TABLE 3.

Multivariable analysis using Poisson regression to model child's number of residences as a function of select characteristics of childhood leukemia cases enrolled in the NCCLS, 1995-2002.

Characteristics	RR	95% CI *
Child's Characteristics
Age at diagnosis (years)
0-1	1.00	Ref
2-4	1.47	1.19, 1.84
5-9	2.07	1.66, 2.60
10-14	2.61	2.06, 3.31
Race/ethnicity
White, non-Hispanic	1.00	Ref
Hispanic	0.93	0.80, 1.07
Black, non-Hispanic	0.92	0.67, 1.26
Other	1.03	0.82, 1.29
Parental Characteristics
Maternal age at child's birth (years)
< 20	1.00	Ref
20-24	0.77	0.64, 0.92
25-29	0.66	0.54, 0.80
30-34	0.55	0.44, 0.68
≥ 35	0.45	0.34, 0.60
Paternal education
≤ High school	1.00	Ref
Some college or other school	0.84	0.71, 1.01
Bachelor's degree	1.00	0.83, 1.20
Household income ($k/year)
< 15	1.00	Ref
15-29	0.90	0.75, 1.08
30-44	0.85	0.70, 1.04
45-59	0.66	0.54, 0.82
60-74	0.65	0.51, 0.84
≥ 75	0.72	0.57, 0.92
Mother moved during the year before child's birth
No	1.00	Ref
Yes	1.07	0.94, 1.22
Residential Area Characteristics
Urban/rural at diagnosis residence
Rural or town	1.00	Ref
City	1.26	1.07, 1.48
Large metro	1.09	0.94, 1.28

^*Rate ratios (RR) and 95% confidence intervals (CI) were determined using multiple linear regression adjusting for all variables in the table and assuming a Poisson distribution for number of child's residences. A scaling factor was specified to adjust for the under-dispersion of the data. Variables included in the initial model included child's age at diagnosis, child's race/ethnicity, maternal age at child's birth, maternal education, paternal education, household income at diagnosis, mother moved during the year before child's birth, maternal smoking after child's birth, residential urban/rural status at diagnosis residence and residential SES at diagnosis residence.