Table 3.

Associations between incident AF and ${\mathrm{PM}}_{2.5}$ (overall, and restricted to women with mean exposures $<10$, $<20$, and $<25{\mathrm{\mu }\mathrm{g}/\mathrm{m}}^3$) and ${\mathrm{NO}}_2$ among women enrolled in the Danish Nurse Cohort in 1993 or 1999 and followed through 2014.

	n (cases)	Model 1a	Model 2b	Model 2b${+\mathrm{PM}}_{2.5}$	Model 2b$+{\mathrm{NO}}_2$	Model 2b$+{\mathrm{L}}_{\text{den}}$
		HR (95% CI)	HR (95% CI)	HR (95% CI)	HR (95% CI)	HR (95% CI)
1-y mean
${\mathrm{NO}}_2$ per $8{\mathrm{\mu }\mathrm{g}/\mathrm{m}}^3$	23,528 (1,522)	1.03 (0.97, 1.08)	1.00 (0.94, 1.06)	0.90 (0.82, 0.98)	—c	0.96 (0.89, 1.04)
${\mathrm{PM}}_{2.5}$ per $3.9{\mathrm{\mu }\mathrm{g}/\mathrm{m}}^3$	23,528 (1,522)	1.06 (0.98, 1.14)	1.05 (0.96, 1.13)	—c	1.10 (0.98, 1.22)	1.03 (0.94, 1.12)
$<10{\mathrm{\mu }\mathrm{g}/\mathrm{m}}^3$	17,974 (262)	1.01 (0.56, 1.83)	0.99 (0.55, 1.79)	—c	—c	0.98 (0.53, 1.82)
$<20{\mathrm{\mu }\mathrm{g}/\mathrm{m}}^3$	23,202 (1,432)	1.04 (0.94, 1.14)	1.03 (0.93, 1.13)	—c	—c	1.01 (0.91, 1.12)
$<25{\mathrm{\mu }\mathrm{g}/\mathrm{m}}^3$	23,503 (1,515)	1.05 (0.97, 1.15)	1.04 (0.96, 1.14)	—c	—c	1.03 (0.93, 1.13)
3-y mean
${\mathrm{NO}}_2$ per $8{\mathrm{\mu }\mathrm{g}/\mathrm{m}}^3$	23,528 (1,522)	1.03 (0.98, 1.08)	1.00 (0.95, 1.06)	0.86 (0.78, 0.95)	—c	0.97 (0.90, 1.04)
${\mathrm{PM}}_{2.5}$ per $3.9{\mathrm{\mu }\mathrm{g}/\mathrm{m}}^3$	23,528 (1,522)	1.11 (1.01, 1.20)	1.09 (1.00, 1.20)	—c	1.21 (1.06, 1.39)	1.08 (0.97, 1.19)
$<10{\mathrm{\mu }\mathrm{g}/\mathrm{m}}^3$	15,147 (99)	0.91 (0.32, 2.62)	0.89 (0.31, 2.58)	—c	—c	0.84 (0.28, 2.52)
$<20{\mathrm{\mu }\mathrm{g}/\mathrm{m}}^3$	23,043 (1,416)	1.13 (1.01, 1.27)	1.11 (0.99, 1.25)	—c	—c	1.10 (0.97, 1.24)
$<25{\mathrm{\mu }\mathrm{g}/\mathrm{m}}^3$	23,489 (1,516)	1.12 (1.01, 1.24)	1.10 (1.00, 1.22)	—c	—c	1.09 (0.97, 1.22)
23-y mean
${\mathrm{NO}}_2$ per $8{\mathrm{\mu }\mathrm{g}/\mathrm{m}}^3$	23,528 (1,522)	1.01 (0.96, 1.06)	0.98 (0.93, 1.04)	—c	—c	0.96 (0.90, 1.04)

Note: Estimates are based on IQR increments: ${\mathrm{PM}}_{2.5}$ ($3.9{\mathrm{\mu }\mathrm{g}/\mathrm{m}}^3$), ${\mathrm{NO}}_2$, ($8.0{\mathrm{\mu }\mathrm{g}/\mathrm{m}}^3$), and ${\mathrm{L}}_{\text{den}}$ (10 dB). AF, atrial fibrillation; CI, confidence interval; HR, hazard ratio; IQR, interquartile range; ${\mathrm{L}}_{\text{den}}$, nnual mean 24-h road traffic noise levels; ${\mathrm{NO}}_2$, itrogen dioxide; ${\mathrm{PM}}_{2.5}$, articulate 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.