Use of nonsteroidal anti-inflammatory drugs and breast cancer risk in a prospective cohort of postmenopausal women

Table 2 Associations of NSAID exposure with breast cancer risk (E3N cohort, 2004–2014)

Characteristics of exposure	No. of cases	HR¹ (95% CI)	HR² (95% CI)
Any NSAID
Never	596	1 (reference)	1 (reference)
Ever	2268	1.07 (0.98–1.18)	1.02 (0.93–1.12)
Never	596	1 (reference)	1 (reference)
Occasional	845	1.06 (0.95–1.18)	1.03 (0.92–1.15)
Recurrent	1423	1.09 (0.98–1.20)	1.01 (0.92–1.14)
Never/occasional	1441	1 (reference)	1 (reference)
Recurrent	1423	1.05 (0.97–1.13)	1.00 (0.92–1.08)
Types of NSAID
High-dose aspirin
Never/occasional use	2763	1 (reference)	1 (reference)
Recurrent use	101	1.06 (0.87–1.29)	1.02 (0.83–1.24)
Ibuprofen
Never/occasional use	2659	1 (reference)	1 (reference)
Recurrent use	205	0.93 (0.81–1.08)	0.91 (0.79–1.05)
Diclofenac
Never/occasional use	2650	1 (reference)	1 (reference)
Recurrent use	214	1.01 (0.88–1.17)	0.98 (0.85–1.14)
Piroxicam
Never/occasional use	2651	1 (reference)	1 (reference)
Recurrent use	213	1.06 (0.92–1.22)	1.03 (0.90–1.19)
Ketoprofen
Never/occasional use	2679	1 (reference)	1 (reference)
Recurrent use	185	1.06 (0.91–1.23)	1.02 (0.88–1.19)
Selective COX-2 inhibitors
Never/occasional use	2694	1 (reference)	1 (reference)
Recurrent use	170	1.02 (0.87–1.20)	0.98 (0.84–1.15)
Other NSAIDs inhibiting preferentially COX-2
Never/occasional use	2740	1 (reference)	1 (reference)
Recurrent use	124	1.04 (0.87–1.25)	1.03 (0.86–1.24)
Other NSAIDs
Never/occasional use	2547	1 (reference)	1 (reference)
Recurrent use	317	1.07 (0.95–1.21)	1.04 (0.92–1.17)

Abbreviations: CI confidence interval, COX cyclooxygenase, HR hazard ratio, NSAID nonsteroidal anti-inflammatory drug
¹Adjusted only for age (time scale)
²Adjusted for age (time scale), years of schooling (baseline), alcohol intake (time-varying), body mass index (time-varying), physical activity level (baseline), age at menarche (baseline), parity and age at first birth (baseline), lifetime use of oral contraceptives (baseline), age at menopause (baseline), history of breast cancer in first-degree relatives (baseline), personal history of benign breast disease (time-varying), lifetime use of menopausal hormone therapy (time-varying), self-report of a mammogram performed during the previous follow-up cycle (time-varying), and other types of NSAIDs (except for “Any NSAID”) (time-varying). Categories used are those displayed in Table 1

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