Table 2. OR of HL for tobacco smoking and age group.

	Controls n=2465	All HL, n=340			Nodular sclerosis HL, n=193
	n	n	ORa	(95% CI)	n	ORa	(95% CI)
Subjects overall
Never smoker	1095	135			83
Ever smoker	1361	203	1.33	(1.02–1.74)	108	1.16	(0.82–1.64)
Blond tobacco	572	95	1.20	(0.83–1.73)	61	1.20	(0.76–1.90)
Black tobacco	433	44	1.69	(1.03–2.79)	25	1.76	(0.92–3.38)
Ex-smoker	711	61	1.22	(0.85–1.76)	34	1.31	(0.81–2.11)
Current smoker	650	142	1.39	(1.04–1.87)	74	1.10	(0.75–1.61)
Subjects <35 years old
Never smoker *	134	88			63
Ever smoker	176	91	0.89	(0.60–1.32)	58	0.79	(0.50–1.24)
Blond tobacco	108	52	0.93	(0.57–1.54)	38	0.92	(0.52–1.62)
Black tobacco	24	12	1.15	(0.46–2.87)	9	1.22	(0.43–3.41)
Ex-smoker	32	19	1.05	(0.54–2.05)	16	1.31	(0.63–2.72)
Current smoker	144	72	0.86	(0.57–1.29)	42	0.68	(0.42–1.12)
Cigarettes per day
<8	55	31	0.98	(0.58–1.68)	22	0.97	(0.52–1.78)
≥8 and <15	51	25	0.77	(0.44–1.36)	19	0.78	(0.41–1.48)
≥15	70	31	0.84	(0.49–1.44)	13	0.51	(0.25–1.05)
P trendb				0.83			0.83
Age at start (years)
≥18	60	30	0.88	(0.52–1.51)	21	0.93	(0.50–1.73)
>15 and <18	52	32	1.07	(0.62–1.84)	19	0.83	(0.44–1.58)
⩽15	64	27	0.72	(0.41–1.26)	16	0.57	(0.29–1.12)
P trendb				0.63			0.32
Duration (years)
⩽6	63	28	0.70	(0.41–1.21)	19	0.64	(0.34–1.20)
>6 and ⩽12	62	38	1.01	(0.60–1.68)	27	1.01	(0.56–1.82)
>12	51	23	1.01	(0.53–1.95)	10	0.63	(0.26–1.50)
P trendb				0.23			0.13
Pack-years
⩽2	55	29	0.87	(0.50–1.49)	24	0.98	(0.54–1.79)
>2 and <7	59	34	0.97	(0.57–1.62)	21	0.81	(0.44–1.49)
≥7	62	25	0.77	(0.42–1.39)	10	0.43	(0.19–0.96)
P trendb				0.45			0.08
Subjects ≥35 years old
Never smoker **	961	47			20
Ever smoker	1185	112	1.96	(1.33–2.89)	50	2.17	(1.22–3.88)
Blond tobacco	464	43	1.68	(0.97–2.89)	23	2.09	(0.94–4.68)
Black tobacco	409	32	2.13	(1.13–4.01)	16	2.29	(0.89–5.90)
Ex-smoker	679	42	1.58	(0.99–2.51)	18	1.77	(0.88–3.56)
Current smoker	506	70	2.35	(1.52–3.61)	32	2.56	(1.35–4.85)
Cigarettes per day
<10	308	26	1.81	(1.07–3.06)	11	1.93	(0.87–4.24)
≥10 and <20	390	39	1.95	(1.21–3.14)	16	1.84	(0.89–3.78)
≥20	475	47	2.16	(1.35–3.48)	23	2.90	(1.45–5.82)
P trendb				0.13			0.49
Age at start (years)
≥20	416	35	1.99	(1.24–3.22)	15	2.23	(1.09–4.55)
>16 and <20	304	30	1.94	(1.16–3.25)	11	1.81	(0.81–4.06)
⩽16	462	47	1.95	(1.21–3.14)	24	2.39	(1.20–4.77)
P trendb				0.20			0.49
Duration (years)
⩽21	428	35	1.14	(0.70–1.87)	17	1.21	(0.59–2.49)
>21 and ⩽35	383	50	2.91	(1.82–4.67)	21	3.40	(1.66–6.99)
>35	371	27	3.05	(1.74–5.35)	12	4.40	(1.88–10.33)
P trendb				0.13			0.26
Pack-years
⩽11	391	26	1.14	(0.67–1.93)	12	1.18	(0.53–2.59)
>11 and <30	386	47	2.43	(1.53–3.86)	19	2.33	(1.15–4.73)
≥30	405	39	2.95	(1.77–4.91)	19	4.78	(2.23–10.26)
P trendb				0.04			0.08

HL=Hodgkin's lymphoma; OR=odds ratio.

^*Reference category for all smoking variables among subjects <35 years old.

^**Reference category for all smoking variables among subjects ≥35 years old.

^aAdjusted for age, sex, educational level, alcohol monthly consumption and centre.

^bP trend using ever-smokers only (excludes never smokers) and adjusted for the other smoking variables in the table.