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