Nitrogen dioxide levels estimated from land use regression models several years apart and association with mortality in a large cohort study

Table 4 Adjusted hazard ratios (HR) of the association between nitrogen dioxide (NO ₂ ) estimated from the 1995/96 and the 2007 LUR models and natural mortality. Rome 2001-2006

	1995/96 LUR model					2007 LUR model
	Population	HR	95%CI			Population	HR	95%CI
Quintiles of NO₂
1	136,842	1.00				136,841	1.00
2	136,840	1.04	1.01	-	1.07	136,842	1.06	1.03	-	1.09
3	136,885	1.08	1.05	-	1.11	136,846	1.08	1.04	-	1.11
4	136,829	1.08	1.04	-	1.11	136,843	1.09	1.06	-	1.13
5	136,808	1.10	1.06	-	1.13	136,832	1.11	1.07	-	1.14
p-trend^§		<0.001					<0.001
Categories of NO₂
<=35 μg/m³	44,357	1.00				103,836	1.00
35-45 μg/m³	217,880	1.05	1.01	-	1.10	246,148	1.07	1.04	-	1.10
45-50 μg/m³	259,318	1.10	1.05	-	1.14	181,160	1.10	1.07	-	1.14
>50 μg/m³	162,649	1.13	1.08	-	1.18	153,060	1.12	1.08	-	1.16
p-trend^§		<0.001					<0.001
Effect per linear increase in NO2
per 10 μg/m³		1.06	1.04	-	1.08		1.04	1.03	-	1.05
per IQ range*		1.04	1.03	-	1.06		1.04	1.03	-	1.06

HR, Hazard Ratios, adjusted for age, sex, marital status, place of birth, education, occupation, and area-based socioeconomic position.
* The IQ ranges are 7.28 μg/m³ and 10.37 μg/m³, in 1995/96 and in 2007, respectively.
§ Wald test.

ISSN: 1476-069X