Table 3.

HRs for IHD, IHD excluding angina pectoris, and myocardial infarction in relation to transportation noise exposure during 5 y prior to the event in pooled data of nine Scandinavian cohorts ($n=\mathrm{132,801}$).

			Model 1a	Model 2b	Model 3c	Model 4d
Exposure/outcome	Cases	Person-years	HR (95% CI)	HR (95% CI)	HR (95% CI)	HR (95% CI)
Road traffic noise, per 10 dB ${\text{L}}_{\text{d}\text{e}\text{n}}$
IHD	22,459	2,263,290	1.04 (1.02, 1.06)	1.03 (1.00, 1.05)	1.02 (0.99, 1.04)	1.02 (1.00, 1.04)
IHD excluding angina pectoris	12,399	2,263,290	1.09 (1.06, 1.11)	1.06 (1.03, 1.08)	1.05 (1.02, 1.07)	1.04 (1.01, 1.07)
Myocardial infarction	7,682	2,263,290	1.04 (1.00, 1.07)	1.02 (0.99, 1.05)	1.01 (0.97, 1.04)	1.00 (0.96, 1.04)
Railway noise, per 10 dB ${\text{L}}_{\text{d}\text{e}\text{n}}$
IHD	22,459	2,263,290	1.05 (1.02, 1.07)	1.03 (1.00, 1.05)	1.02 (1.00, 1.05)	1.03 (1.00, 1.05)
IHD excluding angina pectoris	12,399	2,263,290	1.07 (1.04, 1.10)	1.05 (1.01, 1.08)	1.04 (1.00, 1.07)	1.05 (1.01, 1.08)
Myocardial infarction	7,682	2,263,290	1.06 (1.01, 1.10)	1.04 (0.99, 1.08)	1.02 (0.98, 1.06)	1.04 (0.99, 1.08)
Aircraft noise (${\text{L}}_{\text{d}\text{e}\text{n}}$)e
IHD
$\le 40$ dB ${\mathrm{L}}_{\text{den}}$	14,714	1,614,380	1 ref	1 ref	1 ref	1 ref
40.1–50 dB ${\mathrm{L}}_{\text{den}}$	501	60,863	1.04 (0.94, 1.16)	1.06 (0.96, 1.18)	1.07 (0.96-1.19)	1.07 (0.96, 1.19)
$>50$ dB ${\mathrm{L}}_{\text{den}}$	234	32,856	0.92 (0.80, 1.05)	0.95 (0.83, 1.09)	0.94 (0.82-1.08)	0.95 (0.83, 1.09)
IHD without angina pectoris
$\le 40$ dB ${\mathrm{L}}_{\text{den}}$	7,344	1,614,380	1 ref	1 ref	1 ref	1 ref
40.1–50 dB ${\mathrm{L}}_{\text{den}}$	326	60,863	1.14 (1.00, 1.30)	1.17 (1.02, 1.34)	1.18 (1.03-1.35)	1.18 (1.02, 1.35)
$>50$ dB ${\mathrm{L}}_{\text{den}}$	151	32,856	1.03 (0.87, 1.23)	1.09 (0.91, 1.29)	1.08 (0.91-1.28)	1.10 (0.92, 1.31)
Myocardial infarction
$\le 40$ dB ${\mathrm{L}}_{\text{den}}$	3,843	1,614,380	1 ref	1 ref	1 ref	1 ref
40.1–50 dB ${\mathrm{L}}_{\text{den}}$	192	60,863	1.08 (0.90, 1.28)	1.11 (0.93, 1.32)	1.12 (0.94-1.33)	1.11 (0.93, 1.33)
$>50$ dB ${\mathrm{L}}_{\text{den}}$	90	32,856	1.02 (0.82, 1.28)	1.06 (0.85, 1.33)	1.06 (0.84-1.32)	1.07 (0.86, 1.34)

Note: The HRs are estimated using Cox proportional hazards models with age as underlying timescale. BMI, body mass index; CI, confidence interval; HR, hazard ratio; IHD, ischemic heart disease; ${\mathrm{PM}}_{2.5}$, particulate matter with an aerodynamic diameter of $\le \mathrm{2.5\hspace{0.17em}}\mathrm{\mu }\mathrm{m}$ (fine particulate matter); ${\mathrm{L}}_{\text{den}}$, day-evening-night noise level based on energy equivalent noise level over a whole day with a penalty of 10 dB(A) for nighttime noise (23.00–7.00) and a penalty of 5 dB(A) for evening noise (i.e., 19.00–23.00); ref, reference.

^aAdjusted for age (by design), cohort (strata), sex (men/women), and calendar year (in 5 y periods).

^bModel 1 plus adjustment for educational level (low/medium/high), marital status (single/married), area-income (quartiles), and other noise sources (yes/no: road, railway, and aircraft noise indicators; for the three cohorts without aircraft noise information, all cohort members were assigned as no exposure).

^cModel 2 plus adjustment for smoking status (current/former/never) and physical activity (low/medium/high).

^dModel 2 plus adjustment for time-weighted ${\mathrm{PM}}_{2.5}$ exposure; 20,825 IHD, 11,245 IHD excluding angina pectoris, and 6,846 myocardial infarction cases during 2,120,816 person-years. Because the first year of ${\mathrm{PM}}_{2.5}$ modeling was 1990 but was 1975 for noise, relevant air pollution data for the model including both noise and ${\mathrm{PM}}_{2.5}$ were missing at baseline for most of the PPS cohort.

^eOnly among cohorts with aircraft noise exposure (thus excluding MDC, PPS, and GOT-MONICA) with remaining 15,499 IHD cases, 7,821 IHD without angina pectoris cases, and 4,125 myocardial infarction cases.