Table 2.

Relative Risk of Non-Hodgkin Lymphoma by Smoking Status Among Women, California Teachers Study, 1995–2007^a

Smoking Characteristic	Person-Years	Reference Category Included Household Passive Smokers			Reference Category Excluded Household Passive Smokers
		No. of Cases	RR	95% CI	No. of Cases	RR	95% CI
Smoking status
Never smoker	880,841b	374	1.00	Referent	87	1.00	Referent
Ever smoker	442,299	252	1.11	0.94, 1.30	252	1.22	0.95, 1.57
Former smoker	377,384	224	1.14	0.96, 1.35	224	1.25	0.97, 1.61
Current smoker	64,915	28	0.91	0.62, 1.34	28	1.00	0.65, 1.54
Ever-smoking dose response
Smoking intensity, cigarettes/day
<10	204,166	103	1.02	0.82, 1.27	103	1.12	0.84, 1.50
10–19	132,589	83	1.19	0.93, 1.51	83	1.30	0.96, 1.77
≥20	95,024	64	1.28	0.98, 1.68	64	1.41	1.01, 1.96
P for trend			0.04			0.02
Total no. of smoking years
≤10	132,703	53	1.06	0.79, 1.41	53	1.16	0.82, 1.65
11–20	106,546	50	1.01	0.75, 1.36	50	1.11	0.78, 1.58
>20	172,375	136	1.20	0.98, 1.47	136	1.32	1.00, 1.74
P for trend			0.09			0.06
No. of smoking pack-years
≤10	219,822	105	1.07	0.86, 1.33	105	1.17	0.88, 1.57
11–20	76,733	41	1.01	0.73, 1.40	41	1.12	0.77, 1.63
>20	107,407	91	1.32	1.04, 1.67	91	1.45	1.07, 1.96
P for trend			0.03			0.02
Age of smoking initiation, years
<18	128,612	75	1.33	1.04, 1.72	75	1.47	1.07, 2.01
≥18	283,012	164	1.04	0.87, 1.26	164	1.15	0.88, 1.50
No. of years since quitting smoking among former smokers
>20	156,813	125	1.27	1.03, 1.56	125	1.40	1.05, 1.85
11–20	106,882	54	1.11	0.83, 1.49	54	1.23	0.87, 1.73
≤10	87,618	37	0.98	0.69, 1.37	37	1.07	0.73, 1.59

Abbreviations: CI, confidence interval; RR, relative risk.

^aAll models were stratified by age at cohort entry and adjusted for race (non-Hispanic white or other) and alcohol consumption 1 year before cohort entry (0 g/day, <15 g/day, ≥15 g/day, or unknown).

^bPerson-years of follow-up for never smokers excluding household passive smokers were 255, 211.