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Cited by 703Air Quality and Health ImpactsIndoor Air Quality and Microbial ExposureEnvironmental Justice and Health Disparities

Association of short-term exposure to air pollution with mortality in older adults

Open access
Di, Qian, Dai, Lingzhen, Wang, Yun, Zanobetti, Antonella, Choirat, Christine, Schwartz, Joel D., Dominici, Francesca·2017·JAMA
DOI 10.1001/jama.2017.17923PMC PMC5783186
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Abstract

Importance: The US Environmental Protection Agency is required to reexamine its National Ambient Air Quality Standards (NAAQS) every 5 years, but evidence of mortality risk is lacking at air pollution levels below the current daily NAAQS in unmonitored areas and for sensitive subgroups. Objective: To estimate the association between short-term exposures to ambient fine particulate matter (PM2.5) and ozone, and at levels below the current daily NAAQS, and mortality in the continental United States. Design, Setting, and Participants: Case-crossover design and conditional logistic regression to estimate the association between short-term exposures to PM2.5 and ozone (mean of daily exposure on the same day of death and 1 day prior) and mortality in 2-pollutant models. The study included the entire Medicare population from January 1, 2000, to December 31, 2012, residing in 39 182 zip codes. Exposures: Daily PM2.5 and ozone levels in a 1-km × 1-km grid were estimated using published and validated air pollution prediction models based on land use, chemical transport modeling, and satellite remote sensing data. From these gridded exposures, daily exposures were calculated for every zip code in the United States. Warm-season ozone was defined as ozone levels for the months April to September of each year. Main Outcomes and Measures: All-cause mortality in the entire Medicare population from 2000 to 2012. Results: During the study period, there were 22 433 862 million case days and 76 143 209 control days. Of all case and control days, 93.6% had PM2.5 levels below 25 μg/m3, during which 95.2% of deaths occurred (21 353 817 of 22 433 862), and 91.1% of days had ozone levels below 60 parts per billion, during which 93.4% of deaths occurred (20 955 387 of 22 433 862). The baseline daily mortality rates were 137.33 and 129.44 (per 1 million persons at risk per day) for the entire year and for the warm season, respectively. Each short-term increase of 10 μg/m3 in PM2.5 (adjusted by ozone) and 10 parts per billion (10-9) in warm-season ozone (adjusted by PM2.5) were statistically significantly associated with a relative increase of 1.05% (95% CI, 0.95%-1.15%) and 0.51% (95% CI, 0.41%-0.61%) in daily mortality rate, respectively. Absolute risk differences in daily mortality rate were 1.42 (95% CI, 1.29-1.56) and 0.66 (95% CI, 0.53-0.78) per 1 million persons at risk per day. There was no evidence of a threshold in the exposure-response relationship. Conclusions and Relevance: In the US Medicare population from 2000 to 2012, short-term exposures to PM2.5 and warm-season ozone were significantly associated with increased risk of mortality. This risk occurred at levels below current national air quality standards, suggesting that these standards may need to be reevaluated.

AI snapshot

Written from the paper’s full text.

TL;DR

In a case-crossover analysis of the entire US Medicare population from 2000–2012, short-term PM2.5 and warm-season ozone exposures were significantly associated with increased all-cause mortality, including at concentrations below current daily NAAQS. The authors conclude that current air quality standards may need reevaluation.

Key findings

  • Among 22,433,862 case days and 76,143,209 control days across 39,182 zip codes, each 10 μg/m3 increase in lag 01-day PM2.5 (adjusted for ozone) was associated with a 1.05% (95% CI: 0.95%, 1.15%) increase in daily mortality rate; ARD was 1.42 (95% CI: 1.29, 1.56) per 1 million persons at risk per day.
  • Each 10 ppb increase in warm-season ozone (adjusted for PM2.5) was associated with a 0.51% (95% CI: 0.41%, 0.61%) increase in daily mortality rate; ARD was 0.66 (95% CI: 0.53, 0.78) per 1 million persons at risk per day.
  • Associations remained significant below current daily standards: for PM2.5 <25 μg/m3, RR was 1.61% (95% CI: 1.48%, 1.74%) and ARD 2.17 (95% CI: 2.00, 2.34); for ozone <60 ppb, RR was 0.58% (95% CI: 0.46%, 0.70%) and ARD 0.74 (95% CI: 0.59, 0.90).
  • Higher PM2.5-associated mortality was observed in Medicaid-eligible individuals, those above 70 years, and females; exposure-response curves were almost linear with no evidence of a threshold.

