of the high prevalence of depression in type 2 diabetics. Furthremore, Dr. Reutrakul reminds readers that prior studies have linked untreated depression to poor patient outcomes and compliance with treatment plans, putting them at greater risk of complications.
Past studies on the general public have shown that people with a later chronotype (those who prefer going to bed later and waking up later) were more likely to have symptoms of depression than those with an early chronotype. Dr. Reutrakul and her team decided to look just at type 2 diabetics since they have such a high risk of depression. The goal was to determine whether a later chronotype was directly associated with depression in patients with this chronic condition.
The researchers anticipated that chronotypes would differ depending on geographic location, with those near the equator preferring earlier activities; therefore, they studied two separate groups of diabetic patients in different geographical regions: Thailand and Chicago.
There were 194 patients in the Chicago group, with 70% of them being women. There was a similar group in Thailand, which had 282 patients, 67% of which were women. All respondents were asked to complete questionnaires about depression, preferred times of activity and sleep, and sleep quality. Those in the Chicago group completed the surveys between February and April. Those in Thailand, however, answered questionnaires throughout the entire year to determine if there were any seasonal variations.
In both groups, however, more depression symptoms were reported by those who preferred later activities and sleep than by those who were early to bed and early to rise. This finding was true even after researchers adjusted for age, sex, sleep quality, and other factors that could contribute to depression.
Dr. Reutrakul notes that findings indicate there is a link between cognitive or psychological functioning and the circadian rhythm of those with type 2 diabetes. She did note, however, that there is no evidence of cause and effect, so the association is only modest.
She stated that additional research is necessary to explore different combinations of interventions that may help modify or synchronize the biological clock, such as melatonin and light therapy. Understanding the relationship between the biological clock and depression symptoms presents an opportunity for discovering different treatment strategies that would improve the mental and physical health of diabetes patients.