Type 2 Diabetes, Sleep Disorders Both Linked to Increased Risk of Depression

Both type 2 diabetes and sleep disorders were seen as independent risk factors for depression, according to new research.

A team, led by Ida Kim Wium-Andersen, Psychiatric Center Copenhagen, examined the influence of comorbid sleep disorder on the link between type 2 diabetes and the risk of incident depression.

In the study, the investigators identified 232,489 patients, all of which registered aged of at least 40 years with a type 2 diabetes diagnosis between 2000-2012 in the Danish National Diabetes Register. There was also a matched reference population included in the study.

Analyzing the Risk of Depression

The investigators estimated the risk of incidence depression following a type 2 diabetes diagnosis and possible effect modification of comorbid sleep disorder using adjusted Cox proportional hazards regression.

The team defined sleep disorders as a diagnosis of insomnia, hypersomnia, or sleep-wake schedule disorders or the use of sleep medication including z-drugs or melatonin.

At baseline, 15.3% of participants in the study had a sleep disorder. However, during follow-up, 2.6% of the patients were diagnosed with depression, while 32.1% were treated with antidepressants.

Hazard Ratios

This resulted in an unadjusted hazard ratio for depression of 1.54 (95% CI, 1.52–1.56) for patients with diabetes. This attenuated to 1.50 1.50 (95% CI, 1.48–1.52) after adjustment for sleep disorders, which further attenuated to 1.27 (95% CI, 1.26–1.29) in the model further adjusted for psychiatric and somatic comorbidities.

An analysis of type 2 diabetes and sleep disorders as independent and combined variables compared to none of the conditions on the risk of depression, showed a HR of 1.27 (95 % CI, 1.19–1.35) for type 2 diabetes without sleep disorder, 1.46 (95 % CI, 1.33–1.59) for sleep disorders without type 2 diabetes, and 1.49 (95% CI, 1.37–1.63) for both conditions.

“[Type 2 diabetes] and sleep disorders were independently associated with subsequent risk of depression and individuals with both conditions experienced the greatest relative risk,” the authors wrote. “Sleep disorders neither explained nor amplified the relation between diabetes and depression.”

Sleep Duration and Metabolic Disease

Earlier this year, investigators found less than 7 hours of sleep can be damaging for women as it increases the likelihood of developing metabolic diseases like diabetes and hypertension.

A team, led by Lili Huang, School of Public Health, Shanghai Jiao Tong University School of Medicine, identified the association between short and long sleep duration and the risk of metabolic diseases.

Female participants with less than 7 hours of sleep per day had an increased value of LAP and TyG by 25.232% (95% CI, 10.738-41.623%) and 0.104 (95%CI, 0.024-0.185), respectively, in the crude model compared to females who sleep between 7-9 hours per day.

The effects were lessened, but still significant for LAP (11.405%; 95% CI, 1.613-22.262%).

The results of the logistic regression models were similar to the results of the linear regression models.

Here the investigators found less than 7 hours of sleep per day could increase the risk of elevated LAP (OR, 1.725; 95% CI, 1.042-2.856) after adjusting for multiple covariates.

The study, “Diabetes, sleep disorders and risk of depression - A Danish register-based cohort study,” was published online in the Journal of Diabetes and its Complications.