Methods

  • Case-crossover design with conditional logistic regression, comparing each person’s date of death (case day) with matched control days on the same day of week, in the same month, and before/after the case day.
  • Included all Medicare deaths in the continental US from January 1, 2000 to December 31, 2012, residing in 39,182 zip codes; exposures were daily PM2.5 and ozone estimated on a 1 km × 1 km grid using validated prediction models.
  • Two-pollutant models estimated PM2.5 (adjusted for ozone) and warm-season ozone (adjusted for PM2.5) associations using lag 01-day exposure, with natural splines for air and dew point temperature; subgroup and low-exposure analyses were also conducted.

Limitations

  • Stated: the case-crossover design cannot estimate mortality risk from long-term exposure; exposure was assigned by residential zip code rather than exact home address or place of death, likely causing measurement error; the Medicare population is primarily older than 65, limiting generalizability to younger populations; Medicare files lack cause-specific mortality; and the most recent data were nearly 5 years old at publication.
  • Evident from the text: this is an observational study, so the reported associations should not be interpreted as proving causality.

Model-written summary. Check it against the paper before relying on it.

Integrity signals

Registry

Crossref · 10.1001/jama.2017.17923

Cites

42 of 42 references verified0 citation errors · 0 not checkable

Statistics

Nothing to recompute.

Claims the paper makes

0 of 31 cited sources checked · 0 supported · 0 flagged

  • Findingown data

    The absolute risk difference for ozone below 60 ppb was 0.74 per 1 million persons at risk per day (95% CI 0.59 to 0.90).

    “These associations remained significant when examining days below 25 μg/m3 for PM2.5 and below 60 ppb for ozone, with larger effect size estimates for both PM2.5 and ozone (RR: 1.61% [95% CI: 1.48%, 1.74%] and 0.58% [95% CI: 0.46%, 0.70%]; ARD: 2.17 [95% CI: 2.00, 2.34] and 0.74 [95% CI: 0.59, 0.90] per 1M per day)”
    Quote in the paperNot a substantial claim
  • Findingown data

    PM2.5 was associated with a higher mortality rate in females (RR 1.20%, 95% CI 1.07% to 1.33%; ARD 1.56, 95% CI 1.39 to 1.72 per 1M per day; interaction p=0.019).

    “and females (RR: 1.20% [95% CI: 1.07%, 1.33%]; ARD: 1.56 [95% CI: 1.39, 1.72] per 1M per day, interaction: p=0.019)”
    Quote in the paperNot a substantial claim
  • Findingown data

    The absolute risk difference for PM2.5 was 1.42 per 1 million persons at risk per day (95% CI 1.29 to 1.56).

    “Absolute risk differences in daily mortality rate were 1.42 (95% CI: 1.29, 1.56) and 0.66 (95% CI: 0.53, 0.78) per 1 million persons at risk per day.”
    Quote in the paperNot a substantial claim
  • Findingown data

    When restricting to days with ozone below 60 ppb, each 10 ppb increase in ozone was associated with a 0.58% relative increase in daily mortality (95% CI 0.46% to 0.70%).

    “These associations remained significant when examining days below 25 μg/m3 for PM2.5 and below 60 ppb for ozone, with larger effect size estimates for both PM2.5 and ozone (RR: 1.61% [95% CI: 1.48%, 1.74%] and 0.58% [95% CI: 0.46%, 0.70%]; ARD: 2.17 [95% CI: 2.00, 2.34] and 0.74 [95% CI: 0.59, 0.90] per 1M per day)”
    Quote in the paperSubstantial claim
  • Findingown data

    No significant differences were found in the short-term associations between air pollution exposure (PM2.5 and ozone) and mortality across areas with different population density levels.

