China Center for Food Security Studies, Nanjing Agricultural University, 1# Weigang, Xuanwu District, Nanjing, China.
Department of Agricultural Economics and Rural Development, University of Göttingen, Wilhelm-Weber-Str. 2, Goettingen, 37073, Germany.
Econ Hum Biol. 2020 May;37:100847. doi: 10.1016/j.ehb.2020.100847. Epub 2020 Jan 13.
Family planning policy in China has resulted in a large number of one-child families. According to Becker's "quantity-quality trade-off" theory there is an inverse relationship between the number of children in a family, and spending per child. We test whether this has led to significant differences in the height, weight and BMI of only-children compared with children with siblings in China using 4414 observations derived from four recent waves (2004, 2006, 2009, and 2011) of the China Health and Nutrition Survey. We use propensity score matching and instrumental variables to control for the possible endogeneity of the number of siblings. Results show that only-children are significantly heavier (1.88 %-3.86 %), and have higher BMI (2.59 %-3.50 %). Moreover, they are more likely to be obese than children with siblings (2.33 %-3.00 %). Further analysis shows that these differences in health outcomes might be attributable to higher consumption of animal-source food (23.90-27.13 g), a higher frequency of eating western fast food (0.48-0.70 times/3-month) and drinking sweetened soft drinks (0.29-0.36 times/month), a higher share of meals eaten away from home (4.67 %-5.31 %), and more sedentary activity (20.04-34.35 minutes/week) by only children. Our study indicates that the growing share of only children due to China's family planning policies also contributes to the increasing prevalence of overweight and obesity in China. This policy has been eased in recent years, which might slow the increase in the prevalence of overweight and obesity and thus reduce the corresponding health burden for Chinese society as a whole.
中国的计划生育政策导致了大量的独生子女家庭。根据贝克尔的“数量-质量权衡”理论，家庭中孩子的数量与每个孩子的支出成反比。我们利用中国健康与营养调查（China Health and Nutrition Survey）最近四次（2004、2006、2009 和 2011 年）的调查数据，检验了这种情况是否导致了中国独生子女与有兄弟姐妹的儿童在身高、体重和 BMI 方面存在显著差异。我们使用倾向评分匹配和工具变量来控制兄弟姐妹数量的内生性。结果表明，独生子女的体重明显更重（1.88%-3.86%），BMI 更高（2.59%-3.50%）。此外，他们肥胖的可能性也高于有兄弟姐妹的儿童（2.33%-3.00%）。进一步的分析表明，这些健康结果的差异可能归因于他们更高的动物源食品消费（23.90-27.13g）、更高的西式快餐消费频率（0.48-0.70 次/3 个月）、更多的含糖软饮料消费（0.29-0.36 次/月）、更高的外出就餐比例（4.67%-5.31%）以及更少的久坐活动（20.04-34.35 分钟/周）。我们的研究表明，由于中国的计划生育政策，独生子女的比例不断增加，这也导致了中国超重和肥胖的患病率不断上升。近年来，该政策有所放宽，这可能会减缓超重和肥胖患病率的上升速度，从而减轻整个中国社会相应的健康负担。
