Research indicates that sleep duration and quality are inter-related factors that contribute to obesity, but few studies have focused on sleep chronotype, representing an individual's circadian proclivity, nor assessed these factors in racially diverse middle-aged samples. We examined the associations between chronotype and obesity among black and white men and women participating in the Bogalusa Heart Study (BHS).Body mass index (BMI) and sleep data were available for 1,197 middle-aged men and women (mean age 48.2 ± 5.3 years) who participated in the BHS 2013-2016. Based on the reduced Morningness-Eveningness Questionnaire's cutoff values for chronotypes, we combined 'definitely morning' and 'moderately morning' types into 'morning' type, 'definitely evening' and 'moderately evening' types into 'evening' type and kept those who were "neither" type in a separate group. We used 'morning' type as the referent group. Obesity was defined as a BMI ≥ 30. Multivariable logistic regression models were used to examine associations adjusting for sex, age, education, smoking, alcohol use and drug use, depression, shift work, physical activity and sleep duration.Evening chronotype, reported by 11.1% of participants, was associated with obesity after multi-variable adjustment, including shift work, physical activity and sleep duration (OR 1.67, 95% CI: 1.08-2.56). However, once stratified by race (black/white), this association was found only among white participants (OR = 1.91, 95% CI = 1.12-3.25) after full adjustment.In our biracial, community-based population, evening chronotype was independently associated with obesity, specifically among white participants. Further research is needed to identify behavioral, endocrine, nutritional and genetic pathways which underlie these associations.

中文翻译：

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Bogalusa 心脏研究的黑人和白人参与者的睡眠表型与肥胖之间的关联。

研究表明，睡眠持续时间和质量是导致肥胖的相互关联的因素，但很少有研究关注代表个人昼夜节律倾向的睡眠时间类型，也很少在不同种族的中年样本中评估这些因素。我们研究了参与 Bogalusa 心脏研究 (BHS) 的黑人和白人男性和女性的睡眠类型与肥胖之间的关联。 1,197 名中年男性和女性（平均年龄 48.2 ± 5.3年）谁参加了 BHS 2013-2016。基于减少的晨间-晚间问卷对睡眠类型的截止值，我们将“肯定是早上”和“中等早晨”类型合并为“早上”类型、“肯定晚上”和“中等晚上”类型到“ 晚上”类型并将那些“都不是”类型的人放在一个单独的组中。我们使用“早上”类型作为参考组。肥胖被定义为 BMI ≥ 30。多变量逻辑回归模型用于检查调整性别、年龄、教育、吸烟、饮酒和吸毒、抑郁、轮班工作、身体活动和睡眠时间的关联。 11.1% 的参与者在多变量调整后与肥胖相关，包括轮班工作、身体活动和睡眠时间（OR 1.67，95% CI：1.08-2.56）。然而，一旦按种族（黑人/白人）分层，在完全调整后仅在白人参与者中发现这种关联（OR = 1.91，95% CI = 1.12-3.25）。与肥胖有关，特别是在白人参与者中。需要进一步的研究来确定这些关联背后的行为、内分泌、营养和遗传途径。