    “No significant differences were found in the short-term associations between air pollution exposure (PM2.5 and ozone) and mortality across areas with different population density levels (Figure 2).”
    Quote in the paperNot a substantial claim
  • Classified as probably not a substantial claim. 21
  • May combine two claims. 14
  • The quote only partly states this claim. 2

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Findingown data

    The baseline daily mortality rate was 137.33 per 1 million persons at risk per day for the entire year and 129.44 for the warm season.

    “The baseline daily mortality rate was 137.33 and 129.44 (per 1 million persons at risk per day) for the entire year and for the warm season, respectively.”
    Quote in the paperNot a substantial claim

  • The quote only partly states this claim.

    Findingown data

    Each 10 ppb increase in warm-season ozone exposure, adjusted by PM2.5, was associated with a 0.51% relative increase in daily mortality rate (95% CI 0.41% to 0.61%).

    “Each 10 μg/m3 and 10 ppb increase in the lag 01 day exposure for PM2.5 and warm-season ozone was associated with an increase of 1.05% (95% confidence interval [CI]: 0.95%, 1.15%) and 0.51% (0.41%, 0.61%) in the daily mortality rate.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    Of all case and control days, 93.6% had PM2.5 levels below 25 μg/m3, during which 95% of deaths occurred (21,353,817 of 22,433,862).

    “Of all case and control days, 93.6% had PM2.5 levels below 25 μg/m3, during which 95% of deaths occurred (21,353,817 of 22,433,862)”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing). The quote only partly states this claim.

    Findingown data

    During the study period, there were 22,433,862 case days and 76,143,209 control days.

    “During the study period, there were 22,433,862 million case days and 76,143,209 control days.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Findingown data

    91.1% of days had ozone levels below 60 ppb, during which 93.4% of deaths occurred (20,955,387 of 22,433,862).

    “91.1% of days had ozone levels below 60 ppb, during which 93.4% of deaths occurred (20,955,387 of 22,433,862)”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    Both PM2.5 and ozone exposure-response curves were almost linear, with no indication of a mortality risk threshold at very low concentrations.

    “Both PM2.5 and ozone exposure-responses were almost linear, with no indication of a mortality risk threshold at very low concentrations.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Findingreasoning

    The study included 39,182 zip codes, a 33% increase compared to the 26,115 zip codes with a centroid less than 50 km from a monitor.

    “Since we estimated air pollution levels everywhere in the continental US, the number of zip codes included in this study was 39,182, resulting in a 33% increase compared to the number of zip codes with a centroid <50 km from a monitor (N = 26,115).”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Findingown data

    The mean time between case and control days was 12.55 days (range 7-28 days), with minimal differences in air and dew point temperatures between case and control days (0.003°C and 0.01°C, respectively).

    “The mean time between case and control days was 12.55 days (range 7-28 days), with minimal differences in air and dew point temperatures between case and control days (0.003°C and 0.01°C, respectively).”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Findingown data

    During the study period, the mean concentrations of PM2.5 and ozone were 11.6 μg/m3 and 37.8 ppb, respectively.

    “During the study period, the mean concentrations of PM2.5 and ozone were 11.6 μg/m3 and 37.8 ppb, respectively.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    The present study found a similarly linear exposure-response relationship below 15 μg/m3 PM2.5 and a less steep slope above this level.

    “The present study found a similarly linear exposure-response relationship below 15 μg/m3 PM2.5 and a less steep slope above this level.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Findingnone given

    The study included the entire Medicare population from January 1, 2000 to December 31, 2012 residing in 39,182 zip codes.

    “The study included the entire Medicare population from January 1, 2000 to December 31, 2012 residing in 39,182 zip codes.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Study design and conductown data

    Cross-validation indicated good agreement between predicted and monitoring values for PM2.5 and ozone, including at low concentrations (R2=0.84 for PM2.5, R2=0.76 for ozone; R2=0.85 for PM2.5 <25 μg/m3; R2=0.75 for ozone <60 ppb).

