Night Owls May Face Higher Diabetes Risk

What Did the Research Discover?

This study explored the relationship between chronotype (morning vs. evening preference) and the risk of developing type 2 diabetes in middle-aged nurses. The findings suggest that nurses with an evening chronotype—those who naturally stay up late and wake up later—are more likely to have unhealthy lifestyle habits and a higher risk of diabetes than those with a morning chronotype.

Over an eight-year follow-up period, researchers tracked 63,676 nurses aged 45 to 62 years who had no prior history of diabetes, cardiovascular disease, or cancer. Participants reported their chronotype using a validated questionnaire, and their lifestyle behaviors were assessed, including diet quality, physical activity, smoking, alcohol intake, body mass index (BMI), and sleep duration. New cases of diabetes were self-reported and confirmed through additional questionnaires.

The study found that individuals with a definite evening chronotype were 54% more likely to have an unhealthy lifestyle than those with a definite morning chronotype. During the study period, 1,925 new cases of type 2 diabetes were recorded.

When comparing diabetes risk among different chronotypes, nurses with an intermediate chronotype had a 21% higher risk, while those with a definite evening chronotype had a 72% higher risk compared to morning chronotypes. Even after adjusting for BMI, physical activity, and diet, the risk of diabetes in evening chronotypes remained 31% higher. When all lifestyle and sociodemographic factors were considered, the risk was reduced but still statistically significant, suggesting that chronotype itself may contribute to diabetes risk beyond lifestyle choices.

How Can I Apply This Information?

For individuals, particularly those who identify as evening chronotypes, these findings highlight the importance of maintaining healthy lifestyle habits to counteract increased diabetes risk. Evening chronotypes may need to be especially mindful of improving diet quality, engaging in regular physical activity, maintaining a healthy weight, and getting adequate sleep. Since evening types often struggle with early schedules, finding ways to adapt healthier behaviors to fit their natural rhythms—such as exercising later in the day—may help mitigate their risk.

For healthcare providers, this study underscores the need to consider chronotype when advising patients on diabetes prevention. Since evening chronotypes are more likely to have unhealthy habits, tailored recommendations that align with their natural sleep-wake cycle may be more effective. Providers can also emphasize the risks associated with shift work, which is more common among evening chronotypes and linked to metabolic disorders.

For employers and policymakers, particularly in healthcare and shift-based industries, these findings suggest a need for workplace policies that support metabolic health. Offering flexible work schedules, providing healthier food options, and encouraging wellness programs can help individuals at higher risk maintain better lifestyle habits.

While lifestyle factors remain the primary drivers of diabetes risk, this study indicates that chronotype itself may be an independent risk factor. Evening types may need to take extra precautions to manage their health, and healthcare systems may need to adopt more personalized approaches to diabetes prevention and lifestyle interventions.

Source:

Kianersi S, Liu Y, Guasch-Ferré M, Redline S, Schernhammer E, Sun Q, Huang T. Chronotype, unhealthy lifestyle, and diabetes risk in middle-aged US women: a prospective cohort study. Annals of internal medicine. 2023 Oct;176(10):1330-9. https://www.acpjournals.org/doi/abs/10.7326/M23-0728