Table 3.

Odds ratios for the risk of developing rheumatoid arthritis by categories of tea consumption, stratified by type of tea among 2237 cases and 4661 controls, included in the EIRA study 2005–2018

	Numbers	Crude OR*	Adjusted OR±
Herbal tea (cups/day)
No consumers (0)	1923/3959	0.94 (0.77–1.15)	0.86 (0.70–1.05)
Irregular consumers (< 1)	167/332	Ref	Ref
Regular consumers (≥1)	147/370	0.78 (0.59–1.03)	0.77 (0.58–1.02)
Tea (cups/day)
No consumers (0)	1048/2150	0.89 (0.78–1.03)	0.83 (0.71–0.96)
Irregular consumers (< 1)	432/815	Ref	Ref
Regular consumers (1–< 2)	397/848	0.86 (0.72–1.02)	0.90 (0.76–1.08)
High consumers (≥2)	360/848	0.78 (0.66–0.94)	0.85 (0.71–1.03)

*The crude OR was based on a conditional logistic model where cases and controls were matched by age, sex, and residential area

^±The model was additionally adjusted for coffee consumption, smoking status, alcohol, body mass index, and educational level