Table 3

Daily time-series studies with air pollution exposures and myocardial (MI) outcomes: study results details

First author and yearExposure variableRelative risk or rate ratio (95% CI if reported)Exposure increase (or category) to which rate ratio refersLag for estimated effect (days unless specified)Comment
Daily time-series studies
Fatal and non-fatal events
    Cendon 200611(for ICU admissions)(units not given)NO2: cumulative effect estimate hides a significant effect at lag 0, but then reduced risk at lags 2–3 Other pollutants: effects appeared to be dominated by lag 0 effect Effects overall similar when infirmary admissions were considered (as opposed to ICU) PM10: effect similar for infirmaries but reached significance
PM101.032 (0.978 to 1.086)22.5Sum of 0–7
O31.093 (1.011 to 1.174)50.23
CO0.998 (0.933 to 1.066)1.42
NO21.038 (0.962 to 1.114)54.67
SO21.129 (1.064 to 1.194)10
    Lanki 200612PM101.003 (0.995 to 1.011)10 μg/m30No statistically significant effects at lags 1, 2, 3 days for any pollutant There was a suggestive effect of PNC, when restricting to the three cities using hospital discharge register data, which had higher power
O30.994 (0.986 to 1.002)10 μg/m3
CO1.025 (1 to 1.051)1 mg/m3
NO20.995 (0.985 to 1.006)10 μg/m3
PNC1.005 (0.996 to 1.015)10 000/cm3
    Koken 200313PM10NS (detail not reported)0Only the lag value with the strongest effect was given; therefore the effect of ozone at 1–4 days lag was not reported
O30.819 (0.726 to 0.923)10 ppb
CONS (detail not reported)
NO2NS (detail not reported)
SO2NS (detail not reported)
    Mann 20025PM100.999 (0.987 to 1.011)10 μg/m3Not reported
O30.993 (0.985 to 0.997)10 ppb
CO1.035 (1.024 to 1.046)1 ppm
NO21.02 (1.011 to 1.03)10 ppb
    Ye 200114PM10NS (detail not reported)Not reportedModel estimates do not directly indicate effect size. We can only conclude that there was some positive effect of NO2 on MI outcomes, and no significant effect of other pollutants
O3NS (detail not reported)
CONS (detail not reported)
NO20.006 (0.003, 0.010)Not reported
SO2NS (detail not reported)
    Linn 200015PM101.01 (1 to 1.01)10 μg/m30Part of a wider paper on CVD—the effects seen were not specific to MI alone: CO and NO2 were also associated with congestive heart failure, asthma and COPD, suggesting just one manifestation of an effect on susceptible subjects
O30.965 (0.899 to 1.035)10 ppb
CO1.041 (1.023 to 1.059)1 ppm
NO21.056 (1.005 to 1.11)10 ppb
    Poloniecki 199716O30.993 (0.981 to 1.006)10 ppb1Further breakdown indicated that the effects found were only significant in the cool season (Oct–Mar) SO2 was independently associated with MI in the cool season in all two-pollutant model combinations NO2, CO, black smoke were not associated in two-pollutant models, except in combination with O3
CO1.023 (1.007 to 1.04)1 ppm
NO21.009 (1.003 to 1.016)10 ppb
SO21.017 (1.007 to 1.027)10 ppb
Black smoke1.0303 (1.0092 to 1.0528)15 μg/m3
Fatal events only
    Murakami 200617TSP (categorised)1.00 (reference category)0–99 μg/m30–1 hThe effects were similar when exposure windows of up to 6 h were considered; but there was a less clear “dose–response” relationship when periods longer than 6 h were used
1.13 (1.07 to 1.20)100–149 μg/m3
1.18 (1.01 to 1.37)200–249 μg/m3
1.40 (1.00 to 1.97)⩾300 μg/m3
    Sharovsky 200418PM101.01 (0.91 to 1.11)10 μg/m3Average of 0–3
CO1.014 (0.995 to 1.03)1 ppm
SO21.03 (1.005 to 1.07)10 μg/m3
    Rossi 199919TSP1.10 (1.13 to 1.18)100 μg/m3Average of 3–4Average of 3–4 day lag best predictor; little effect of concurrent day’s exposure
Case-crossover studies
Fatal and non-fatal events
