Department of Economics, McMaster University, Canada.
Department of Economics, McMaster University, Canada.
Soc Sci Med. 2019 Apr;226:182-189. doi: 10.1016/j.socscimed.2019.02.033. Epub 2019 Mar 1.
Children from low-income families are on average associated with poorer health. Using data on 8, 019 children from who participated in the first five cycles of the Canadian National Longitudinal Survey of Children and Youth (1994/95-2002/03), we find that the gradient of family income on children's health is statistically significant and becomes more pronounced as children age. This conclusion is consistent with some previous studies and the results are more robust in that the Health Utilities Index Mark 3 is used as an alternative measure of children's health, which is conventionally measured using ordinal self-rated health. We also observe that the strong gradient withstands some "third factor" explanations such as parental health and children's health at birth. However, regarding the potential causes of the strong and steepening gradient, contrary to the previous U.S. evidence that attributes part of the gradient to the protective effect of family income on the incidence and severity of children's health problems at birth and chronic conditions (Case et al., 2002), we find no evidence suggesting that children from low-income families suffer more from poor health at birth or recover more slowly from poor health at birth and that higher family income reduces the incidence of chronic conditions or buffers the adverse effects of chronic conditions. The contrast between Canadian and U.S. children may reflect the effects of universal health insurance in Canada. Furthermore, using local unemployment rates to instrument for family income, we find that family income has a statistically significant and economically meaningful causal effect on children's health and that OLS estimates may underestimate the positive impact of family income on children's health. Our findings suggest that universal health insurance may cushion the adverse effects of poor health at birth and chronic conditions but does not eliminate the strong income-related inequality in child health.
来自低收入家庭的儿童平均健康状况较差。利用加拿大儿童纵向研究（1994/95-2002/03 年）的前五个周期中 8019 名儿童的数据，我们发现家庭收入对儿童健康的梯度在统计上是显著的，并且随着儿童年龄的增长而变得更加明显。这一结论与一些先前的研究一致，而且使用健康效用指数标记 3 作为儿童健康的替代衡量标准，而不是通常使用的有序自评健康，结果更加稳健。我们还观察到，即使考虑到一些“第三因素”解释，如父母健康和儿童出生时的健康状况，这种强烈的梯度仍然存在。然而，关于这种强梯度和逐渐加剧的潜在原因，与之前美国的证据不同，美国的证据认为部分梯度归因于家庭收入对儿童出生时健康问题和慢性疾病的发生率和严重程度的保护作用（Case 等人，2002 年），我们没有发现证据表明低收入家庭的儿童在出生时更易患健康问题，或者从出生时的健康不良中恢复得更慢，也没有证据表明较高的家庭收入可以降低慢性疾病的发生率，或者缓冲慢性疾病的不利影响。加拿大和美国儿童之间的差异可能反映了加拿大全民医疗保险的影响。此外，使用当地失业率作为家庭收入的工具变量，我们发现家庭收入对儿童健康具有统计学意义和经济意义上的因果影响，OLS 估计可能低估了家庭收入对儿童健康的积极影响。我们的研究结果表明，全民医疗保险可能缓冲了出生时健康不良和慢性疾病的不利影响，但并没有消除儿童健康方面的强烈收入相关不平等。
