Night owls are more likely to develop diabetes, warns a new study.
But it’s not just due to an unhealthy lifestyle that people who burn the candle at both ends are more at risk, say scientists.
Researchers found that people who stay up all hours have a higher body mass index (BMI), larger waists, more hidden body fat and are almost 50% more likely to develop type 2 diabetes than those who go to bed earlier.
Study leader Dr. Jeroen van der Velde, of Leiden University Medical Center in Holland, said: “Previous studies have indicated that a late chronotype – preferring to go to bed late and wake up later – is associated with an unhealthy lifestyle.
“Late chronotypes are more likely to smoke or have an unhealthy diet, for example, and it has been suggested this is why they are higher risk of obesity and metabolic disorders including type 2 diabetes.
“However, we believe that lifestyle cannot fully explain the relationship between a late chronotype and metabolic disorders.
“In addition, while it is known that a late chronotype is associated with high BMI, it isn’t clear to what extent chronotype affects body fat distribution.”
Dr. van der Velde and his colleagues analyzed the association between sleep timing, diabetes and body fat distribution in more than 5,000 people as part of the Netherlands Epidemiology of Obesity study, an ongoing research project looking at the influence of body fat on disease.
The participants were an average age of 56 with a mean BMI of 30 kg/m2. Just over half were women,
They filled in a questionnaire regarding their typical bed and waking times and from this a midpoint of sleep (MPS) was calculated.
The participants were then divided into three groups: early, late and intermediate chronotype.
BMI and waist circumference were measured in all the participants while visceral fat and liver fat were measured in 1,526 participants.
The participants were followed up for around six-and-a-half years, during which period 225 were diagnosed with T2D.
The results showed that compared with an intermediate chronotype, participants with a late chronotype had a 46% higher risk of developing type 2 diabetes.
Thar suggests that the increased diabetes risk in late chronotypes can’t be explained by lifestyle alone, according to the research team.
Dr. van der Velde said: “We believe that other mechanisms are also at play.
“A likely explanation is that the circadian rhythm or body clock in late chronotypes is out of sync with the work and social schedules followed by society.
“This can lead to circadian misalignment, which we know can lead to metabolic disturbances and ultimately type 2 diabetes.”
The team also looked at diabetes risk in early chronotypes.
Dr. van der Velde said: “From the literature, we expected early chronotypes to have a similar risk of developing type 2 diabetes as intermediate chronotypes.
“Our results showed a slightly higher risk, but this was not statistically significant.”
The results also showed that late chronotypes had a 0.7 higher BMI, 1.9 cm (0.75 inch) larger waist circumference, more visceral fat and 14% higher liver fat content, compared with those with an intermediate chronotype.
Dr. van der Velde said: “People with a late chronotype appear to be at greater risk of developing type 2 diabetes compared to those with intermediate chronotype, possibly because of higher body fat including more visceral fat and liver fat.
“The next step is to study if those with a late chronotype improve in metabolic health when they make changes in the timing of their lifestyle habits.”
He says one example could be altering the timing of meals.
Dr. van der Velde said: “People with a late chronotype are probably more likely to eat until later in the evening.
“While we did not measure this in our study, there is growing evidence that time-restricted eating, not eating anything after a certain time, such as 6 pm, may lead to metabolic benefits.
“Night owls who are concerned about the increased risk of type 2 diabetes might want to try this or, at least, try to refrain from eating late in the evening.”
He added: “The evidence isn’t there yet but, in time, we aim to provide specific advice regarding the timing of lifestyle behavior.”
The findings are due to be presented at the annual meeting of the European Association for the Study of Diabetes (EASD) in Madrid, Spain.
Produced in association with SWNS Talker
