Study: Night owls likely to develop diabetes

BOSTON: In a recent study conducted by investigators from Brigham and Women’s Hospital, Boston,  it was discovered that individuals with evening “chronotypes” – those who go to bed late and wake up late – are at a 19 per cent higher risk of developing diabetes, even after accounting for lifestyle factors.

The study’s findings, published in the Annals of Internal Medicine, emphasise the significance of considering one’s sleep-wake patterns in relation to health outcomes.

An associate epidemiologist in the Brigham’s Channing Division of Network Medicine and corresponding author of the study Tianyi Huang said: “Chronotype, or circadian preference, refers to a person’s preferred timing of sleep and waking and is partly genetically determined so it may be difficult to change. People who think they are ‘night owls’ may need to pay more attention to their lifestyle because their evening chronotype may add increased risk for type 2 diabetes.”

Meanwhile, previous research had indicated that individuals with irregular sleep schedules faced a higher risk of developing diabetes and cardiovascular disease, with evening chronotypes often displaying irregular sleep patterns.

In this study, researchers delved into the relationship between chronotype and diabetes risk while also examining the role of lifestyle factors.

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The study involved an analysis of data from 63,676 female nurses enrolled in the Nurses’ Health Study II, covering the years 2009 to 2017. It included assessments of self-reported chronotype, diet quality, weight, body mass index (BMI), sleep timing, smoking habits, alcohol consumption, physical activity, and family history of diabetes. Diabetes status was determined through self-reports and medical records.

The findings revealed that individuals with an evening chronotype had a 72 per cent increased risk of diabetes before accounting for lifestyle factors. Even after adjusting for these factors, the risk remained elevated at 19 percent.

Notably, among participants with the healthiest lifestyles, only 6 per cent were evening chronotypes, whereas among those with unhealthy lifestyles, 25 per cent identified as evening chronotypes.

Evening chronotypes were associated with higher alcohol consumption, poorer dietary choices, fewer hours of nightly sleep, current smoking habits, and unhealthy weight, BMI, and physical activity levels.

The study also observed the link between evening chronotype and diabetes risk specifically in nurses who worked day shifts, not in those working overnight shifts.

The study suggests that tailored work scheduling based on chronotype could be beneficial in managing health risks.

It’s important to note that the Nurses’ Health Study primarily involved white female nurses, and further research is needed to determine if these findings apply to broader populations.

Additionally, while the study indicates associations, it does not establish causality, leaving room for the possibility that other factors may contribute to an individual’s chronotype, unhealthy habits, and diabetes risk.

Future investigations will explore genetic determinants of chronotype and its potential association with cardiovascular diseases in more diverse and larger populations, aiming to provide a better understanding of the link between chronotype and various health conditions.