Table 5.

Analysis of benzene classified into quartiles at the census tract of the birth residence and acute leukemia by year of birth. Estimates are presented as odds ratios (OR) and 95% confidence intervals (CI). Statistically significant estimates are indicated in bold.

Year of Birth	All Years	1979–1989	1990–1994	1995–1999	2000–2004	2005–2010
Number of Children	1320	136	187	283	457	257
	OR (95% CI)	OR (95% CI)	OR (95% CI)	OR (95% CI)	OR (95% CI)	OR (95% CI)
Unadjusted
0.11-<0.39 μg/m3	Reference	Reference	Reference	Reference	Reference	Reference
0.39-<0.67 μg/m3	0.98 (0.68, 1.43)	0.70 (0.22, 2.24)	1.03 (0.38, 2.81)	0.80 (0.36, 1.76)	1.16 (0.63, 2.15)	1.37 (0.48, 3.91)
0.67-<0.91 μg/m3	1.05 (0.72, 1.51)	0.87 (0.29, 2.55)	0.83 (0.28, 2.45)	0.74 (0.36, 1.52)	0.87 (0.45, 1.68)	3.15 (1.22, 8.13)
0.91-2.03 μg/m3	1.17 (0.81, 1.68)	0.62 (0.20, 1.90)	1.30 (0.51, 3.29)	0.75 (0.35, 1.60)	1.11 (0.59, 2.07)	3.53 (1.35, 9.27)
Adjusted for Urbanization and Maternal Education
0.11-<0.39 μg/m3	Reference	Reference	Reference	Reference	Reference	Reference
0.39-<0.67 μg/m3	1.06 (0.71, 1.58)	0.53 (0.16, 1.79)	1.70 (0.54, 5.28)	0.80 (0.34, 1.86)	1.15 (0.59, 2.25)	2.22 (0.67, 7.39)
0.67-<0.91 μg/m3	1.21 (0.79, 1.87)	0.63 (0.17, 2.32)	2.16 (0.58, 8.09)	0.77 (0.34, 1.75)	0.87 (0.40, 1.88)	5.70 (1.69, 19.26)
0.91-2.03 μg/m3	1.28 (0.83, 1.97)	0.39 (0.10, 1.56)	3.17 (0.96, 10.49)	0.70 (0.30, 1.65)	1.03 (0.49, 2.17)	6.73 (1.86, 24.40)
Adjusted for Maternal Education
0.11-<0.39 μg/m3	Reference	Reference	Reference	Reference	Reference	Reference
0.39-<0.67 μg/m3	0.97 (0.67, 1.41)	0.59 (0.18, 1.91)	1.12 (0.40, 3.17)	0.78 (0.35, 1.75)	1.18 (0.63, 2.19)	1.40 (0.49, 4.01)
0.67-<0.91 μg/m3	1.07 (0.73, 1.55)	0.80 (0.26, 2.50)	1.08 (0.34, 3.48)	0.75 (0.36, 1.57)	0.90 (0.46, 1.75)	3.22 (1.24, 8.39)
0.91-2.03 μg/m3	1.13 (0.78, 1.63)	0.50 (0.15, 1.69)	1.44 (0.54, 3.89)	0.68 (0.31, 1.50)	1.07 (0.56, 2.02)	3.60 (1.35, 9.55)