    “Cross-validation indicated good agreement between predicted values and monitoring values (R2 = 0.84 for PM2.5, R2 = 0.76 for ozone) and at low concentrations (R2 = 0.85 when constraining to 24-hour PM2.5 <25 μg/m3; R2 = 0.75 when constraining to daily 8-hour maximum ozone <60 ppb).”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Study design and conductown data

    The case-crossover design individually matched potential confounding factors by month, year, and other time-invariant variables and controlled for time-varying patterns, as demonstrated by minimal differences in meteorological variables between case and control days.

    “Fifth, this study used a case-crossover design that individually matched potential confounding factors by month, year, and other time-invariant variables and controlled for time-varying patterns, as demonstrated by the minimal differences in meteorological variables between case and control days.”
    Quote in the paperSubstantial claim
    • The authors state this as an assumption: Individual-level and zip code-level covariates that do not vary day-to-day, such as age, sex, race, socioeconomic status, smoking, and other behavioral risk factors, are not confounders in the case-crossover comparison because they remain constant between case and control days.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductown data

    Splines on meteorological variables with 6 and 9 degrees of freedom yielded results with a difference of less than 5% of the standard error.

    “Splines on meteorological variables with 6 and 9 degrees of freedom yielded results with a difference of less than 5% of the standard error (Figure S1).”
    Quote in the paperNot a substantial claim

  • Classified as probably not a substantial claim. May combine two claims.

    Study design and conductcitation

    Control days were chosen on the same day of week as the case day, before and after the case day, and only in the same month as the case day to control for confounding by day of week, time trend, and seasonal/sub-seasonal patterns.

    “Control days were chosen (1) on the same day of week as the case day to control for potential confounding effect by day of week; (2) before and after the case day (bidirectional sampling) to control for time trend;9,10 and (3) only in the same month as the case day to control for seasonal and sub-seasonal patterns.9,11”
    Quote in the paperSubstantial claim0 of 3 sources checked
    • cites [9] Bateson TF Schwartz J Control for seasonal variation and time trend in case-crossover studies of acute effects of environmental exposures Epidemiology 1999 10 5 539 544 10468428

      Not checked in the free run.

    • cites [10] Maclure M Mittleman MA Should we use a case-crossover design? Annu Rev Public Health 2000 21 193 221 10884952

      Not checked in the free run.

    • cites [11] Levy D Lumley T Sheppard L Kaufman J Checkoway H Referent selection in case-crossover analyses of acute health effects of air pollution Epidemiology 2001 12 2 186 192 11246579

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductown data

    The main analysis using lag 01 day exposure yielded the lowest Akaike Information Criteria values, indicating better fit to the data.

    “The main analysis, which used the lag 01 day exposure, yielded the lowest values of the Akaike Information Criteria values, indicating better fit to the data (Table S1).”
    Quote in the paperNot a substantial claim

  • Classified as probably not a substantial claim.

    Study design and conductnone given

    The regression model included both pollutants as main effects and natural splines of air and dew point temperatures with 3 degrees of freedom to control for potential residual confounding by weather.

    “The regression model included both pollutants as main effects, and natural splines of air and dew point temperatures with 3 degrees of freedom to control for potential residual confounding by weather.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Interpretationreasoning

    The Medicare population primarily consists of individuals older than 65 years, which limits the generalizability of findings to younger populations.

    “Third, the Medicare population primarily consists of individuals older than 65 years, which limits the generalizability of findings to younger populations.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductnone given

    Medicare files do not report cause-specific mortality.

    “Fourth, Medicare files do not report cause-specific mortality.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Study design and conductown data

    Inclusion of more than 22 million deaths from 2000 to 2012 from the entire Medicare population provided large statistical power to detect differences in mortality rates in potentially vulnerable populations and to estimate mortality rates at very low PM2.5 and ozone concentrations.

    “Third, the inclusion of more than 22 million deaths from 2000 to 2012 from the entire Medicare population provided large statistical power to detect differences in mortality rates in potentially vulnerable populations and to estimate mortality rates at very low PM2.5 and ozone concentrations.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Ozone exposure was associated with multiple adverse health outcomes in a review of toxicological studies and a recent panel study.

