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Table 2 Odds ratios for the risk of rheumatoid arthritis by categories of overall tea consumption, overall, stratified by sex, ACPA, and smoking status, and among coffee drinkers among 2237 cases and 4661 controls diagnosed with RA during 2005–2018 in Sweden

From: Is tea consumption associated with reduction of risk of rheumatoid arthritis? A Swedish case-control study

  Overall tea consumption
  Non-consumers (0 cups/day) Irregular consumers (< 1 cup/day) Regular consumers (1–2 cups/day) High consumers (≥2 cups/day)
Overall     
 Number 955/1941 453/847 388/845 441/1028
 OR crude* 0.89 (0.77–1.03) Ref 0.84 (0.71–1.00) 0.78 (0.66–0.92)
 OR adjusted± 0.82 (0.70–0.95) Ref 0.87 (0.73–1.04) 0.85 (0.71–1.01)
Female     
 Number 582/1255 358/643 288/622 359/817
 OR crude 0.82 (0.70–0.97) Ref 0.82 (0.68–1.00) 0.79 (0.65–0.95)
 OR adjusted 0.74 (0.62–0.88) Ref 0.86 (0.70–1.05) 0.86 (0.70–1.04)
Male     
 Number 373/686 95/204 100/223 82/211
 OR crude 1.09 (0.82–1.46) Ref 0.92 (0.65–1.31) 0.76 (0.52–1.10)
 OR adjusted 1.04 (0.77–1.41) Ref 0.95 (0.66–1.37) 0.79 (0.54–1.18)
ACPA positive     
 Number 637/1156 321/527 268/501 277/630
 OR crude 0.90 (0.76–1.07) Ref 0.87 (0.71–1.07) 0.71 (0.58–0.87)
 OR adjusted 0.81 (0.67–0.97) Ref 0.88 (0.71–1.09) 0.76 (0.62–0.94)
ACPA negative     
 Number 312/571 129/221 119/251 162/288
 OR crude 0.91 (0.70–1.19) Ref 0.80 (0.58–1.09) 0.97 (0.72–1.31)
 OR adjusted 0.87 (0.66–1.14) Ref 0.87 (0.63–1.19) 1.07 (0.78–1.46)
Never smokers     
 Number 290/859 164/436 142/433 213/563
 OR crude 0.91 (0.73–1.15) Ref 0.90 (0.69–1.17) 1.03 (0.81–1.32)
 OR adjusted 0.90 (0.71–1.13) Ref 0.89 (0.68–1.16) 1.05 (0.82–1.35)
Current smokers     
 Number 296/371 89/96 59/78 59/99
 OR crude 0.84 (0.60–1.18) Ref 0.84 (0.54–1.33) 0.63 (0.40–0.98)
 OR adjusted 0.82 (0.58–1.16) Ref 0.82 (0.51–1.30) 0.60 (0.38–0.95)
Coffee drinkers     
 Number 885/1769 409/768 345/762 341/759
 OR crude 0.93 (0.80–1.08) Ref 0.84 (0.70–1.00) 0.83 (0.70–0.99)
 OR adjusted 0.86 (0.74–1.00) Ref 0.86 (0.72–1.03) 0.88 (0.74–1.06)
  1. *The crude OR was based on a conditional logistic model where cases and controls were matched by age, sex, and residential area. The analyses for ACPA status were based on an unconditional logistic regression model, and the crude model was adjusted for the matching factors
  2. ±The model was additionally adjusted for coffee consumption, smoking status, alcohol, body mass index, and educational level