Table 5.

Adjusted mortality hazard ratios (95% confidence intervals) for highest quintile traffic density in each buffer, stratified by effect modifier.

Population	$n$	$100-\mathrm{m}$ buffer [HR (95% CI)]	$200-\mathrm{m}$ buffer [HR (95% CI)]	$300-\mathrm{m}$ buffer [HR (95% CI)]	$400-\mathrm{m}$ buffer [HR (95% CI)]
Entire cohort	31,480	1.18 (0.98, 1.41)*	1.17 (1.00, 1.37)*	1.13 (0.97, 1.31)	1.06 (0.91, 1.23)
Region
San Francisco Bay Area	7,731	0.88 (0.61, 1.26)	0.99 (0.73, 1.36)	1.18 (0.87, 1.61)	0.93 (0.69, 1.25)
Central Valley	3,902	1.88 (1.09, 3.24)*	1.78 (1.12, 2.84)*	1.53 (1.02, 2.31)	1.27 (0.87, 1.87)
Southern California	17,935	1.19 (0.94, 1.50)*	1.13 (0.92, 1.39)	1.04 (0.85, 1.26)	1.07 (0.87, 1.30)
p-Interaction	—	0.03	0.19	0.52	0.85
Exclusive DOT
No	13,098	1.21 (0.86, 1.70)*	1.35 (1.00, 1.82)*	1.47 (1.10, 1.96)*	1.39 (1.06, 1.83)*
Yes	18,207	1.12 (0.91, 1.40)	1.03 (0.86, 1.24)	0.93 (0.78, 1.12)	0.85 (0.71, 1.01)
p-Interaction	—	0.21	0.29	0.01	0.005
Smoking prevalence
Low	12,861	1.38 (1.04, 1.84)*	1.48 (1.16, 1.89)*	1.41 (1.11, 1.79)*	1.28 (1.01, 1.62)*
High	12,241	1.14 (0.83, 1.55)	1.12 (0.86, 1.44)	1.03 (0.81, 1.31)	0.93 (0.73, 1.17)
p-Interaction	—	0.40	0.003	0.08	0.32
Age, y
0–64	24,154	1.05 (0.77, 1.41)	1.11 (0.91, 1.53)	0.94 (0.73, 1.21)	0.87 (0.68, 1.11)
$\ge 65$	7,326	1.24 (0.98, 1.55)*	1.17 (0.96, 1.42)	1.19 (0.99, 1.43)*	1.14 (0.96, 1.37)
p-Interaction	—	0.63	0.84	0.45	0.47
Enrollment Year
2000–2003	11,392	1.01 (0.77, 1.34)	1.04 (0.81, 1.33)	1.05 (0.83, 1.34)	0.98 (0.77, 1.24)
2004–2006	7,140	1.68 (1.14, 2.48)*	1.40 (1.01, 1.95)*	1.29 (0.94, 1.75)	1.01 (0.76, 1.36)
2007–2009	6,793	0.99 (0.67, 1.46)	1.31 (0.95, 1.82)	1.37 (0.99, 1.88)	1.35 (0.99, 1.85)
2010–2012	6,155	1.33 (0.83, 2.12)	1.05 (0.73, 1.50)	0.90 (0.65, 1.25)	1.00 (0.73, 1.38)
p-Interaction	—	0.07	0.69	0.84	0.44
HIV
No	29,929	1.26 (1.04, 1.52)*	1.19 (1.01, 1.40)*	1.15 (0.98, 1.34)*	1.06 (0.91, 1.23)
Yes	1,551	0.60 (0.32, 1.14)	0.95 (0.55, 1.63)	0.88 (0.51, 1.51)	1.09 (0.59, 1.99)
p-Interaction	—	0.053	0.31	0.51	0.74

Note: CI, confidence interval; DOT, directly observed tuberculosis (TB) treatment; HR, hazard ratio. Adjusted for age, sex, race, ethnicity, foreign birth, recent immigration within 5 y before TB diagnosis, population density, region, unemployment 1 y before TB diagnosis, homeless within one year before TB diagnosis, excess alcohol and/or recreational drug use within one year before TB diagnosis, and HIV infection. The HR represents the highest quintile traffic density compared with the lowest quintile traffic density in each effect modifier level and buffer.

^*A statistically significant trend ($p-\text{trend}<0.05$) exists across quintiles.