Table 4.

Analysis of factors associated with survival of CLL cases.^a, ^b

Variable	Value	N cases = 73	Hazard ratio (95% CI)c	DOF	P- valued
Bone marrow dose, mGye	0–21	36	1	1	0.03
	22–1,536	37	2.38 (1.11, 5.08)
Age at diagnosis, years	per 10 years increase		2.50 (1.09, 5.73)	1	0.03
Age at first exposure, years	per 10 years increase		0.41 (0.19, 0.88)	1	0.02
Absolute lymphocyte count at diagnosis, per mm3	1,533–10,000	17	1	3	<0.01
	10,000–19,000	17	0.83 (0.27, 2.56)
	20,000–39,000	19	1.79 (0.62, 5.18)
	40,000–1,089,000	20	5.02 (1.69, 14.9)
Rai stage	Stage 0–2	57	1	1	<0.01
	Stage 3–4	16	2.98 (1.32, 6.75)
Chemotherapy	No	9	1	1	0.01
	Yes	64	13.5 (1.63, 112)
Smoking	Never/ former	34	1	2	0.06
	10–20 cigarettes per day	24	0.83 (0.39, 1.78)
	More than 20 cigarettes per day	15	2.46 (1.01, 5.98)
Alcohol consumption	Never	19	1	2	0.14
	1–3 times per month	39	1.16 (0.52, 2.62)
	Once per week – every day	15	2.79 (0.88, 8.85)
Urban/rural status	Urban	59	1	2	0.20
	Rural	11	0.43 (0.17, 1.12)
	Mixed	3	1.25 (0.19, 8.38)

Abbreviations: CI, confidence interval; DOF, degrees of freedom, mGy, milligray.

^aFor 73 CLL cases with known vital status and available information on chemotherapy, smoking and alcohol consumption and urban/rural status.

^bSurvival is defined as time from diagnosis to death or end of follow-up on 10/31/2010.

^cMaximum likelihood confidence limits.

^dP-value from the likelihood ratio test comparing full model with all variables to the nested model without the variable of interest.

^eUnlagged bone marrow doses; similar risks were estimated for doses lagged by 2, 5, 10, and 15 years.