Department of Medical Ethics and Health Policy, Perelman School of Medicine, University of Pennsylvania, Philadelphia.
Leonard Davis Institute of Health Economics, University of Pennsylvania, Philadelphia.
JAMA Intern Med. 2020 Mar 1;180(3):429-436. doi: 10.1001/jamainternmed.2019.6532.
Despite substantial research, the drivers of the widening gap in life expectancy between rich and poor individuals in the United States-known as the longevity gap-remain unknown. The hypothesis of this study is that social mobility may play an important role in explaining the longevity gap.
To assess whether social mobility is associated with income-related differences in life expectancy in the United States.
DESIGN, SETTING, AND PARTICIPANTS: This cross-sectional, ecological study used data from 1559 counties in the United States to assess the association of social mobility with average life expectancy at age 40 years by sex and income quartile among adult men and women over the period of January 2000 through December 2014. Bayesian generalized linear multilevel regression models were used to estimate the association, with adjustment for a range of socioeconomic, demographic, and health care system characteristics.
County-level social mobility, here operationalized as the association of the income rank of individuals born during the period of January 1980 through December 1982 (based on tax record data, averaged over the period January 2010 through December 2012) with the income ranks of their parents (averaged over the period January 1996 through December 2000) using the location where the parent first claimed the child as a dependent at age 15 years to identify counties.
The main outcome was life expectancy at age 40 years by sex and income quartile.
The sample consisted of 1559 counties, which represented 93% of the US population in 2000. Each 1-SD increase in social mobility-equivalent to the difference between a low-mobility state, such as Alabama (ranked 49th on this measure), and a higher-mobility state, such as Massachusetts (ranked 23rd on this measure)-was associated with a 0.38-year (95% credible interval [CrI], 0.29-0.47) and a 0.29-year (95% CrI, 0.21-0.38) increase in county-level life expectancy among men and women, respectively, in the lowest income quartile. Estimates for life expectancies among county residents in the highest income quartile were smaller in magnitude and not robust to covariate adjustment (men: 0.10-year [95% CrI, -0.02 to 0.22] increase; women: 0.08-year [95% CrI, -0.05 to 0.20] increase). Increasing social mobility in all counties to the value of the highest social mobility county was associated with decreases in the life expectancy gap between the highest and lowest income quartiles by 1.4 (95% CrI, 0.7-2.1) years for men and 1.1 (95% CrI, 0.5-1.6) years for women nationally, representing a 20% decrease.
In this cross-sectional study, higher county-level social mobility was associated with smaller county-level gaps in life expectancy by income. These findings motivate further investigation of causal relationships between policies that shift social mobility and health outcomes.
尽管进行了大量研究，但美国贫富个体之间预期寿命差距（即长寿差距）不断扩大的原因仍不得而知。本研究的假设是，社会流动性可能在解释长寿差距方面发挥重要作用。
评估社会流动性是否与美国与收入相关的预期寿命差异相关。
设计、地点和参与者：本横断面、生态学研究使用了美国 1559 个县的数据，评估了社会流动性与 2000 年 1 月至 2014 年 12 月期间成年男性和女性中按性别和收入四分位数划分的 40 岁时平均预期寿命之间的关联，其中包括社会流动性与收入排名之间的关联。在此操作中，个体在 1980 年 1 月至 1982 年 12 月期间出生（基于纳税记录数据，2010 年 1 月至 2012 年 12 月期间平均）与父母的收入排名（1996 年 1 月至 2000 年 12 月期间平均），使用父母首次在 15 岁时将孩子作为受抚养人申报的地点来确定县。
主要结果是按性别和收入四分位数划分的 40 岁时的预期寿命。
样本包括 1559 个县，占 2000 年美国人口的 93%。社会流动性每增加 1 个标准差（相当于从低流动性州，如阿拉巴马州（该州在这项衡量标准中排名第 49 位）到更高流动性州，如马萨诸塞州（该州在这项衡量标准中排名第 23 位）之间的差异）与男性和女性的县一级预期寿命分别增加 0.38 岁（95%可信区间[CrI]，0.29-0.47）和 0.29 岁（95% CrI，0.21-0.38），分别在收入最低的四分位数中。在收入最高的四分位数中，县居民预期寿命的估计值幅度较小，且不受协变量调整的影响（男性：0.10 岁[95% CrI，-0.02 至 0.22]增加；女性：0.08 岁[95% CrI，-0.05 至 0.20]增加）。所有县的社会流动性增加到最高社会流动性县的水平，与最高和最低收入四分位数之间的预期寿命差距减少了 1.4 岁（95% CrI，0.7-2.1），男性为 1.1 岁（95% CrI，0.5-1.6），女性为 1.1 岁。全国范围内减少了 1.1 岁（95% CrI，0.5-1.6），全国范围内减少了 1.1 岁（95% CrI，0.5-1.6），这代表了 20%的降幅。
在这项横断面研究中，较高的县一级社会流动性与按收入划分的县一级预期寿命差距较小相关。这些发现促使进一步调查改变社会流动性和健康结果的政策之间的因果关系。
