Night Owls at Higher Risk for Metabolic Disorders

People who habitually stay up late are more likely to develop diabetes, metabolic syndrome and sarcopenia than early risers.

People who habitually stay up late may have an increased risk for developing diabetes, metabolic syndrome and sarcopenia than those who wake up early, even after receiving the same amount of sleep, new data published in the Journal of Clinical Endocrinology & Metabolism indicate.

In the study, 1,620 participants aged 47 to 59 years from the Korean Genome and Epidemiology Study were classified according to chronotype, or their individual circadian preference in behavioral and biological rhythm relative to external light-dark cycle, using the Morningness-Eveningness Questionnaire. Participants also underwent an oral glucose tolerance test and DEXA for body composition assessment.

Of all participants, 29.6% were morning chronotypes, 5.9% were evening chronotypes and 64.5% were neither.

After adjustment for potential confounders, results demonstrated a significant association between evening chronotype and diabetes (OR=1.73; 95% CI, 1.01-2.95), metabolic syndrome (OR=1.74; 95% CI, 1.05-2.87) and sarcopenia (OR=3.16; 95% CI, 1.36-7.33), as compared with morning chronotype.

The researchers also noted differences according to gender. In men, for instance, evening chronotype was linked with both diabetes (OR=2.98; 95% CI, 1.39-6.39) and sarcopenia (OR=3.89; 95% CI, 1.33-11.33), whereas evening chronotype was only associated with metabolic syndrome in women (OR=2.22; 95% CI, 1.11-4.43).

“Regardless of lifestyle, people who stayed up late faced a higher risk of developing health problems like diabetes or reduced muscle mass than those who were early risers,” study author Nan Hee Kim, MD, PhD, of Korea University College of Medicine in Ansan, Korea, said in a press release. “This could be caused by night owls’ tendency to have poorer sleep quality and to engage in unhealthy behaviors like smoking, late-night eating and a sedentary lifestyle.”

Although evening chronotypes were generally younger, they had higher levels of body fat and triglycerides than morning chronotypes. Women who were evening chronotypes also tended to have more belly fat.

“Considering many younger people are evening chronotypes, the metabolic risk associated with their circadian preference is an important health issue that needs to be addressed,” Kim said.


  1. Yu JH et al. J Clin Endocrinol Metab. 2015;doi:10.1210/jc.2014-3754.