Background: The disruption of circadian rhythm has been found to associate with obesity in vivo and in vitro. Sleep duration, eating habits, total feeding time, and nightshift work can also affect circadian rhythms. This study investigated the association between misalignment of circadian rhythm and obesity in Korean men, using a cross-sectional database.Methods: This study used data from the Korean National Health and Nutrition Examination Survey (KNHANES), whose study population was 3,658 men aged 18 to 60 years. General and abdominal obesity was defined as a body mass index (BMI) ≥ 25 kg/m2 and waist circumference ≥ 90 cm, respectively. Circadian rhythm factors were determined with a self-report questionnaire and included breakfast frequency, sleep duration, and work time. Frequency of breakfast was divided into regular breakfast (five to seven times a week) and irregular breakfast (less than five times a week). Sleep duration was divided into less than 7 hours, 7-9 hours, and over 9 hours. Working time was defined as day/evening, night shift, and other type. The adjusted odds ratios (aORs) and 95% confidence intervals (CIs) for general and abdominal obesity were calculated using multivariable logistic regression according to the number of factors that disturb the circadian rhythm.Results: Participants with 1 (aOR 1.34, 95% Cl 1.10-1.61) and ≥2 (aOR 1.62, 95% Cl 1.29-2.05) factors disturbing circadian rhythms were associated with elevated risk for general obesity. Similarly, those with 1 (aOR 1.33, 95% Cl 1.09-1.63) and ≥2 (aOR 1.70, 95% Cl 1.32-2.20) factors had elevated risk for abdominal obesity.Conclusions: Factors disturbing the circadian rhythm were associated with general and abdominal obesity. Additional studies are needed, and associations with metabolic diseases should be investigated.

中文翻译：

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昼夜节律失调与韩国男性肥胖之间的关联：第六次韩国国家健康与营养调查。

背景：在体内和体外发现昼夜节律紊乱与肥胖有关。睡眠时间，饮食习惯，总进食时间和夜班工作也会影响昼夜节律。本研究使用横断面数据库调查了韩国男性的昼夜节律失调与肥胖之间的关系。方法：本研究使用了韩国国家健康与营养检查调查（KNHANES）的数据，该研究人群为3,658岁的18岁男性。到60年 全身肥胖和腹部肥胖分别定义为体重指数（BMI）≥25 kg / m2和腰围≥90 cm。通过自我报告调查表确定昼夜节律因素，包括早餐频率，睡眠时间和工作时间。早餐的频率分为常规早餐（每周五次至七次）和不规则早餐（每周少于五次）。睡眠时间分为少于7小时，7-9小时和超过9小时。工作时间被定义为白天/晚上，夜班和其他类型。根据影响昼夜节律的因素数量，使用多变量logistic回归计算经校正的比值比（aOR）和95％置信区间（CIs）。结果：参与者的1（aOR 1.34，95％Cl 1.10-1.61）和≥2（aOR 1.62，95％Cl 1.29-2.05）干扰昼夜节律的因素与一般肥胖的风险增加有关。同样，具有1（aOR 1.33，95％Cl 1.09-1.63）和≥2（aOR 1.70，95％Cl 1.32-2.20）因子的人发生腹部肥胖的风险升高。干扰昼夜节律的因素与普通和腹部肥胖有关。需要进行进一步的研究，并应调查与代谢疾病的关系。