Table 4.
Exposure: Traffic volumes of nearest road () | Alternative Cox model | |||||
---|---|---|---|---|---|---|
Cox model with only individual-level covariatesa | Add group-level household incomeb to adjusted model | Add group-level smoking estimatesc to adjusted model | Exclude non-microbiologically confirmed casesa | Exclude patients who moved within Californiaa | Left-censored values: Assign zero instead of missinga | |
18,396 | 18,375 | 14,478 | 14,404 | 17,480 | 32,832 | |
Q1 (HR) | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 |
Q2 [HR (95% CI)] | 1.03 (0.86, 1.25) | 1.03 (0.86, 1.24) | 1.13 (0.91, 1.40) | 1.05 (0.87, 1.28) | 1.05 (0.87, 1.27) | 1.00 |
Q3 [HR (95% CI)] | 1.14 (0.95, 1.37) | 1.14 (0.95, 1.36) | 1.23 (1.00, 1.52) | 1.16 (0.96, 1.40) | 1.16 (0.96, 1.40) | 0.90 (0.79, 1.02) |
Q4 [HR (95% CI)] | 1.19 (0.99, 1.43) | 1.19 (0.99, 1.43) | 1.29 (1.05, 1.59) | 1.20 (1.00, 1.46) | 1.21 (1.01, 1.46) | 1.01 (0.90, 1.14) |
Q5 [HR (95% CI)] | 1.28 (1.07, 1.53) | 1.27 (1.06, 1.52) | 1.41 (1.16, 1.75) | 1.28 (1.06, 1.54) | 1.28 (1.07, 1.54) | 1.10 (0.98, 1.23) |
p-Trend | 0.002 | 0.003 | 0.004 | 0.002 | 0.04 |
Note: CI, confidence interval; HR, hazard ratio; p-Trend, the p-value for the trend across quintiles of traffic exposure; Q1–Q5, quintiles 1 through 5, where Q5 is the highest quintile of traffic exposure; vh, vehicle.
Adjusted for individual-level covariates: age, sex, race, ethnicity, foreign birth, recent immigration within 5 y prior to tuberculosis (TB) diagnosis, population density, region of residence, unemployment within one year before TB diagnosis, homeless within one year before TB diagnosis, excess recreational drug and/or alcohol use within one year before TB diagnosis, and HIV infection.
Group-level covariate: census block group median annual household income.
Group-level covariate: census tract smoking prevalence estimates.