Table 2.

Associations between road traffic noise and incident AF in the Danish Nurse Cohort.

	$n$ (cases)	Model 1a	Model 2b	Model 2b${+\mathrm{PM}}_{2.5}$	Model 2b$+{\mathrm{NO}}_2$
		HR (95% CI)	HR (95% CI)	HR (95% CI)	HR (95% CI)
1-y mean
${\mathrm{L}}_{\text{den}}$, dB (categorical)
Low ($<48$)	Ref	Ref	Ref	Ref	Ref
Medium (48–58)	16,082 (774)	1.08 (0.95, 1.23)	1.08 (0.95, 1.24)	1.09 (0.95, 1.25)	1.12 (0.97, 1.29)
High ($>58$)	9,259 (494)	1.22 (1.06, 1.39)	1.19 (1.03, 1.37)	1.20 (1.03, 1.41)	1.31 (1.11, 1.56)
${\mathrm{L}}_{\text{den}}$, dB (continuous)
${\mathrm{L}}_{\text{den}}$ per 10 dB	23,528 (1,522)	1.05 (0.99, 1.11)	1.04 (0.97, 1.10)	1.04 (0.97, 1.11)	1.07 (0.99, 1.16)
${\mathrm{L}}_{\text{den}}>53$ per 10 dB	23,528 (1,522)	1.13 (1.02, 1.24)	1.08 (0.97, 1.20)	1.09 (0.98, 1.21)	1.09 (0.98, 1.22)
${\mathrm{L}}_{\text{den}}>58$ per 10 dB	23,528 (1,522)	1.18 (1.01, 1.38)	1.11 (0.94, 1.31)	1.11 (0.93, 1.32)	1.12 (0.94, 1.33)
3-y mean
${\mathrm{L}}_{\text{den}}$, dB (categorical)
Low ($<48$)	Ref	Ref	Ref	Ref	Ref
Medium (48–58)	16,366 (783)	1.09 (0.96, 1.24)	1.09 (0.96, 1.25)	1.09 (0.95, 1.25)	1.13 (0.98, 1.30)
High ($>58$)	9,038 (487)	1.21 (1.06, 1.39)	1.18 (1.02, 1.36)	1.17 (1.00, 1.37)	1.30 (1.09, 1.54)
${\mathrm{L}}_{\text{den}}$, dB (continuous)
${\mathrm{L}}_{\text{den}}$ per 10 dB	23,528 (1,522)	1.04 (0.99, 1.10)	1.03 (0.97, 1.09)	1.02 (0.95, 1.09)	1.07 (0.99, 1.16)
${\mathrm{L}}_{\text{den}}>53$ per 10 dB	23,528 (1,522)	1.11 (1.01, 1.23)	1.06 (0.95, 1.18)	1.07 (0.96, 1.19)	1.07 (0.96, 1.20)
${\mathrm{L}}_{\text{den}}>58$ per 10 dB	23,528 (1,522)	1.17 (1.00, 1.38)	1.10 (0.92, 1.30)	1.09 (0.92, 1.30)	1.10 (0.93, 1.32)
23-y mean
${\mathrm{L}}_{\text{den}}$, dB (categorical)
Low ($<48$)	Ref	Ref	Ref	—c	Ref
Medium (48–58)	17,051 (841)	0.98 (0.87, 1.11)	0.96 (0.85, 1.09)	—c	0.99 (0.87, 1.13)
High ($>58$)	6,939 (384)	1.04 (0.91, 1.19)	0.99 (0.86, 1.15)	—c	1.07 (0.90, 1.28)
${\mathrm{L}}_{\text{den}}$, dB (continuous)
${\mathrm{L}}_{\text{den}}$ per 10 dB	23,528 (1,522)	1.02 (0.96, 1.08)	1.00 (0.93, 1.06)	—c	1.04 (0.95, 1.13)
${\mathrm{L}}_{\text{den}}>53$ per 10 dB	23,528 (1,522)	1.07 (0.95, 1.19)	1.00 (0.88, 1.13)	—c	1.02 (0.89, 1.15)
${\mathrm{L}}_{\text{den}}>58$ per 10 dB	23,528 (1,522)	1.10 (0.90, 1.35)	1.01 (0.81, 1.26)	—c	1.01 (0.80, 1.27)

Note: AF, atrial fibrillation; CI, confidence interval; dB, decibel; HR, hazard ratio; ${\mathrm{L}}_{\text{den}}$ nnual mean 24-h road traffic noise levels; ${\mathrm{NO}}_2$, itrogen dioxide; ${\mathrm{PM}}_{2.5}$, particulate matter with an aerodynamic diameter of $<2.5{\mathrm{\mu }\mathrm{g}/\mathrm{m}}^3$.

^aModel 1, adjusted for age (underlying time) and year of cohort entry (1993/1999).

^bModel 2, $\text{Model\hspace{0.17em}}1+\text{smoking status}$, consumption of fruit, alcohol consumption, physical activity, marital status, degree of urbanization, and calendar year.

^c—, 23 mean of ${\mathrm{PM}}_{2.5}$ not available.