From the Department of Urban Studies and Planning, Massachusetts Institute of Technology, Cambridge, MA.
Department of Biostatistics, Harvard T.H. Chan School of Public Health, Boston, MA.
Epidemiology. 2021 Jan;32(1):6-13. doi: 10.1097/EDE.0000000000001265.
Fine particulate matter (PM2.5) has been consistently linked to cardiovascular disease (CVD). Although studies have reported modification by income, to our knowledge, no study to date has examined this relationship among adults in Medicaid, which provides health coverage to low-income and/or disabled Americans.
We estimated the association between short-term PM2.5 exposure (average of PM2.5 on the day of hospitalization and the preceding day) and CVD admissions rates among adult Medicaid enrollees in the continental United States (2000-2012) using a time-stratified case-crossover design. We repeated this analysis at PM2.5 concentrations below the World Health Organization daily guideline of 25 μg/m. We compared the PM2.5-CVD association in the Medicaid ≥65 years old versus non-Medicaid-eligible Medicare enrollees (≥65 years old).
Using information on 3,666,657 CVD hospitalizations among Medicaid adults, we observed a 0.9% (95% CI = 0.6%, 1.1%) increase in CVD admission rates per 10 μg/m PM2.5 increase. The association was stronger at low PM2.5 levels (1.3%; 95% CI = 0.9%, 1.6%). Among Medicaid enrollees ≥65 years old, the association was 0.9% (95% CI = 0.6%, 1.3%) vs. 0.8% (95% CI = 0.6%, 0.9%) among non-Medicaid-eligible Medicare enrollees ≥65 years old.
We found robust evidence of an association between short-term PM2.5 and CVD hospitalizations among the vulnerable subpopulation of adult Medicaid enrollees. Importantly, this association persisted even at PM2.5 levels below the current national standards.
细颗粒物（PM2.5）与心血管疾病（CVD）一直存在关联。尽管已有研究报告称收入可以对此产生影响，但截至目前，还没有研究在为美国低收入和/或残疾人群提供医疗保险的 Medicaid 成年参保者中检验这种关联。
我们采用时间分层病例交叉设计，估计了短期 PM2.5 暴露（住院当天和前一天的 PM2.5 平均值）与美国大陆 Medicaid 成年参保者 CVD 入院率之间的关联（2000-2012 年）。我们在世界卫生组织每日 25μg/m 的 PM2.5 指导值以下的浓度下重复了这一分析。我们比较了 Medicaid ≥65 岁人群与非 Medicaid 合格的 Medicare 参保者（≥65 岁）中 PM2.5 与 CVD 的关联。
使用 Medicaid 成年人群中 3666657 例 CVD 住院数据，我们发现每增加 10μg/m 的 PM2.5，CVD 入院率增加 0.9%（95%CI=0.6%，1.1%）。在较低的 PM2.5 水平下，这种关联更强（1.3%；95%CI=0.9%，1.6%）。在 Medicaid 参保者中，≥65 岁人群的关联为 0.9%（95%CI=0.6%，1.3%），而非 Medicaid 合格的 Medicare 参保者中，≥65 岁人群的关联为 0.8%（95%CI=0.6%，0.9%）。
我们发现，在脆弱的 Medicaid 成年参保者亚人群中，短期 PM2.5 与 CVD 住院之间存在强有力的关联证据。重要的是，即使在低于当前国家标准的 PM2.5 水平下，这种关联仍然存在。
