Hosseini Sayed Mohsen, Latifi Shakiba, Kelishadi Roya
Department of Biostatistics and Epidemiology, School of Public Health, Isfahan University of Medical Sciences, Isfahan, Iran.
Department of Pediatrics, Child Growth and Development Research Center, Isfahan University of Medical Sciences, Isfahan, Iran.
Adv Biomed Res. 2017 Nov 30;6:152. doi: 10.4103/2277-9175.219417. eCollection 2017.
This study aims to evaluate the effect of some factors, including birth weight, sex, age, waist circumference, family history of obesity, as well as some lifestyle factors as frequency of breakfast days and physical activity, on the body mass index among a nationally representative sample of Iranian children and adolescents by using bootstrapping regression.
This study was conducted as the third survey of a school-based surveillance system (CASPIAN-III study). Total participants were 5570 school students, aged 10-18 years, selected by multistage random cluster sampling from urban and rural areas of 27 provinces of Iran. Multiple linear regressions was used to evaluate the effect of various factors on obesity, but in our data the assumptions of this model violated, and possible solutions were not appropriate, therefore the bootstrapping regression based on the observations and errors resampling approaches was used as an alternative.
The tests of significance showed that the effects of sex, age, waist circumference, family history obesity and frequency of breakfast days were clearly significant ( < 0.001). The effect of vigorous level of physical activity was significant in comparison to mild physical activity ( = 0.01). In comparison to low birth weight, medium and high birth weight had significant effect on obesity.
Bootstrap method is preferable in linear regression because of some theoretical properties like having any distributional assumptions on the residuals and hence allows for inference even if the errors do not follow normal distribution or constant error variance.
本研究旨在通过自抽样回归，评估包括出生体重、性别、年龄、腰围、肥胖家族史以及一些生活方式因素（如早餐天数频率和体育活动）等因素对伊朗儿童和青少年全国代表性样本体重指数的影响。
本研究作为基于学校的监测系统的第三次调查（CASPIAN - III研究）进行。总共有5570名10 - 18岁的在校学生参与，通过多阶段随机整群抽样从伊朗27个省的城乡地区选取。使用多元线性回归评估各种因素对肥胖的影响，但在我们的数据中该模型的假设被违反，且可能的解决方案不合适，因此采用基于观测值和误差重抽样方法的自抽样回归作为替代方法。
显著性检验表明，性别、年龄、腰围、肥胖家族史和早餐天数频率的影响具有明显显著性（<0.001）。与轻度体育活动相比，剧烈体育活动水平的影响具有显著性（=0.01）。与低出生体重相比，中等和高出生体重对肥胖有显著影响。
由于自抽样方法具有一些理论特性，如对残差没有任何分布假设，因此即使误差不服从正态分布或恒定误差方差也允许进行推断，所以在线性回归中自抽样方法更可取。
