Skip to main content
. 2015 Dec 2;124(6):785–794. doi: 10.1289/ehp.1509777

Table 3.

Trace element and source impact IHD mortality hazard ratios per interquartile range (IQR) for alternative Cox proportional hazard model specifications.

Exposure variable (IQR) IQR CPH hazard ratio (95% CI) IQR CPH-RE hazard ratio (95% CI)
No random effects, no contextual variablesa No random effects, with contextual variablesa With random effects, no contextual variablesa With random effects and contextual variablesa
PM2.5 (3.1347 μg/m3) 1.04 (1.03, 1.05) 1.02 (1.01, 1.03) 1.05 (1.02, 1.08) 1.03 (1.00, 1.06)
As (0.00055 μg/m3) 1.03 (1.02, 1.04) 1.04 (1.02, 1.05) 1.04 (1.01, 1.06) 1.04 (1.02, 1.06)
Ca (0.04382 μg/m3) 1.02 (1.01, 1.03) 1.01 (1.00, 1.03) 1.02 (0.99, 1.05) 1.01 (0.98, 1.03)
Cl (0.03350 μg/m3) 1.03 (1.02, 1.04) 1.02 (1.01, 1.03) 1.03 (1.00, 1.05) 1.02 (1.00, 1.05)
Fe (0.04775 μg/m3) 1.03 (1.02, 1.04) 1.02 (1.01, 1.03) 1.03 (1.00, 1.05) 1.02 (1.00, 1.05)
Pb (0.00259 μg/m3) 1.03 (1.02, 1.04) 1.03 (1.02, 1.04) 1.03 (1.01, 1.04) 1.03 (1.01, 1.04)
Mn (0.00207 μg/m3) 1.00 (1.00, 1.01) 1.00 (1.00, 1.01) 1.00 (0.99, 1.01) 1.00 (0.99, 1.01)
Ni (0.00145 μg/m3) 1.01 (1.01, 1.02) 1.01 (1.00, 1.02) 1.01 (0.99, 1.03) 1.01 (0.99, 1.03)
Se (0.00081 μg/m3) 1.03 (1.02, 1.04) 1.03 (1.01, 1.04) 1.03 (1.01, 1.06) 1.03 (1.01, 1.06)
V (0.00263 μg/m3) 1.01 (1.00, 1.03) 1.00 (0.97, 1.01) 1.01 (0.97, 1.05) 1.01 (0.97, 1.05)
Si (0.04288 μg/m3) 1.01 (1.00, 1.01) 0.99 (0.98, 1.01) 1.00 (0.98, 1.03) 0.99 (0.97, 1.02)
Zn (0.01013 μg/m3) 1.02 (1.01, 1.02) 1.01 (1.01, 1.02) 1.01 (0.99, 1.02) 1.01 (0.99, 1.02)
K (0.02186 μg/m3) 1.00 (0.99, 1.02) 1.00 (0.98, 1.01) 1.00 (0.97, 1.03) 0.99 (0.96, 1.02)
Na (0.03337 μg/m3) 1.01 (1.01, 1.02) 1.01 (0.99, 1.02) 1.01 (0.99, 1.03) 1.01 (0.99, 1.04)
EC (0.25755 μg/m3) 1.04 (1.03, 1.05) 1.03 (1.01, 1.04) 1.03 (1.00, 1.06) 1.03 (1.00, 1.06)
OC (0.97547 μg/m3) 1.01 (0.99, 1.02) 0.99 (0.97, 1.00) 1.00 (0.97, 1.03) 0.99 (0.96, 1.01)
S (0.52882 μg/m3) 1.02 (1.00, 1.03) 1.05 (1.02, 1.07) 1.03 (0.99, 1.07) 1.06 (1.02, 1.11)
Biomass burning (0.54040 μg/m3) 1.00 (0.99, 1.01) 1.00 (0.99, 1.01) 1.00 (0.98, 1.02) 0.99 (0.98, 1.01)
Coal combustion (0.64208 μg/m3) 1.02 (1.02, 1.03) 1.02 (1.01, 1.03) 1.03 (1.01, 1.06) 1.03 (1.01, 1.05)
Steel industryb (0.1 μg/m3) 1.01 (0.99, 1.03) 1.01 (0.99, 1.02) 0.99 (0.95, 1.03) 1.00 (0.97, 1.03)
Oil combustion (1.08574 μg/m3) 1.01 (1.00, 1.02) 1.00 (0.99, 1.02) 1.01 (0.98, 1.04) 1.01 (0.98, 1.04)
Salt aerosols (0.10488 μg/m3) 1.02 (1.01, 1.02) 1.01 (1.00, 1.02) 1.01 (0.99, 1.03) 1.02 (0.99, 1.04)
Traffic-related (2.39980 μg/m3) 1.03 (1.02, 1.04) 1.03 (1.01, 1.05) 1.02 (0.98, 1.05) 1.03 (0.99, 1.07)
Metals-related (0.17518 μg/m3) 1.01 (1.00, 1.02) 1.01 (1.01, 1.02) 1.01 (1.00, 1.03) 1.02 (1.00, 1.03)
Crustal/soil (0.56015 μg/m3) 1.01 (1.00, 1.02) 0.99 (0.98, 1.01) 1.01 (0.98, 1.05) 1.00 (0.97, 1.03)
aAll models include 42 individual-level variables. Random-effects adjustments are at MSA-level. The six ecological contextual variables were obtained from the 1990 U.S. Census (median household income, percentage of persons > 16 years of age who were unemployed, percentage of adults with a postsecondary education, Gini coefficient of income inequality, and percent black and percent Hispanic population). bSteel increment = 0.1; steel IQR = 0.0.