Dataset Information

Nationwide Study of Short-term Exposure to Fine Particulate Matter and Cardiovascular Hospitalizations Among Medicaid Enrollees.

ABSTRACT:

Background

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.

Methods

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).

Results

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.

Conclusion

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.

SUBMITTER: deSouza P

PROVIDER: S-EPMC7896354 | biostudies-literature |

REPOSITORIES: biostudies-literature

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Project description:ImportanceThe association between short-term exposure to air pollution and mortality has been widely documented worldwide; however, few studies have applied causal modeling approaches to account for unmeasured confounders that vary across time and space.ObjectiveTo estimate the association between short-term changes in fine particulate matter (PM2.5) and nitrogen dioxide (NO2) concentrations and changes in daily all-cause mortality rates using a causal modeling approach.Design, setting, and participantsThis cross-sectional study used air pollution and mortality data from Jiangsu, China; California; central-southern Italy; and Germany with interactive fixed-effects models to control for both measured and unmeasured spatiotemporal confounders. A total of 8 963 352 deaths in these 4 regions from January 1, 2015, to December 31, 2019, were included in the study. Data were analyzed from June 1, 2021, to October 30, 2023.ExposureDay-to-day changes in county- or municipality-level mean PM2.5 and NO2 concentrations.Main outcomes and measuresDay-to-day changes in county- or municipality-level all-cause mortality rates.ResultsAmong the 8 963 352 deaths in the 4 study regions, a 10-μg/m3 increase in daily PM2.5 concentration was associated with an increase in daily all-cause deaths per 100 000 people of 0.01 (95% CI, 0.001-0.01) in Jiangsu, 0.03 (95% CI, 0.004-0.05) in California, 0.10 (95% CI, 0.07-0.14) in central-southern Italy, and 0.04 (95% CI, 0.02- 0.05) in Germany. The corresponding increases in mortality rates for a 10-μg/m3 increase in NO2 concentration were 0.04 (95% CI, 0.03-0.05) in Jiangsu, 0.03 (95% CI, 0.01-0.04) in California, 0.10 (95% CI, 0.05-0.15) in central-southern Italy, and 0.05 (95% CI, 0.04-0.06) in Germany. Significant effect modifications by age were observed in all regions, by sex in Germany (eg, 0.05 [95% CI, 0.03-0.06] for females in the single-pollutant model of PM2.5), and by urbanicity in Jiangsu (0.07 [95% CI, 0.04-0.10] for rural counties in the 2-pollutant model of NO2).Conclusions and relevanceThe findings of this cross-sectional study contribute to the growing body of evidence that increases in short-term exposures to PM2.5 and NO2 may be associated with increases in all-cause mortality rates. The interactive fixed-effects model, which controls for unmeasured spatial and temporal confounders, including unmeasured time-varying confounders in different spatial units, can be used to estimate associations between changes in short-term exposure to air pollution and changes in health outcomes.