    Barnett 200620(For ages ⩾65 years)Effect estimates were in the same direction for those aged <65 years, but none were statistically significant
PM2.51.073 (1.035 to 1.114)10 μg/m3Average of 0–1
PM10NS (detail not reported)
O3NS (detail not reported)
CO1.032 (1.009 to 1.055)1 ppm
NO21.088 (1.02 to 1.163)10 ppb
    Zanobetti 200621PM2.51.052 (1.007 to 1.092)10 μg/m3Av of 0–1Results for same-day pollution levels only were in the same direction and of similar magnitude The effect of black carbon was non-significant on the same day alone, whereas CO was significantly predictive of MI on the same day (though not for days 0 and 1 averaged)
PM non-traffic1.0439 (0.9688 to 1.1170)10.28 μg/m3
O30.988 (0.957 to 1.017)10 ppb
CO1.124 (0.973 to 1.284)1 ppm
NO21.074 (1.034 to 1.104)10 ppb
Black carbon1.0834 (1.0021 to 1.1582)1.69 μg/m3
    Peters 200522PM2.51.105 (0.987 to 1.226)10 μg/m32 daysStrong effect of PM2.5 among the subgroup of never-smokers (RR = 1.20, 1.04 to 1.39 per 7.7 μg/m3) Strongest pollution effects seen at 2 days’ lag as shown There were no statistically significant effects of pollutants on any other lag days In an hourly analysis, there was no effect of PM2.5 or TNC at the hourly level at up to 6 h lag
O30.94 (0.895 to 0.987)10 μg/m3
CO1.32 (0.968 to 1.801)1 mg/m3
NO21.033 (0.966 to 1.104)10 μg/m3
SO21.475 (1.069 to 2.005)10 μg/m3
TNC1.04 (0.90 to 1.20)6400/cm3
    Ruidavets 200523O31.082 (0.98 to 1.166)10 μg/m30There was an effect for ozone at 1 day lag (p = 0.02), but not longer lags The ozone effect only was statistically significant at 0 and 1-day lag when possible coronary deaths, sudden deaths and deaths with insufficient data added to the outcome
NO20.922 (0.81 to 1.04)10 μg/m3
SO20.98 (0.723 to 1.323)10 μg/m3
    Sullivan 200524PM2.51.01 (0.98 to 1.05)10 μg/m3Average of 0–1 hThe authors also found no effects when increasing the averaging time for the exposure variables from 1 to 24 h before the event
CO1.04 (0.99 to 1.08)1 ppm
SO20.97 (0.94 to 1.01)10 ppb
    Zanobetti 200525PM101.007 (1.003 to 1.01)10 μg/m30Little effect at lag days 1 or 2 For same-day effect, a dose–response relationship was seen with steeper slope at PM10 <50 μg/m3
    Peters 200426Traffic exposure2.73 (2.06 to 3.61)Odds ratio for traffic exposureExposure 1 h before the event
    D’Ippoliti 200327TSP1.028 (1.005 to 1.052)10 μg/m3Av of 0–2For total suspended particulate and CO, the only effect was the same day; for NO2, there was no same-day effect, but a significant effect with 2 days’ lag Effects of TSP and CO were stronger in the warm season, and among those with heart conduction disorders
CO1.044 (1 to 1.089)1 mg/m3
NO21.293 (0.97 to 1.741)10 μg/m3
SO2NS (detail not reported)
    Peters 200128PM2.51.17 (1.035 to 1.325)10 μg/m32 h, hourly analysisThere was also a significantly elevated risk of MI associated with 24 h average levels lagged by 1 day (ie, levels from 24 to 48 h before the event), for PM2.5, PM10; and non-significant increased risks for coarse mass, black carbon, and NO2
PM101.109 (1.015 to 1.211)10 μg/m3
Coarse mass1.16 (0.89 to 1.51)15 μg/m3
O31.062 (0.965 to 1.17)10 ppb
CO1.22 (0.89 to 1.67)1 ppm
NO21.019 (0.934 to 1.112)10 ppb
SO20.98 (0.911 to 1.058)10 ppb
Black carbon1.27 (0.97 to 1.68)3 μg/m3
  • Estimates converted where possible to: PM10: per 10 μg/m3; PM2.5: per 10 μg/m3; O3: per 10 ppb or 10 μg/m3; CO: per ppm or mg/m3; NO2: per 10 ppb or 10 μg/m3; SO2: per 10 ppb or 10 μg/m3.

  • COPD, chronic obstructive pulmonary disease; CVD, cardiovascular disease; PNC, particle number concentration; RR, relative risk; TNC, total number concentration; TSP, total suspended particulate; SPM, suspended particulate matter.