Diabetes risk: Night owls more likely to be diagnosed than early birds

Unhealthy lifestyle behaviours most likely to be adopted by night owls mean they have an increased risk of developing Type 2 diabetes compared to early birds, according to a new study.

Unfortunately for night owls, we might have less control over our sleeping patterns than we might like. The term “night owl” doesn’t just refer to people who choose to stay up late, but instead refers to a person’s circadian preference – a natural body clock that is partly controlled by genetics to stay up late.

This means that night owls are actually wired differently from people who find it easier to wake up early and sleep earlier – also known as early birds. More than 60,000 female nurses who participated in the Nurses’ Health Study II showed that night owls are more likely to consume unhealthy diets, exercise less, have a higher body-mass index, sleep fewer hours and smoke cigarettes than early birds.

The findings are according to a report published in the Annals of Internal Medicine. The study found that night owls were more likely to develop diabetes by 19 per cent compared to early birds. This is largely due to the impact of the unhealthy habits associated with being a night owl.

Tianyi Huang, the study’s senior author and assistant professor of medicine at the Harvard Medical School and an associate epidemiologist at the Brigham and Women’s in Boston, said: “At 19 per cent increased risk, after adjusting for other factors, is a strong risk factor.”

A total of 11 per cent of women in the study reported they were night owls, while 35 per cent said they were early birds. The other half didn’t identify strongly with being either a morning or evening person.

Night owls ‘need to be careful about lifestyle habits’

The new research shows that a so-called evening chronotype – feeling more energetic at night – can lead to bad health consequences. Huang said: “Many night owls go to bed late but have to get up early in the day to work. In our study we found that among people with an evening chronotype who did night shift work there was no association with an increased risk of diabetes.”

Marie-Pierre St-Onge, director of the Center of Excellence for Sleep and Circadian Research at Columbia University Vagelos College of Physicians and Surgeons, said night owls need to be careful about their lifestyle habits if it’s not possible to find jobs that can be done later in the day. “If you are able to eat healthy, sleep well and be physically active, you’re at a lesser risk,” he added.

Can night owls change their sleeping patterns?

While it’s possible for night owls to change their sleeping patterns, St-Onge said: “They tend to revert back. You can’t fight your body.” Huang added: “Some people may have a very strong genetic influence for having an evening chronotype. That is what makes it very hard to alter.”

However, there is a potential evolutionary explanation behind the need for night owls. St-Onge suggests that in the past there was a “need for some people to be vigilant at night, when others could not be. That way, there could be 24-hour coverage in terms of safety”.