Daily time-series studies with air pollution exposures and myocardial (MI) outcomes: study results details
| First author and year | Exposure variable | Relative risk or rate ratio (95% CI if reported) | Exposure increase (or category) to which rate ratio refers | Lag 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 | ||
| PM10 | 1.032 (0.978 to 1.086) | 22.5 | Sum of 0–7 | ||
| O3 | 1.093 (1.011 to 1.174) | 50.23 | |||
| CO | 0.998 (0.933 to 1.066) | 1.42 | |||
| NO2 | 1.038 (0.962 to 1.114) | 54.67 | |||
| SO2 | 1.129 (1.064 to 1.194) | 10 | |||
| Lanki 200612 | PM10 | 1.003 (0.995 to 1.011) | 10 μg/m3 | 0 | No 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 |
| O3 | 0.994 (0.986 to 1.002) | 10 μg/m3 | |||
| CO | 1.025 (1 to 1.051) | 1 mg/m3 | |||
| NO2 | 0.995 (0.985 to 1.006) | 10 μg/m3 | |||
| PNC | 1.005 (0.996 to 1.015) | 10 000/cm3 | |||
| Koken 200313 | PM10 | NS (detail not reported) | 0 | Only the lag value with the strongest effect was given; therefore the effect of ozone at 1–4 days lag was not reported | |
| O3 | 0.819 (0.726 to 0.923) | 10 ppb | |||
| CO | NS (detail not reported) | ||||
| NO2 | NS (detail not reported) | ||||
| SO2 | NS (detail not reported) | ||||
| Mann 20025 | PM10 | 0.999 (0.987 to 1.011) | 10 μg/m3 | Not reported | – |
| O3 | 0.993 (0.985 to 0.997) | 10 ppb | |||
| CO | 1.035 (1.024 to 1.046) | 1 ppm | |||
| NO2 | 1.02 (1.011 to 1.03) | 10 ppb | |||
| Ye 200114 | PM10 | NS (detail not reported) | – | Not reported | Model 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 |
| O3 | NS (detail not reported) | – | |||
| CO | NS (detail not reported) | – | |||
| NO2 | 0.006 (0.003, 0.010) | Not reported | |||
| SO2 | NS (detail not reported) | – | |||
| Linn 200015 | PM10 | 1.01 (1 to 1.01) | 10 μg/m3 | 0 | Part 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 |
| O3 | 0.965 (0.899 to 1.035) | 10 ppb | |||
| CO | 1.041 (1.023 to 1.059) | 1 ppm | |||
| NO2 | 1.056 (1.005 to 1.11) | 10 ppb | |||
| Poloniecki 199716 | O3 | 0.993 (0.981 to 1.006) | 10 ppb | 1 | Further 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 |
| CO | 1.023 (1.007 to 1.04) | 1 ppm | |||
| NO2 | 1.009 (1.003 to 1.016) | 10 ppb | |||
| SO2 | 1.017 (1.007 to 1.027) | 10 ppb | |||
| Black smoke | 1.0303 (1.0092 to 1.0528) | 15 μg/m3 | |||
| Fatal events only | |||||
| Murakami 200617 | TSP (categorised) | 1.00 (reference category) | 0–99 μg/m3 | 0–1 h | The 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 200418 | PM10 | 1.01 (0.91 to 1.11) | 10 μg/m3 | Average of 0–3 | – |
| CO | 1.014 (0.995 to 1.03) | 1 ppm | |||
| SO2 | 1.03 (1.005 to 1.07) | 10 μg/m3 | |||
| Rossi 199919 | TSP | 1.10 (1.13 to 1.18) | 100 μg/m3 | Average of 3–4 | Average 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 | |||
| PM2.5 | 1.073 (1.035 to 1.114) | 10 μg/m3 | Average of 0–1 | ||
| PM10 | NS (detail not reported) | – | |||
| O3 | NS (detail not reported) | – | |||
| CO | 1.032 (1.009 to 1.055) | 1 ppm | |||
| NO2 | 1.088 (1.02 to 1.163) | 10 ppb | |||
| Zanobetti 200621 | PM2.5 | 1.052 (1.007 to 1.092) | 10 μg/m3 | Av of 0–1 | Results 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-traffic | 1.0439 (0.9688 to 1.1170) | 10.28 μg/m3 | |||
| O3 | 0.988 (0.957 to 1.017) | 10 ppb | |||
| CO | 1.124 (0.973 to 1.284) | 1 ppm | |||
| NO2 | 1.074 (1.034 to 1.104) | 10 ppb | |||
| Black carbon | 1.0834 (1.0021 to 1.1582) | 1.69 μg/m3 | |||
| Peters 200522 | PM2.5 | 1.105 (0.987 to 1.226) | 10 μg/m3 | 2 days | Strong 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 |
| O3 | 0.94 (0.895 to 0.987) | 10 μg/m3 | |||
| CO | 1.32 (0.968 to 1.801) | 1 mg/m3 | |||
| NO2 | 1.033 (0.966 to 1.104) | 10 μg/m3 | |||
| SO2 | 1.475 (1.069 to 2.005) | 10 μg/m3 | |||
| TNC | 1.04 (0.90 to 1.20) | 6400/cm3 | |||
| Ruidavets 200523 | O3 | 1.082 (0.98 to 1.166) | 10 μg/m3 | 0 | There 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 |
| NO2 | 0.922 (0.81 to 1.04) | 10 μg/m3 | |||
| SO2 | 0.98 (0.723 to 1.323) | 10 μg/m3 | |||
| Sullivan 200524 | PM2.5 | 1.01 (0.98 to 1.05) | 10 μg/m3 | Average of 0–1 h | The authors also found no effects when increasing the averaging time for the exposure variables from 1 to 24 h before the event |
| CO | 1.04 (0.99 to 1.08) | 1 ppm | |||
| SO2 | 0.97 (0.94 to 1.01) | 10 ppb | |||
| Zanobetti 200525 | PM10 | 1.007 (1.003 to 1.01) | 10 μg/m3 | 0 | Little 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 200426 | Traffic exposure | 2.73 (2.06 to 3.61) | Odds ratio for traffic exposure | Exposure 1 h before the event | – |
| D’Ippoliti 200327 | TSP | 1.028 (1.005 to 1.052) | 10 μg/m3 | Av of 0–2 | For 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 |
| CO | 1.044 (1 to 1.089) | 1 mg/m3 | |||
| NO2 | 1.293 (0.97 to 1.741) | 10 μg/m3 | |||
| SO2 | NS (detail not reported) | – | |||
| Peters 200128 | PM2.5 | 1.17 (1.035 to 1.325) | 10 μg/m3 | 2 h, hourly analysis | There 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 |
| PM10 | 1.109 (1.015 to 1.211) | 10 μg/m3 | |||
| Coarse mass | 1.16 (0.89 to 1.51) | 15 μg/m3 | |||
| O3 | 1.062 (0.965 to 1.17) | 10 ppb | |||
| CO | 1.22 (0.89 to 1.67) | 1 ppm | |||
| NO2 | 1.019 (0.934 to 1.112) | 10 ppb | |||
| SO2 | 0.98 (0.911 to 1.058) | 10 ppb | |||
| Black carbon | 1.27 (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.