Within the realm of sleep research, the term “sleep disorder” is more common than the term “sleep disturbance”. These two terms are different and should not be used interchangeably. Sleep disorder is diagnosed, using strict criteria, and may be classified into distinct categories, such as insomnia and sleep disorder. The term “sleep disturbance” in the context of diabetes was first mentioned in 1992, mainly used to represent insomnia symptoms, might be universally experienced by anyone at some point in their lives. Sleep disturbance was most commonly characterized by difficulty initiating sleep (DIS), difficulty maintaining sleep (DMS)[24–27], and early morning awakening (EMA).
According to an internet survey of over 7 thousand people in the United States with T2D, three-quarters of participants suffered from sleep symptoms, and one-quarter of them were actually diagnosed with a sleep disorder . A study in Ethiopia showed that about 55.6% of diabetic patients were affected by sleep disturbance . Other research revealed that the prevalence of sleep disturbance in people with T2DM ranged from 55–71% [30, 31]. In this study, the prevalence of DIS, DMS, EMA and any type sleep disturbance was 23.6%, 25.6%, 26.2% and 38.5%, respectively. The finding of this study was lower than studies above maybe due to the different social-cultural backgrounds. In Chinese society, having mental disorders is a shame . Mental diseases, including sleep disturbance, is considered a stigma for many Chinese, which leads to low medical service utilization and treatment . An epidemiological study of 4596 individuals aged 18 years or above living in Beijing, China found that people believed that most members of their society have negative attitudes towards people with mental disorders . Stigma of mental disorders is a barrier and may prevent people seeking [35, 36]. And our study also found that only 32% of patients suffering sleep disturbance received treatment. On the other hand, due to the worry concerns related to drug dependence and side effects, patients often choose non-pharmacological treatments . Acupuncture, as an important component of traditional Chinese medicine (TCM), has been widely applied to treat sleep disturbances. In this study, 15.8% of people in the non- sleep disturbance group used a sleep aid occasionally, including Chinese herbal medicine and acupuncture, to improve their sleep. Maybe that’s why some people did not report their sleep disturbances.
Research revealed that sleep disturbances have a negative impact on glucose metabolism  and there’s a U-shape association between short and long sleep duration in individuals identified as risk factors for developing T2DM [8, 40, 41]. Sleep duration of less than 6 h or > 9 h is associated with increased cardiometabolic risk in people with T2DM . Previous research also found that people with T2DM with approximately 39% sleeping less than 6.5 h per night . In this study, the average sleep time was 5.7 hours in sleep disturbance group and 6.86 hours in non-sleep disturbance group, suggested that shorter sleep time was more closely related to diabetes. In this trial, we also found that incidence of sleep disturbances increases with age, which is consistent with previous studies [44–46].
Depressive symptoms in people with diabetes can have a detrimental impact on engagement with diabetes management, and on glycemic control , as well as on health-related outcomes . Adults with diabetes are more likely to report significant depressive symptoms than those without diabetes . The estimated incidence of clinically significant depressive symptoms among adults with diabetes was 10.6 to 50.6% [49, 50]. And the association between depression and sleep disturbance is close [51, 52]. As such, the high prevalence of this comorbidity is accompanied by high rates of morbidity and mortality worldwide . In this study, depressive symptom in the sleep disturbance group was more obvious than that of those without sleep disturbance, and the more symptoms of sleep disturbance, the more severe depressive symptoms.
Sleep disturbance is one of the factors impairing QOL in people with T2D [54–58], and posing an increased financial burden to both individuals and society [59, 60]. Diabetes and depression can also seriously affect an individual's quality of life . Reports show that the QOL of people with diabetes is lower than that of people without diabetes [28, 62–66]. In this study, we also found that QOL in the sleep disturbance group was worse than that of those without sleep disturbance, and the more symptoms of sleep disturbance, the worse QOL. Our study also found the aging population will have a negative impact on QOL, which is consistent with previous study .