    “Similarly, a review of toxicological studies and a recent panel study found that ozone exposure was associated with multiple adverse health outcomes.37,38”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [37] Watkinson WP Campen MJ Nolan JP Costa DL Cardiovascular and systemic responses to inhaled pollutants in rodents: effects of ozone and particulate matter Environ Health Perspect 2001 109 Suppl 4 Suppl 4 539 546 PMC1240578 11544160

      Not checked in the free run.

    • cites [38] Chuang KJ Chan CC Su TC Lee CT Tang CS The effect of urban air pollution on inflammation, oxidative stress, coagulation, and autonomic dysfunction in young adults Am J Respir Crit Care Med 2007 176 4 370 376 17463411

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Previous studies have found similar subgroup results in some subgroups.

    “Previous studies have found similar results in some subgroups.19,20”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [19] Zanobetti A Schwartz J Is there adaptation in the ozone mortality relationship: a multi-city case-crossover analysis Environ Health 2008 7 22 18513427 PMC2429903

      Not checked in the free run.

    • cites [20] Baccini M Mattei A Mealli F Bertazzi PA Carugno M Assessing the short term impact of air pollution on mortality: a matching approach Environ Health 2017 16 1 7 28187788 PMC5303266

      Not checked in the free run.

  • May combine two claims.

    Study design and conductcitation

    This is the largest analysis of daily air pollution exposure and mortality to date, with approximately 4 times the number of deaths included in a previous large study.

    “First, to the best of our knowledge, this is the largest analysis of daily air pollution exposure and mortality to date, with approximately 4 times the number of deaths included in a previous large study.4”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [4] Zanobetti A Schwartz J The effect of fine and coarse particulate air pollution on mortality: a national analysis Environmental health perspectives 2009 117 6 898 903 19590680 PMC2702403

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    One study combined exposure-response curves from 22 European cities and reported an almost linear relationship between PM2.5 and mortality.

    “One study combined exposure-response curves from 22 European cities and reported an almost linear relationship between PM2.5 and mortality.21”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [21] Samoli E Analitis A Touloumi G Estimating the exposure-response relationships between particulate matter and mortality within the APHEA multicity project Environ Health Perspect 2005 113 1 88 95 15626653 PMC1253715

      Not checked in the free run.

  • May combine two claims.

    Interpretationreasoning

    More than two-thirds of deaths in the US occur in people older than 65 years of age, and air pollution-related health risk rises with age, so the Medicare population in this study includes most cases of air pollution-induced mortality.

    “However, because more than two-thirds of deaths in the US occur in people older than 65 years of age, and air pollution-related health risk rises with age, the Medicare population in this study includes most cases of air pollution-induced mortality.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    An almost linear exposure-response curve for ozone was previously reported with no threshold or a threshold at very low concentrations.

    “An almost linear exposure-response curve for ozone was previously reported with no threshold or a threshold at very low concentrations.23”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [23] Bell ML Peng RD Dominici F The exposure-response curve for ozone and risk of mortality and the adequacy of current ozone regulations Environmental health perspectives 2006 114 4 532 536 16581541 PMC1440776

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S4 (based).

    Premisenone given

    A large population is necessary to achieve maximum accuracy and adequate statistical power for estimating the health risk of short-term exposure to air pollution for specific subgroups.

    “To estimate the health risk of short-term exposure to air pollution for specific subgroups (e.g., underrepresented minorities and those with low socioeconomic status, such as persons eligible for Medicaid), a large population is necessary to achieve maximum accuracy and adequate statistical power.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    A study from the Netherlands concluded that if an ozone threshold exists, it does so at very low levels.

    “A study from the Netherlands also concluded that if an ozone threshold exists, it does so at very low levels.24”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [24] Hoek G Schwartz JD Groot B Eilers P Effects of ambient particulate matter and ozone on daily mortality in Rotterdam, The Netherlands Archives of environmental health 1997 52 6 455 463 9541366

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Long-term risks in the same study population have been estimated elsewhere.

    “Long-term risks in the same study population have been estimated elsewhere.39”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [39] Di Q Wang Y Zanobetti A Air pollution and mortality in the Medicare population N Engl J Med 2017 376 26 2513 2522 28657878 PMC5766848

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Another multi-city study reported a linear relationship down to 2 μg/m3 PM2.5.

