Table 2 Risk of rheumatoid arthritis in subjects in different alcohol consumption categories, by ACPA status and study (EIRA and CACORA)

Alcohol consumption	EIRA		CACORA
Alcohol consumption	Exp ca/co*	OR† (95% CI)	Exp ca/co*	OR† (95% CI)
RA overall
Non-drinkers	182/109	1.1 (0.8 to 1.4)	80/54	1.7 (1.1 to 2.5)
Low	674/396	1.0 (Referent)	186/215	1.0 (Referent)
Moderate	171/175	0.6 (0.4 to 0.7)	111/134	1.0 (0.7 to 1.3)
High	177/190	0.5 (0.4 to 0.6)	67/130	0.6 (0.4 to 0.9)
Trend		p<0.001		p<0.001
ACPA-positive RA
Non-drinkers	120/109	1.3 (1.0 to 1.8)	62/54	2.0 (1.3 to 3.1)
Low	410/396	1.0 (Referent)	125/215	1.0 (Referent)
Moderate	97/175	0.5 (0.4 to 0.7)	77/134	1.0 (0.7 to 1.4)
High	108/190	0.5 (0.3 to 0.6)	44/130	0.6 (0.4 to 0.9)
Trend		p<0.001		p<0.001
ACPA-negative RA
Non-drinkers	62/109	0.9 (0.6 to 1.3)	18/54	1.1 (0.6 to 2.1)
Low	264/396	1.0 (Referent)	61/215	1.0 (Referent)
Moderate	74/175	0.7 (0.5 to 0.9)	34/134	0.9 (0.6 to 1.5)
High	69/190	0.5 (0.4 to 0.7)	23/130	0.9 (0.5 to 1.5)
Trend		p<0.001		p = 0.43

*Number of exposed (Exp) cases (ca) and controls (co). †Adjusted for sex, age, smoking (never/ever) and residential area (EIRA only).
ACPA, antibodies to citrullinated peptide antigens; CACORA, Case–Control Study on Rheumatoid Arthritis; EIRA, Epidemiological Investigation of Rheumatoid Arthritis; RA, rheumatoid arthritis.