Table 3.

Association between traffic noise exposure and stroke incidence.

Exposure	Cases ($N$)	Model 1 [HR (95% CI)]a	Model 2 [HR (95% CI)]b	Model 3 [HR (95% CI)]c	Model 4 [HR (95% CI)]d
Road traffic noise [years exposure, per 10 dB (${\mathrm{L}}_{\text{den}}$)]
1	11,056	1.07 (1.04, 1.09)	1.05 (1.03, 1.08)	1.05 (1.02, 1.07)	1.06 (1.03, 1.08)
5	11,056	1.07 (1.04, 1.10)	1.06 (1.03, 1.08)	1.05 (1.02, 1.07)	1.06 (1.03, 1.09)
Railway noise [years exposure, per 10 dB (${\mathrm{L}}_{\text{den}}$)]
1	11,056	0.97 (0.92, 1.02)	0.96 (0.91, 1.01)	0.96 (0.92, 1.01)	0.96 (0.91, 1.01)
5	11,056	0.97 (0.92, 1.02)	0.96 (0.91, 1.01)	0.96 (0.91, 1.01)	0.96 (0.91, 1.01)
Aircraft noise {dB [5-y exposure (${\mathrm{L}}_{\text{den}}$)]}e
$\le 40$	7,347	1.00 (Ref)	1.00 (Ref)	1.00 (Ref)	1.00 (Ref)
40.1–50	396	1.11 (0.98, 1.26)	1.12 (0.99, 1.27)	1.14 (1.00, 1.30)	1.12 (0.99, 1.28)
$>50$	158	0.91 (0.77, 1.08)	0.94 (0.79, 1.11)	0.98 (0.82, 1.17)	0.93 (0.78, 1.11)

Note: BMI, body mass index; CI, confidence interval; GOT-MONICA, Multinational Monitoring of Trends and Determinants in Cardiovascular Diseases cohort (Gothenburg); HR, hazard ratio; ${\mathrm{L}}_{\text{den}}$, 24-h annual average noise level of road traffic noise; MDC, Malmö Diet and Cancer Study; ${\mathrm{PM}}_{2.5}$, particulate matter with an aerodynamic diameter of $\le 2.5\mathrm{\mu }\mathrm{m}$ (fine particulate matter); PPS, Primary Prevention Study cohort; Ref, reference.

^aModel 1: adjusted for age, cohort (strata), sex (strata), and calendar year (in 5-y periods); and in analyses of railway noise: railway noise (yes/no).

^bModel 2: Model 1 plus adjustment for educational level (strata; low, medium, high), marital status (married/cohabiting, single), area income (quartiles), and other noise sources (road and rail (continuous), railway noise (yes/no), aircraft noise ($\le 40$, 40–50, $>50\text{\hspace{0.17em}dB}$; for the three cohorts without aircraft noise information, all cohort members were assigned to the $\le 40\text{-dB}$ group).

^cModel 3: Model 2 plus adjustment for smoking status (strata; never, former, current), physical activity (strata; low, medium, high), and BMI (${\mathrm{kg}/\mathrm{m}}^2$, continuous).

^dModel 4: Model 2 plus adjustment for time-weighted ${\mathrm{PM}}_{2.5}$ exposure (1- or 5-y). ${\mathrm{PM}}_{2.5}$ exposure history available for 10,349 cases.

^eAmong cohorts with estimation of aircraft noise exposure (thus excluding MDC, PPS, and GOT-MONICA), including 7,901 cases (7,735 in analyses including ${\mathrm{PM}}_{2.5}$; for aircraft noise analyses in Model 4, there were 7,182 cases exposed to $\le 40\text{\hspace{0.17em}dB}$, 396 cases exposed to 40.1–50 dB, and 157 cases exposed to $>50\text{\hspace{0.17em}dB}$).