    “Another multi-city study reported a linear relationship down to 2 μg/m3 PM2.5.22”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [22] Schwartz J Laden F Zanobetti A The concentration-response relation between PM(2.5) and daily deaths Environmental health perspectives 2002 110 10 1025 1029 PMC1241029 12361928

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductreasoning

    Because the study used residential zip code to ascertain exposure level rather than exact home address or place of death, some measurement error is expected.

    “Second, because this study used residential zip code to ascertain exposure level rather than exact home address or place of death, some measurement error is expected.”
    Quote in the paperNot a substantial claim
31 of 31

  • The authors state this as an assumption.

    Individual-level and zip code-level covariates that do not vary day-to-day, such as age, sex, race, socioeconomic status, smoking, and other behavioral risk factors, are not confounders in the case-crossover comparison because they remain constant between case and control days.

    “Individual-level covariates and zip code-level covariates that did not vary day-to-day (e.g., age, sex, race, socioeconomic status, smoking, and other behavioral risk factors) were not considered to be confounders as they remain constant when comparing case days vs control days.”
1 of 1

Claims other papers make about this one

Each is checked against this paper’s own text: does it say what the citing paper says it does?

  • In addressing exposure to low-level concentrations, 24-h average may be another relevant measure of daily exposure, at least for certain outcomes.

    “In addressing exposure to low-level concentrations (such as concentrations below the current air quality standard), however, 24-h average may be another relevant measure of daily exposure, at least for certain outcomes (21–24).”

    From Ozone pollution: A Major health hazard worldwide (2019) · cites this paper as [22]

Self-check

Percentages, sums and reported differences re-computed from the paper’s own numbers.

Each contradiction between two passages listed here was confirmed by an independent check.

  • Case-day count is incorrectly stated in millions

    Minor

    The abstract says there were 22,433,862 million case days, but elsewhere gives the total number of deaths as 22,433,862. The word "million" makes the first count a million times larger.

1 of 1

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Related

Authors
Di, Q., Dai, L., Wang, Y., Zanobetti, A., Choirat, C., Schwartz, J. D., & Dominici, F.
Affiliations
Harvard University (US)
Corresponding author
Schwartz, Joel D.
ORCID
Venue
JAMA
Publisher
American Medical Association (AMA)
Published
2017-12-26
Volume
318
Issue
24
Pages
2446
ISSN
  • 0002-9955 (ISSN-L)
  • 0098-7484
DOI
10.1001/jama.2017.17923
PMC
PMC5783186
OpenAlex
W2779159526
Cited by
698
References
43
Citations by year
2026: 42 · 2025: 83 · 2024: 91 · 2023: 80 · 2022: 86 · 2021: 94 · 2020: 99 · 2019: 74 · 2018: 46 · 2017: 2
FWCI
32.60
Type
journal article
Language
en
Open access
Locations
  • JAMA (publishedVersion)
  • PubMed (publishedVersion)
  • Europe PMC (PubMed Central) (acceptedVersion)
  • PubMed Central (acceptedVersion)
Funders
  • National Institutes of Health
  • National Cancer Institute (R35CA197449)
  • National Institute of Environmental Health Sciences (R21ES024012, R01ES024332, P30ES000002, R01ES026217)
Topics
  • Physical Sciences › Environmental Science › Health, Toxicology and Mutagenesis › Air Quality and Health Impacts
  • Physical Sciences › Environmental Science › Health, Toxicology and Mutagenesis › Indoor Air Quality and Microbial Exposure
  • Social Sciences › Sociology and Political Science › Environmental Justice and Health Disparities
Keywords
short-term air pollution exposure, PM2.5, ozone, all-cause mortality, older adults, Medicare beneficiaries, National Ambient Air Quality Standards, air pollution health effects, United States, New York State, New Jersey
MeSH terms
Age Factors, Aged, Aged, 80 and over, Air Pollutants, Air Pollution, Environmental Exposure, Female, Medicare, Humans, Male, Mortality, Ozone, Risk, Seasons, United States, Logistic Models, Cross-Over Studies, Particulate Matter

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