Background
Circadian misalignment is associated with metabolic syndrome. This study aimed to examine the association between circadian rhythm-disturbing factors and metabolic syndrome.
Methods
We used data from the 7th and 8th Korea National Health and Nutrition Examination Survey conducted between 2016 and 2020, which surveyed 16,253 individuals. Circadian rhythm-disturbing factors were defined as follows: sleep duration outside the reference group (6–8 hours), irregular breakfast, shift work, and physical inactivity. The adjusted odds ratio (aOR) for metabolic syndrome was calculated based on the number of circadian rhythm-disturbing factors present in adults over the age of 19 years.
Results
Among a total of 16,253 participants (mean age 48.2±15 years), metabolic syndrome was found in 5,237 participants (29.3%). The participants were classified into three categories based on the number of circadian rhythm-disturbing factors as follows: 2,627 (15.6%) did not have any factors, 6,406 (38.13%) had one factor, and 7,220 (46.3%) had two or more factors. Participants with a single circadian rhythm-disturbing factor were 21% more likely to have metabolic syndrome (aOR, 1.21; 95% confidence interval [CI], 1.08–1.36), and participants with two or more factors were 27% more likely to have metabolic syndrome (aOR, 1.27; 95% CI, 1.12–1.43).
Conclusion
Circadian rhythm-disturbing factors were significantly associated with the prevalence of metabolic syndrome in Korean adults. This finding has potential clinical implications for maintaining circadian rhythms by avoiding certain factors to prevent metabolic syndrome. Further studies are required to confirm these findings.

Citations

• Cumulative circadian disruption factors and metabolic syndrome
  Jungun Lee
  Korean Journal of Family Medicine.2025; 46(3): 125.     CrossRef

Background
Recently, the prevalence of childhood obesity has increased dramatically, but the cause still remains incompletely understood. The goal of this study was to present a direction for treatment and prevention of childhood obesity on the basis of the data of physical activity energy expenditure, inactive time and dietary habits of Korean children. Methods: A total of 56 children were selected from 8 elementary schools in Seoul and Gwacheon-city. Children's physical activity pattern and dietary habits were obtained by questionnaire. The children wore accelerometer on their wrists from Friday to Tuesday over the whole weekend. Then, we calculated the activity energy expenditure using the activity counts recorded on the accelerometer. Results: Neither the physical activity energy expenditure (kcal/kg) nor the activity pattern showed a significant difference between the normal weight group and the overweight group. The overweight children spent more time watching TV and using the computer. The overweight group did not have breakfast and ate much more and faster in terms of dietary habit. Conclusion: This study suggests that bad habituations in diet and increase of inactivity time can play more important role than physical activity in causing overweight in 7-year-old children. (J Korean Acad Fam Med 2007;28: 195-203)