Table 4.

Relative risk (RR) of invasive endometrial cancer by frequency of non-steroidal antii-nflammatory medications (NSAIDs), acetaminophen or aspirin use (1990–2004)

	# cases	Total person-years	Age-adjusted RR (95% CI)	Multivariate RR† (95% CI)
Non-aspirin NSAID use
Non-user*	372	473,427	1.0	1.0
1 day/week	41	70,508	0.91 (0.65–1.27)	0.91 (0.65–1.27)
2–3 days/week	32	48,439	0.95 (0.66–1.36)	0.89 (0.61–1.28)
4–5 days/week	12	20,395	0.78 (0.44–1.39)	0.71 (0.40–1.27)
6–7 days/week	40	50,729	1.02 (0.73–1.41)	0.78 (0.56–1.08)
P for trend			0.80	0.31
Acetaminophen use
Non-user *	370	485,037	1.0	1.0
1 day/week	68	90,751	1.17 (0.90–1.53)	1.21 (0.92–1.60)
2–3 days/week	32	47,911	0.92 (0.64–1.32)	0.86 (0.60–1.25)
4–5 days/week	16	19,153	1.08 (0.71–1.56)	0.98 (0.59–1.62)
6–7 days/week	26	30,806	1.05 (0.71–1.56)	0.86 (0.57–1.30)
P for trend			0.87	0.20
Aspirin use
Non-user *	275	367,693	1.0	1.0
1 day/week	58	91,703	0.93 (0.70–1.23)	0.96 (0.72–1.29)
2–3 days/week	33	55,373	0.80 (0.56–1.14)	0.84 (0.58–1.20)
4–5 days/week	34	38,507	1.10 (0.77–1.57)	1.08 (0.75–1.55)
6–7 days/week	126	145,634	0.98 (0.79–1.22)	0.89 (0.72–1.11)
P for trend			0.99	0.37

^†Multivariate risks from proportional hazards models are adjusted for BMI (<20 [ref], 20 to <21, 21 to <22, 22 to <23, 23 to <24, 24 to <25, 25 to <27, 27 to <29, 29 to <30, 30 to <32, 32 to <35, 35 to <40, ≥ 40), duration of oral contraceptive use (never [ref], past use <3 years, past 3–5 years, past >5 years), pack years of smoking (never, >0 to 20 years, >20 to 40 years, > 40 years), type of postmenopausal hormone (PMH) use (never used PMH, past use, current use estrogen only, current use estrogen and progesterone), age at menopause (premenopausal [ref], postmenopausal <45 years, 45–49 years, 50–52 years, ≥ 53 years), parity (1–2 [ref], 3–4, ≥ 5), age at menarche (<12, 12 [ref], >12), hypertension (present, absent), diabetes (present, absent);^‡referent group;

^*Non-users are women who did not report use on at least one day per week, and includes both current and past use.