Table 4.

Association between 5-y exposure to road traffic and railway noise (per 10 dB) and stroke subtypes and fatality.

Road/Railway noise exposure and disease subgroups	Cases ($N$)	Model 2 [HR (95% CI)]a	Model 3 [HR (95% CI)]b	Model 4 [HR (95% CI)]c
Road traffic noise
All strokes	11,056	1.06 (1.03, 1.08)	1.06 (1.02, 1.07)	1.06 (1.03, 1.09)
Fatalityd
Fatal strokes	1,084	1.03 (0.95, 1.12)	1.02 (0.94, 1.11)	1.04 (0.95, 1.13)
Non-fatal strokes	7,927	1.07 (1.03, 1.10)	1.06 (1.02, 1.09)	1.06 (1.03, 1.10)
Stroke subtypes
Hemorrhagic stroke	1,232	1.03 (0.95, 1.11)	1.02 (0.95, 1.11)	1.05 (0.97, 1.14)
Ischemic stroke	6,308	1.03 (0.99, 1.06)	1.02 (0.98, 1.05)	1.05 (1.01, 1.09)
$\text{Ischemic\hspace{0.17em}}+\text{\hspace{0.17em}unspecified stroke}$	9,824	1.06 (1.03, 1.09)	1.05 (1.02, 1.08)	1.06 (1.03, 1.09)
Railway noise
All strokes	11,056	0.96 (0.91, 1.01)	0.96 (0.92, 1.01)	0.96 (0.91, 1.01)
Fatalityd
Fatal strokes	1,084	0.93 (0.79, 1.09)	0.92 (0.78, 1.08)	0.92 (0.78, 1.09)
Non-fatal strokes	7,927	0.97 (0.91, 1.03)	0.97 (0.91, 1.03)	0.97 (0.91, 1.03)
Stroke subtypes
Hemorrhagic stroke	1,232	0.92 (0.79, 1.07)	0.93 (0.80, 1.08)	0.88 (0.75, 1.03)
Ischemic stroke	6,308	0.95 (0.90, 1.01)	0.96 (0.90, 1.02)	0.95 (0.89, 1.01)
$\text{Ischemic\hspace{0.17em}}+\text{\hspace{0.17em}unspecified stroke}$	9,824	0.96 (0.92, 1.02)	0.96 (0.92, 1.01)	0.97 (0.92, 1.02)

Note: BMI, body mass index; CI, confidence interval; HR, hazard ratio; ${\mathrm{PM}}_{2.5}$, particulate matter with an aerodynamic diameter of $\le 2.5\mathrm{\mu }\mathrm{m}$ (fine particulate matter).

^aModel 2: adjusted for age, cohort (strata), sex (strata), calendar year (in 5-y periods), 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).

^bModel 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).

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

^dData on fatality were not available for the 2,045 cases in the MDC-cohort; defined as incident stroke resulting in death within $\le 28\mathrm{d}$.