Table 2: Mortality associated with age at diagnosis and other factors in pediatric patients with leukemia, 1973–2006.

CovariatesHazard ratio (HR)99% CI 𝑃

Age at diagnosis (yrs)
 <1.01.00refref
 1.0–4.00.260.22–0.30<0.0001
 5.0–9.00.330.28–0.39<0.0001
 10.0–14.00.560.48–0.66<0.0001
 15.0–19.00.890.77–1.040.05
Sex
 Male1.00refref
 Female0.860.80–0.93<0.0001
Race
 White1.00refref
 Black1.541.36–1.74<0.0001
Cell type
 T-cell1.00refref
 B-cell, B-precursor0.490.41–0.59<0.0001
Year of diagnosis
 1973–19771.00refref
 1978–19820.730.64–0.84<0.0001
 1983–19870.600.52–0.69<0.0001
 1988–19920.420.36–0.48<0.0001
 1993–19970.380.33–0.43<0.0001
 1998–20020.330.29–0.37<0.0001
 2003–20060.290.25–0.34<0.0001
No. of primaries
 1.01.00refref
 ≥2.01.751.40–2.20<0.0001
Beam radiation
 Yes1.00refref
 No0.840.77–0.92<0.0001

Notes and Abbreviations. The significance level was 0.01. CI: confidence interval.