2023/10/25 The Impact of Chronotype on Diabetes Risk: Insights from a Large-Scale Cohort Study

A recent study conducted by researchers from Harvard-affiliated Brigham and Women’s Hospital sheds light on the significance of chronotype in relation to health outcomes, particularly for night owls. Published in the Annals of Internal Medicine, the study unveils compelling findings regarding the link between one's preferred sleep and wake times, lifestyle choices, and the risk of developing Type 2 diabetes.

Chronotype, defined as an individual's circadian preference for sleep and wake timing, was identified as partially genetically determined, making it challenging to modify. The study, led by corresponding author Tianyi Huang, an assistant professor of medicine at Harvard Medical School, examined how evening chronotypes were associated with an increased susceptibility to Type 2 diabetes.

Drawing upon data from 63,676 female participants in the Nurses’ Health Study II, spanning the years 2009 to 2017, the researchers analyzed self-reported chronotype, dietary habits, body weight, sleep patterns, smoking habits, alcohol consumption, physical activity, and family history of diabetes. They verified diabetes status through self-reports and medical records.

Notably, the study revealed that individuals with an evening chronotype faced a 72 percent higher risk of diabetes, a risk that only diminished to 19 percent after accounting for lifestyle factors. Among participants with healthier lifestyles, a mere 6 percent exhibited evening chronotypes, in stark contrast to 25 percent among those with less healthy lifestyles. Evening chronotype individuals were also more likely to engage in high alcohol consumption, maintain a low-quality diet, experience shorter nightly sleep durations, smoke, and have unhealthy weight, BMI, and physical activity levels.

While the study primarily focused on white female nurses, future investigations will explore whether these patterns hold true across diverse populations. Although causality remains unconfirmed, these findings underscore the need for personalized prevention strategies, with future research examining genetic determinants of chronotype and its relationship with cardiovascular diseases in larger, more diverse cohorts. Establishing causal links could empower physicians to tailor prevention approaches for their patients effectively.