Summary: Prolonged sleep deprivation (<7 hours) has been linked to a variety of health risks, including an increased risk of type 2 diabetes (T2D). Previous studies have shown that sleeping less than 7 hours per day is 1.09 times more likely to develop T2D. Here, we share a cohort study [1] to explore the association between individuals' self-reported short sleep duration and the incidence of T2D, and to observe the effect of dietary type on the risk of T2D morbidity. The results showed that short habitual sleep was significantly associated with an increased risk of T2D, while individuals who maintained a healthy diet had a significantly lower risk of developing T2D, but in individuals who maintained a healthy diet, short sleep duration was still significantly associated with the risk of T2D.
Background and objectives of the study
Numerous studies have demonstrated that short sleep duration adversely affects glucose metabolism, and understanding the interaction between sleep duration, dietary habits, and the risk of developing T2D is critical for public health and diabetes prevention strategies. Therefore, the aim of this study was to explore the association between individual self-reported short sleep duration and maintaining a healthy diet and the incidence of T2D.
Research Methods:
The study was a cohort study that analyzed data from the UK Biobank baseline survey (2006~2010), including a total of 247 867 subjects, with a median follow-up of 12.5 (11.8~13.2) years. According to the length of sleep, the subjects were divided into four groups: normal group (7~8 h/d), mild sleep deprivation group (6 h/d), moderate sleep deprivation group (6 h/d) and extreme sleep deprivation group (3~4 h/d). The primary endpoint was hospital-diagnosed T2D.
Key results
The risk of T2D was significantly increased in the sleepless group (mild, moderate, extreme) compared with the normal sleep group
The median follow-up time was 12.5 (11.8 ~ 13.2) years, and 7905 subjects (3.2%) were diagnosed with T2D. Compared with the normal sleep time group, those who slept for 5 hours per night increased the risk of T2D by 16% and the risk of sleeping for 3~4 hours by 41%.
Figure 1. Length of sleep at baseline and risk of T2D (corrected)
Participants with a high score (4 or 5) had a significantly lower risk of developing T2D than those with the worst healthy eating score (0).
The results showed that participants with a high score (4 or 5) had a significantly lower risk of T2D than those with the worst healthy eating score (0), i.e., a 25% reduction in T2D risk in those with a score of 5 and a 18% reduction in those with a score of 4 (5 points: HR, 0.75 [95% CI, 0.63-0.88], P<0.001;4 points: HR, 0.82 [95% CI, 0.70-0.96], P=0.01; 3 points: HR, 0.89 [95% CI, 0.76-1.04], P=0.13; 2 points: HR, 0.88 [95% CI, 0.76-1.03], P=0.12; 1 point: HR, 0.90 [95% CI, 0.76-1.06], P=0.22) (Figure 2).
Figure 2. Healthy Eating Score and Risk of T2D (Adjusted)
Regardless of whether individuals maintain a healthy diet or not, short sleep duration is still significantly associated with an increased risk of T2D
The results of the study showed that regardless of whether the individual maintained a healthy diet or not, the sleep duration of 5 hours or 3~4 hours was associated with an increased risk of T2D compared to the normal sleep time group. In individuals with a non-healthy diet (0~3 points), the risk of T2D in the 5-hour and 3~4-hour groups increased by 16% and 39%, respectively, compared with the normal sleep group, and in the healthy diet individuals (4~5 points), the risk of T2D in the 5-hour and 3~4-hour sleep groups increased by 17% and 46%, respectively (Fig. 3).
Figure 3. Effect of short baseline sleep duration and dietary status (left: unhealthy diet; right: maintaining a healthy diet) on the risk of developing T2D
Reflection and summary
This cohort study evaluated the relationship between daily sleep duration, eating habits and the risk of T2D in individuals aged 38~71 years, and the results showed that short habitual sleep duration was significantly associated with an increased risk of T2D, and the increased risk was more significant with the further reduction of sleep duration, and this significant association persisted even in subjects who maintained a healthy diet. Previous studies have suggested that sleep deprivation may contribute to the development of T2D through various mechanisms, such as impaired cellular insulin sensitivity, a shift in skeletal muscle energy metabolism to non-glucose oxidation, increased sympathetic nervous system activity, and altered gut microbiota composition.
Most adults have difficulty getting 7~8 hours of sleep per day, and it is important for them to explore alternative strategies to reduce the risk of T2D. Results from a previous clinical trial suggest that engaging in high-intensity exercise may reduce impaired glycemic control after short sleeps [2].
In terms of dietary patterns, considering only the benefits of dietary patterns, we can find that individuals with high healthy eating scores (4 or 5) have a significantly lower risk of developing T2D compared to those with the most unhealthy diets. However, the risk of T2D was significantly increased in both participants who maintained a healthy diet and those who maintained a non-healthy diet as long as the habitual sleep duration was shortened, suggesting that healthy eating habits did not necessarily offset the risk of T2D caused by short habitual sleep duration.
In summary, habitual short sleep duration is significantly associated with an increased risk of T2D. This significant association persisted even in subjects who maintained a healthy diet. To validate these findings, further longitudinal studies, including repeated assessments of sleep (including objective assessments) and eating habits, are needed.
Bibliography:
1.Nôga DA, et al. Habitual Short Sleep Duration, Diet, and Development of Type 2 Diabetes in Adults. JAMA Netw Open. 2024 Mar 4; 7(3):e241147.
2.Saner NJ, et al. Exercise mitigates sleep-loss-induced changes in glucose tolerance, mitochondrial function, sarcoplasmic protein synthesis, and diurnal rhythms. Mol Metab. 2021 Jan;43:101110.