Table 4 Adjusted relative risks (95% confidence intervals) for association between overall cardiovascular mortality and more specific cardiovascular mortality causes, with background NO₂ and PM_2.5, and traffic variables: traffic intensity on nearest road in categories, indicator variable for living near a major road and traffic intensity in a 100 m buffer*

Exposure	Cardiovascular(n = 6137),RR (95% CI)	Ischaemic heart disease(n = 3521),RR (95% CI)	Cerebrovascular(n = 1175),RR (95% CI)	Heart failure(n = 422),RR (95% CI)	Cardiac dysrhythmia(n = 339),RR (95% CI)
Background concentrations
Background NO₂	1.08 (0.94 to 1.26)	0.97 (0.80 to 1.18)	1.51 (1.07 to 2.12)	1.96 (1.11 to 3.46)	1.05 (0.56 to 1.95)
Background PM_2.5	1.11 (0.93 to 1.33)	0.96 (0.75 to 1.22)	1.62 (1.07 to 2.44)	2.69 (1.37 to 5.27)	0.66 (0.30 to 1.45)
Traffic variables
Traffic intensity on nearest road
1225–10 000 mvh/24 h	0.96 (0.88 to 1.03)	0.98 (0.89 to 1.09)	0.90 (0.75 to 1.07)	0.92 (0.69 to 1.24)	1.03 (0.75 to 1.41)
>10 000 mvh/24 h	1.11 (0.99 to 1.25)	1.21 (1.04 to 1.42)	0.75 (0.55 to 2.03)	1.36 (0.90 to 2.05)	1.10 (0.66 to 1.84)
Living near a major road	1.05 (0.93 to 1.18)	1.15 (0.99 to 1.34)	0.70 (0.51 to 0.96)	0.94 (0.59 to 1.49)	1.13 (0.70 to 1.82)
Traffic intensity in 100 m buffer	1.00 (0.92 to 1.08)	1.05 (0.95 to 1.16)	0.81 (0.67 to 0.99)	0.97 (0.72 to 1.32)	1.07 (0.77 to 1.48)

*Adjusted for age, gender, smoking status and area level indicators of socio-economic status.
Relative risks were calculated for changes from the 5th to the 95th percentile: for NO₂ 30 μg/m³, for PM_2.5 10 μg/m³, and for traffic intensity in a 100 m buffer 335 000 mvh/24 h. Relative risks for traffic intensity on nearest road in categories were calculated with ⩽1225 mvh/24 h as reference category. Relative risks for living near a major road were calculated with not living near a major road as reference category. Models for traffic variables included background black smoke (1987–1996). mvh, motor vehicles; n, number of cases; NO₂, nitrogen dioxide; PM_2.5, fine particles less than 2.5 μm in diameter; RR, relative risk.