Department of Public Health, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, Japan.
J Public Health (Oxf). 2019 Jun 1;41(2):362-370. doi: 10.1093/pubmed/fdy095.
Japan has experienced a low prevalence of childhood obesity. The Japanese nationwide school lunch program is suggested to have helped this phenomenon, but it has not been proven.
From official statistics, we combined annual data for 2006-15 about the prefecture-level school lunch coverage rate for public junior high school students and the prefecture-level nutritional indicators calculated by randomly selected age-sex groups of 13-15-year olds: the percentage of overweight, obese or underweight children, who are 20% heavier, 30% heavier or 20% lighter than the standard weight by sex, age and height; and mean body weight (kg) or height (cm). We estimated the impact of the school lunch coverage rate on the nutritional indicators in subsequent years, adjusting for the lagged dependent variable and dummies for prefecture, age and year.
A 10 percentage point increase in the prefecture-level school lunch coverage rate significantly decreased the percentage of overweight (0.37%, 95% CI: 0.18-0.56) and obesity (0.23%, 0.10-0.37) in subsequent years among boys, but not among girls. No significant effect on the percentage of underweight or mean body weight/height was observed for either sex.
Appropriate nutritional intake through school lunch may be effective to reduce childhood obesity.
日本儿童肥胖的患病率较低。日本全国范围的学校午餐计划被认为对此现象起到了一定作用，但尚未得到证实。
我们结合了 2006 年至 2015 年关于公立初中学生的州级学校午餐覆盖率的年度数据，以及通过随机选择的 13-15 岁年龄性别组计算出的州级营养指标：超重、肥胖或体重不足儿童的百分比，他们的体重比标准体重重 20%、30%或轻 20%，按性别、年龄和身高计算；以及平均体重（kg）或身高（cm）。我们通过滞后因变量和州、年龄和年份的哑变量来调整，估计学校午餐覆盖率对后续年份营养指标的影响。
州级学校午餐覆盖率每增加 10 个百分点，男孩在随后的年份中超重（0.37%，95%CI：0.18-0.56）和肥胖（0.23%，0.10-0.37）的比例显著降低，但对女孩没有显著影响。对任何性别而言，体重不足或平均体重/身高都没有明显影响。
通过学校午餐进行适当的营养摄入可能对减少儿童肥胖有效。
