Department of Epidemiology, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Okayama, Japan.
JAMA Pediatr. 2013 Oct;167(10):919-25. doi: 10.1001/jamapediatrics.2013.2230.
Although it is suggested that breastfeeding is protective against obesity in children, the evidence remains inconclusive because of possible residual confounding by socioeconomic status or children's lifestyle factors. Most of the participants in the previous studies were children in Western developed countries, so studies in a different context are awaited.
To examine the associations of breastfeeding with overweight and obesity among schoolchildren in Japan, with adjustment for the potential confounders.
Secondary data analyses of a nationwide longitudinal survey ongoing since 2001, with results collected from 2001 to 2009.
All over Japan.
A total of 43,367 singleton children who were born after 37 gestational weeks and had information on their feeding during infancy.
Five mutually exclusive infant feeding practice categories.
Underweight, normal weight (referent group), overweight, and obesity at 7 and 8 years of age defined by using international cutoff points of body mass index by sex and age.
In multinomial logistic regression models with adjustment for children's factors (sex, television viewing time, and computer game playing time) and maternal factors (educational attainment, smoking status, and working status), exclusive breastfeeding at 6 to 7 months of age was associated with decreased risk of overweight and obesity compared with formula feeding. The adjusted odds ratios were 0.85 (95% CI, 0.69-1.05) and 0.55 (95% CI, 0.39-0.78) for overweight and obesity, respectively, at 7 years of age. Similar results were observed at 8 years of age.
Breastfeeding is associated with decreased risk of overweight and obesity among schoolchildren in Japan. Therefore, it would be better to encourage breastfeeding even in developed countries.
尽管有研究表明母乳喂养可预防儿童肥胖，但由于社会经济地位或儿童生活方式因素等潜在混杂因素，证据仍不明确。之前的研究大多以西方发达国家的儿童为研究对象，因此期待在不同背景下开展相关研究。
在调整潜在混杂因素后，检验日本学童中母乳喂养与超重和肥胖的相关性。
对一项始于 2001 年的全国性纵向研究进行二次数据分析，研究结果收集于 2001 年至 2009 年。
日本各地。
共纳入 43367 名胎龄 37 周以上、具有婴儿期喂养信息的单胎儿童。
5 种互斥的婴儿喂养方式。
7 岁和 8 岁时，根据国际按性别和年龄划分的 BMI 切点，采用体重指数将儿童分为消瘦、正常体重（参照组）、超重和肥胖。
在调整了儿童因素（性别、看电视时间和玩电脑游戏时间）和母亲因素（受教育程度、吸烟状况和工作状况）的多项二项逻辑回归模型中，6 至 7 月龄时纯母乳喂养与配方奶喂养相比，超重和肥胖的风险降低。7 岁时，调整后的优势比分别为 0.85（95%CI，0.69-1.05）和 0.55（95%CI，0.39-0.78）；8 岁时也观察到类似结果。
在日本学童中，母乳喂养与超重和肥胖风险降低有关。因此，即使在发达国家，鼓励母乳喂养也很有必要。
