Table 4. Risk of breast cancer associated with paracetamol use.

	Cases (n=3708)	Controls (n=20 000)	Odds ratioa (95% CI)
Paracetamol use
No useb	1885	10 040
Current use	878	4943	0.90 (0.82, 1.00)
Past use	945	5017	0.97 (0.89, 1.07)
Paracetamol duration
0–0.9 years	589	2 949	1.00 (0.89, 1.12)
1–1.9 years	57	489	0.63 (0.47, 0.84)
2–3.9 years	83	531	0.81 (0.63, 1.05)
4+ years	149	974	0.77 (0.64, 0.94)
Paracetamol dosec
Up to 1 g	120	886	0.68 (0.55, 0.84)
Up to 2 g	105	785	0.73 (0.58, 0.91)
More than 2 g	64	323	1.06 (0.79, 1.41)
Paracetamol indicationc
OA	241	1 649	0.76 (0.64, 0.89)
RA	17	112	0.78 (0.45, 1.35)
Other pain	31	233	0.70 (0.47, 1.05)
Paracetamol preparationc
Paracetamol	48	354	0.69 (0.49, 0.95)
Paracetamol with codeined	128	817	0.83 (0.67, 1.02)
Paracetamol with propoxyphene	111	799	0.71 (0.57, 0.89)

OA=osteoarthritis, RA=rheumatoid arthritis.

^aAdjusted for age, calendar year, BMI, smoking, alcohol, prior benign breast disease, NSAIDs, aspirin, steroid and HRT use.

^bReference category.

^cAmong current long-term users (1 or more years of treatment duration) vs nonusers.

^dIncludes both codeine and dihydrocodeine.