[The associations between nighttime sleep duration, bedtime and preschool children's obesity].

Objective: To examine the relationship of nighttime sleep duration and bedtime with preschool children's obesity, and to explore possible early life risk factors for childhood obesity. Methods: A total of 14 946 valid children from 16 439 pre-school children aged 3-6 years in 91 kindergartens in Ma'anshan city participated in the study. The body mass index cut-offs for overweight and obesity in Chinese children and adolescents aged 2-18 years was used as the criterion for judging overweight and obesity, and pathological and secondary causes of obesity were excluded. The associations of nighttime sleep duration and bedtime with preschool children's obesity was analyzed by using non-conditional multivariate binary logistic regression model. Results: Among the preschool children, 22.4% (n=3 345) had shorter sleep duration. 9.5% (n=1 415) had bedtimes after 22:00 on weekdays and 21.8% (n=3 260) had bedtimes after 22:00 on weekends. The prevalence of overweight and obesity were 16.5% (n=2 466) and 10.5% (n=1 562), respectively. After the adjustent of age, gender, whether or not only child, residence in the last six months, parents' body mass index parents' educational level, diet preference, outdoor activities, TV viewing duration, sleep duration, bedtime on weekdays and weekends, only the shorter sleep duration (OR=1.25, 95%CI: 1.03-1.51) was still positively associated with the prevalence of obesity in preschool children. Conclusion: Shorter sleep duration was positively associated with the prevalence of obesity among preschool children.目的： 分析夜间睡眠时间和就寝时间与学龄前儿童肥胖的关系，探讨影响学龄前儿童肥胖的生命早期因素。 方法： 2014年4—6月以马鞍山市内登记注册的91所幼儿园16 439名3~6岁学龄前儿童为研究对象，对14 946名有效样本进行研究分析。以"中国2~18岁儿童青少年超重和肥胖筛查体重指数界值点"作为儿童超重和肥胖的判定依据，排除病理性及继发性肥胖者。采用多因素非条件logistic回归模型分析夜间睡眠时间和就寝时间与学龄前儿童肥胖的关系。 结果： 学龄前儿童夜间睡眠时间较少、学习日就寝时间在22:00以后、周末就寝时间在22:00以后者分别占22.4%（3 345名）、9.5%（1 415名）、21.8%（3 260名）。超重、肥胖率分别为16.5%（2 466名）、10.5%（1 562名）。调整年龄、性别、是否独生子、近6个月主要居住地、父母BMI、父母文化程度、饮食偏好、户外运动频率、看电视时间以及睡眠时间、学习日和周末就寝时间之间的相互混杂影响后，睡眠时间较少（OR=1.25，95%CI：1.03~1.51）与学龄前儿童肥胖正向关联。 结论： 睡眠时间较少与学龄前儿童肥胖的发生有关。.