Table 2.

Hazard ratios (HR) and 95% confidence intervals (95% CI) for the association between hysterectomy, oophorectomy and risk of Non-Hodgkin lymphoma (NHL)

	NHL Cases	Person-years	Age-adjusted HR (95% CI)	Multivariable-adjusted HR (95% CI)1
Hysterectomy 2
No	965	1,483,404	Ref	Ref
Yes	754	918,761	1.18 (1.04 1.34)	1.23 (1.05 1.44)
Oophorectomy 3
No	1192	1,770,900	Ref	Ref
One or partial	136	188,256	0.99 (0.82 1.19)	1.00 (0.83 1.21)
Bilateral oophorectomy	362	443,009	1.06 (0.91 1.23)	1.05 (0.90 1.22)
Age of hysterectomy (years) 2
No hysterectomy and no oophorectomy	924	1,418,101	Ref	Ref
<40	207	302,733	1.05 (0.88 1.25)	1.11 (0.90 1.36)
40–<50	377	417,411	1.30 (1.11 1.53)	1.36 (1.13 1.64)
50–<55	104	116,575	1.23 (0.97 1.56)	1.27 (0.98 1.63)
55+	66	82,041	0.99 (0.75 1.31)	1.02 (0.76 1.35)
P for trend among women with hysterectomy			0.85	0.82
Combinations of Hysterectomy/Oophorectomy status
None	924	1,418,101	Ref	Ref
No hysterectomy but one or part of ovaries taken out	33	59,242	0.85 (0.60 1.20)	0.85 (0.60 1.20)
No hysterectomy but bilateral oophorectomy	5	6,061	1.25 (0.52 3.01)	1.25 (0.52 3.00)
Hysterectomy without oophorectomy	268	352,799	1.16 (1.02 1.33)	1.22 (1.03 1.44)
Hysterectomy with one or part of ovaries taken out	103	129,014	1.22 (1.00 1.50)	1.31 (1.04 1.64)
Hysterectomy with bilateral oophorectomy	357	436,948	1.24 (1.10 1.40)	1.29 (1.09 1.52)
Collapsed combinations of hysterectomy and oophorectomy
No hysterectomy and no oophorectomy	924	1,418,101	Ref	Ref
No hysterectomy with oophorectomy	41	65,303	0.94 (0.68 1.28)	0.94 (0.68 1.28)
Hysterectomy without oophorectomy	268	352,799	1.16 (1.02 1.33)	1.21 (1.02 1.43)
Hysterectomy with oophorectomy	486	565,962	1.24 (1.11 1.38)	1.30 (1.11 1.51)

^1.In the multivariable-adjusted models, we adjusted potential confounders, including age at enrollment (in continuous), race (Asian, Black, White or other), Hispanic ethnicity (yes, no, missing), BMI (<25, 25.0 –<30, 30+ kg/m²), education (high school or less, some college/technical training, college or some post-college, and master or higher), diet quality (in continuous), smoking pack-years(never smoked, smoked <5, 5–<20, ≥ 20 pack-years), alcohol intake (non-drinker, past drinker, current and <7 drinks/wk, current and ≥7 drinks/wk), physical activity (<5, 5–<10, 10–<20, 20–<30, 30+ Metabolic equivalent (METs)/week, history of hormone use (no, estrogen only use, estrogen plus progestin use, mixed), family history of cancer (yes, no), rheumatoid arthritis ever (yes, no), or lupus (yes, no).

^2.This model additionally adjusted for oophorectomy.

^3.This model additionally adjusted for hysterectomy.