Scientists from Brigham and Women’s Hospital in Boston, USA, have linked the evening chronotype with an increased risk of type 2 diabetes. According to a study published in the Annals of Internal Medicine, night time activity increases the likelihood of developing this condition by 19 percent compared to “early birds.”
During the study, the researchers analysed data from 63,000 participants (all of whom were women) collected between 2009 and 2017. The participants were categorized into groups based on their chronotype, which was determined during surveys. Other factors taken into account included diet quality, weight, body mass index (BMI), smoking, alcohol consumption, physical activity, hours of sleep per day, and family history.
Approximately 11 percent of the participants reported having an evening chronotype, while 35 percent identified as morning chronotypes. The remaining sample (approximately half) fell into the intermediate category.
The results showed that “night owls” were 72 percent more likely to develop diabetes compared to “early birds.” However, this statistic was observed before adjusting for lifestyle factors. After correction, the increased likelihood of the disease for “night owls” was 19 percent.
Interestingly, among participants leading the healthiest lifestyles, only six percent had an evening chronotype. Among those leading the unhealthiest lifestyles, 25 percent were “night owls.” Furthermore, individuals with an evening chronotype consumed more alcohol in larger quantities, had poorer diets, slept fewer hours per day, and were more likely to smoke. However, “night owls” had normal weight, BMI, and levels of physical activity.