Sleeping less than 6 hours daily may raise type 2 diabetes risk, regardless of healthy eating habits: JAMA

"Individuals getting sleep of less than 6 hours daily had a notably higher risk of T2D development versus those with 7 to 8 hours of sleep," the researchers reported in their study published in JAMA Network Open. 

Despite the association between healthier diets and reduced risk of type 2 diabetes, the increased risk linked with short sleep duration persisted even among adults with healthy eating habits.

Previous studies have revealed substantial evidence of the adverse impact of short sleep duration on glucose metabolism. In contrast, current literature does not provide strong evidence that extended sleep in individuals with normal sleep patterns significantly disrupts glucose regulation. Thus, the association between habitual long sleep duration, often defined as more than 8 or 9 hours per day, and type 2 diabetes may not be causally linked.

Understanding the interplay between dietary habits, sleep duration, and the risk of T2D development is crucial for public health and diabetes prevention strategies. Considering this, Diana Aline Nôga, Department of Pharmaceutical Biosciences, Uppsala University, Sweden, and colleagues aimed to investigate the associations of type of diet and duration of sleep with type 2 diabetes development.

For this purpose, they analyzed data derived from the UK Biobank baseline investigation (2006-2010) between n May 1 and September 30, 2023. During a median follow-up of 12.5 years (end of follow-up, September 30, 2021), the association between sleep duration and healthy dietary patterns with the risk of T2D was investigated.

For the analysis, 247 867 participants were divided into four sleep duration groups: normal (7-8 hours per day), mild short (6 hours per day), moderate short (5 hours per day), and extreme short (3-4 hours per day). Their dietary habits were assessed based on population-specific consumption of processed meat, red meat, vegetables, fruits, and fish, resulting in a healthy diet score ranging from 0 (unhealthiest) to 5 (healthiest). The cohort comprised 247 867 participants with a mean age of 55.9 years; 52.3% were female.

Cox proportional hazards regression analysis was used to calculate hazard ratios (HRs) T2D development across various sleep duration groups and healthy diet scores.

The study led to the following findings:

• During the follow-up, 3.2% of participants were diagnosed with type 2 diabetes based on hospital registry data.
• Cox regression analysis, adjusted for confounding variables, indicated a significant increase in the risk of T2D among participants with 5 hours or less of daily sleep.
• Individuals sleeping 5 hours per day exhibited a 1.16 adjusted HR, and individuals sleeping 3 to 4 hours per day exhibited a 1.41 adjusted HR compared with individuals with normal sleep duration.
• Individuals with the healthiest dietary patterns had a reduced risk of T2D (HR, 0.75).
• The association between short sleep duration and increased risk of T2D persisted even for individuals following a healthy diet, and there was no multiplicative interaction between sleep duration and healthy diet score.

In conclusion, the cohort study involving UK residents found that habitual short sleep duration is associated with an increased risk of developing type 2 diabetes. The association persisted even among those who maintained a healthy diet.

"To validate these findings, there is a need for further longitudinal studies, incorporating repeated measures of sleep (including objective assessments) and dietary habits," the researchers wrote.

Reference:

Nôga DA, Meth EDMES, Pacheco AP, et al. Habitual Short Sleep Duration, Diet, and Development of Type 2 Diabetes in Adults. JAMA Netw Open. 2024;7(3):e241147. doi:10.1001/jamanetworkopen.2024.1147