Article Figures & Tables
Figures
- Figure 1:
Study design for temporal and spatial analysis of air pollutants effect on hospital admission for myocardial infarction (MI). A time-stratified case-crossover study design that evaluates the short-term (temporal) effect of O3, NO2, SO2, CO, PM10 and PM2.5 on MI. Analyses are stratified by high, medium and low levels of NO2 (spatial) as defined by land use regression estimates. Ten patients had missing data. Note: CO = carbon monoxide, NO2 = nitrogen dioxide, O3 = ozone, PM10 = particulate matter < 10 μm in diameter, PM2.5 = particulate matter < 2.5 μm in diameter, SO2 = sulfur dioxide.
- Figure 2:
Spatial distribution of nitrogen dioxide in the city of Calgary derived from land use regression estimates. Each dot represents the centroid of a 6-digit postal code with darker shading representing higher air pollution and lighter shading representing lower air pollution. Stars denote the 3 continuous monitoring stations in Calgary.
Tables
- Table 1:
Demographic characteristics of patients who were admitted to hospital for myocardial infarction in Calgary (2004–2012)
Characteristic No. (%) of patients
n = 6142Sex Male 4482 (72.9) Female 1660 (27.0) Age, yr ≤ 65 3209 (52.2) > 65 2933 (47.7) Diabetes No diabetes 4649 (75.6) Diabetes 1493 (24.3) Cigarette smoking Never smoker 2496 (40.6) Former smoker 1798 (29.2) Current smoker 1848 (30.0) Residential location* Low NO2 air pollution (1st tertile) 1660 (27.0) Medium NO2 air pollution (2nd tertile) 3088 (50.2) High NO2 air pollution (3rd tertile) 1384 (22.5) Note: NO2 = nitrogen dioxide.
↵* 10 patients with missing data.
- Table 2:
Association between air pollution and hospital admission for myocardial infarction with increases in the interquartile range of pollutants during various referent time intervals in regions with differing nitrogen dioxide pollution levels
Pollutant (median with IQR) Lag (days) OR* (95% CI) Entire study population (citywide NO2)
n = 6142Low NO2 tertile
n = 1660Medium NO2 tertile
n = 3088High NO2 tertile†
n = 1384CO (0.35, IQR 0.27–0.47) 0 index day 0.97 (0.93–1.02) 0.94 (0.88–1.01) 0.97 (0.92–1.02) 1.02 (0.95–1.09) 1-day lag 1.03 (0.98–1.08) 0.98 (0.92–1.05) 1.02 (0.97–1.07) 1.10 (1.02–1.18) 2-day lag 1.01 (0.96–1.06) 1.03 (0.96–1.10) 0.99 (0.94–1.04) 1.04 (0.97–1.12) 0- to 2-day average 1.01 (0.94–1.08) 0.97 (0.88–1.06) 0.99 (0.92–1.05) 1.09 (0.99–1.21) 0- to 4-day average 0.97 (0.90–1.05) 0.92 (0.83–1.03) 0.96 (0.88–1.03) 1.08 (0.96–1.21) NO2 (18.22, IQR 12.67–25.00) 0 index day 1.00 (0.94–1.07) 0.97 (0.89–1.06) 1.01 (0.95–1.08) 1.05 (0.95–1.15) 1-day lag 1.04 (0.97–1.11) 1.00 (0.91–1.09) 1.01 (0.94–1.07) 1.16 (1.05–1.28)† 2-day lag 1.03 (0.97–1.10) 1.03 (0.94–1.12) 1.00 (0.93–1.06) 1.11 (1.01–1.22) 0- to 2-day average 1.05 (0.96–1.14) 1.00 (0.88–1.12) 1.01 (0.92–1.10) 1.20 (1.05–1.36) 0- to 4-day average 0.98 (0.88–1.08) 0.90 (0.78–1.04) 0.93 (0.84–1.03) 1.20 (1.03–1.40)† O3 max (39.00, IQR 32.00–47.00) 0 index day 1.00 (0.95–1.06) 1.02 (0.96–1.10) 0.98 (0.93–1.03) 1.03 (0.96–1.11) 1-day lag 0.99 (0.94–1.04) 0.96 (0.90–1.03) 0.97 (0.93–1.03) 1.07 (0.99–1.15) 2-day lag 0.99 (0.94–1.04) 0.97 (0.91–1.04) 0.99 (0.94–1.04) 1.02 (0.94–1.10) 0- to 2-day average 0.99 (0.93–1.06) 0.98 (0.90–1.07) 0.97 (0.91–1.03) 1.06 (0.96–1.17) 0- to 4-day average 1.00 (0.93–1.08) 1.00 (0.90–1.11) 0.97 (0.90–1.04) 1.09 (0.97–1.22) SO2 (1.00, IQR 1.00–2.00) 0 index day 1.00 (0.96–1.05) 1.00 (0.95–1.06) 0.97 (0.93–1.01) 1.08 (1.02–1.15)† 1-day lag 1.05 (1.01–1.09) 1.03 (0.98–1.09) 1.04 (1.00–1.08) 1.10 (1.03–1.16) 2-day lag 1.04 (0.99–1.08) 1.04 (0.98–1.10) 1.03 (0.99–1.07) 1.05 (0.99–1.12) 0- to 2-day average 1.06 (1.00–1.12) 1.05 (0.97–1.14) 1.03 (0.97–1.09) 1.15 (1.06–1.25) 0- to 4-day average 1.05 (0.98–1.12) 1.05 (0.96–1.16) 1.02 (0.95–1.09) 1.10 (0.99–1.22) PM10 20.00, IQR 14.00–30.00) 0 index day 0.98 (0.95–1.02) 0.95 (0.90–1.00) 0.98 (0.95–1.02) 1.03 (0.97–1.08) 1-day lag 1.01 (0.97–1.05) 0.97 (0.92–1.02) 1.01 (0.97–1.04) 1.06 (1.01–1.12)† 2-day lag 1.01 (0.98–1.05) 0.99 (0.95–1.04) 1.00 (0.96–1.04) 1.06 (1.00–1.12) 0- to 2-day average 1.00 (0.96–1.05) 0.95 (0.89–1.01) 0.99 (0.95–1.04) 1.08 (1.01–1.16)† 0- to 4-day average 0.99 (0.94–1.05) 0.95 (0.88–1.02) 0.98 (0.93–1.04) 1.07 (0.99–1.15) PM2.5 (7.00, IQR 4.33–10.50) 0 index day 1.01 (0.98–1.05) 0.99 (0.94–1.05) 1.00 (0.97–1.04) 1.06 (1.00–1.11) 1-day lag 1.02 (0.99–1.06) 0.98 (0.93–1.03) 1.04 (1.01–1.08) 1.04 (0.99–1.10) 2-day lag 1.00 (0.96–1.04) 0.96 (0.90–1.01) 1.02 (0.97–1.06) 1.03 (0.98–1.08) 0- to 2-day average 1.02 (0.97–1.07) 0.96 (0.90–1.03) 1.03 (0.98–1.08) 1.07 (1.00–1.13) 0- to 4-day average 1.02 (0.97–1.08) 0.98 (0.91–1.06) 1.04 (0.99–1.10) 1.04 (0.96–1.12) AQHI (4.01, IQR 3.49–4.65) 0 index day 1.01 (0.96–1.05) 1.00 (0.94–1.06) 0.99 (0.95–1.04) 1.06 (0.99–1.13) 1-day lag 1.02 (0.97–1.07) 0.97 (0.91–1.03) 1.00 (0.96–1.05) 1.12 (1.05–1.20)† 2-day lag 1.01 (0.97–1.06) 0.99 (0.93–1.05) 1.00 (0.95–1.04) 1.07 (1.00–1.14) 0- to 2-day average 1.02 (0.96–1.08) 0.98 (0.90–1.06) 1.00 (0.94–1.05) 1.13 (1.04–1.23)† 0- to 4-day average 1.01 (0.94–1.08) 0.97 (0.89–1.07) 0.97 (0.91–1.04) 1.13 (1.02–1.24)† Note: CI = confidence interval, CO = carbon monoxide, IQR = interquartile range, NO2 = nitrogen dioxide, OR = odds ratio, O3 = ozone, PM10 = particulate matter < 10 μm in diameter, PM2.5 = particulate matter < 2.5 μm in diameter, SO2 = sulfur dioxide.
* Odds ratios are adjusted for temperature and relative humidity.
↵† Significant difference comparing OR in the highest NO2 tertile to the lowest NO2 tertile using the Cochran Q test.
Significant associations are bolded.
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