Am J Epidemiol. 2021 Apr 6;190(4):630-641. doi: 10.1093/aje/kwaa221.
Union members enjoy better wages and benefits and greater power than nonmembers, which can improve health. However, the longitudinal union-health relationship remains uncertain, partially because of healthy-worker bias, which cannot be addressed without high-quality data and methods that account for exposure-confounder feedback and structural nonpositivity. Applying one such method, the parametric g-formula, to US-based Panel Study of Income Dynamics data, we analyzed the longitudinal relationships between union membership, poor/fair self-rated health (SRH), and moderate mental illness (Kessler 6-item score of ≥5). The SRH analyses included 16,719 respondents followed from 1985-2017, while the mental-illness analyses included 5,813 respondents followed from 2001-2017. Using the parametric g-formula, we contrasted cumulative incidence of the outcomes under 2 scenarios, one in which we set all employed-person-years to union-member employed-person-years (union scenario), and one in which we set no employed-person-years to union-member employed-person-years (nonunion scenario). We also examined whether the contrast varied by sex, sex and race, and sex and education. Overall, the union scenario was not associated with reduced incidence of poor/fair SRH (relative risk = 1.01, 95% confidence interval (CI): 0.95, 1.09; risk difference = 0.01, 95% CI: -0.03, 0.04) or moderate mental illness (relative risk = 1.02, 95% CI: 0.92, 1.12; risk difference = 0.01, 95% CI: -0.04, 0.06) relative to the nonunion scenario. These associations largely did not vary by subgroup.
工会成员享有比非成员更好的工资和福利以及更大的权力，这可以改善健康状况。然而，工会与健康的纵向关系仍然不确定，部分原因是健康工人偏差，这种偏差在没有高质量数据和方法的情况下无法解决，这些数据和方法需要考虑暴露混杂反馈和结构非正定性。我们应用了一种这样的方法，即参数 g 公式，来分析美国收入动态面板研究数据中工会成员身份、较差/一般自我报告健康状况（SRH）和中度精神疾病（Kessler 6 项得分≥5）之间的纵向关系。SRH 分析包括 1985-2017 年期间 16719 名受访者，而精神疾病分析包括 2001-2017 年期间 5813 名受访者。使用参数 g 公式，我们对比了在两种情况下的结果累积发生率，一种情况是我们将所有就业人年设置为工会成员就业人年（工会情景），另一种情况是我们将没有就业人年设置为工会成员就业人年（非工会情景）。我们还检查了这种对比是否因性别、性别和种族以及性别和教育而有所不同。总的来说，工会情景与较差/一般 SRH 的发病率降低无关（相对风险=1.01，95%置信区间（CI）：0.95，1.09；风险差异=0.01，95% CI：-0.03，0.04）或中度精神疾病（相对风险=1.02，95% CI：0.92，1.12；风险差异=0.01，95% CI：-0.04，0.06）与非工会情景相比。这些关联在很大程度上不因亚组而异。
