The Association Between Chronotype and Weight Change Among Medical Students: A Cross-Sectional Study

Area of Science:

• Chronobiology
• Medical Education
• Nutritional Science

Background:

• Chronotype, an individual's natural inclination towards specific sleep-wake times, influences physiological processes.
• Medical students often experience disrupted sleep patterns and lifestyle changes that can affect weight.
• Understanding the relationship between chronotype and weight change is crucial for student well-being.

Purpose of the Study:

• To investigate weight change differences among medical students with varying chronotypes.
• To assess the association between chronotype and weight change, controlling for potential confounders.

Main Methods:

• A cohort of 1300 medical students (excluding freshmen) was surveyed using the Chinese version of the MEQ-5 questionnaire to determine chronotype.
• Weight change was measured as the difference between current weight and admission weight, with weight gain defined as a ≥10% increase.
• Multiple linear and logistic regression models were employed to analyze the data.

Main Results:

• Definite evening-type students exhibited poorer sleep quality, shorter sleep duration, and less frequent breakfast consumption.
• Compared to morning types, evening chronotypes showed a significant increasing trend in weight change (0.88 kg average gain for definite evening types).
• Evening chronotype, combined with dinner after 6 PM, significantly increased the odds of weight gain (OR=2.43).

Conclusions:

• Definite evening chronotype is associated with greater weight increase and a higher likelihood of weight gain in medical students.
• The timing of dinner, especially for evening chronotypes, plays a significant role in weight gain.
• Promoting morning chronotype tendencies and earlier dinner times may be beneficial for weight control in this population.