Table 3

OR and 95% CI of ACPA-positive and ACPA-negative RA risk associated with an IQR increase in ambient air pollution in EIRA

Timing of pollution relative to onset of RAACPA-positive RA OR (95% CI)ACPA-negative RA OR (95% CI)
PM10 (2 µg/m3)SO2 (8 µg/m3)NO2 (9 µg/m3)PM10 (2 µg/m3)SO2 (8 µg/m3)NO2 (9 µg/m3)
5th Year before789 cases, 2197 controls448 cases, 2197 controls
 Model 1*0.95 (0.88 to 1.04)1.09 (0.73 to 1.64)1.06 (0.93 to 1.21)1.01 (0.91 to 1.13)1.45 (0.87 to 2.42)1.17 (1.00 to 1.37)
 Model 2†0.95 (0.87 to 1.03)0.94 (0.62 to 1.42)1.02 (0.89 to 1.16)1.01 (0.91 to 1.12)1.26 (0.75 to 2.10)1.13 (0.97 to 1.32)
 Model 3‡0.97 (0.89 to 1.06)1.01 (0.67 to 1.52)1.05 (0.92 to 1.20)1.04 (0.94 to 1.16)1.40 (0.84 to 2.33)1.19 (1.01 to 1.40)
10th Year before771 cases, 2138 controls436 cases, 2138 controls
 Model 1*0.97 (0.89 to 1.06)1.18 (0.94 to 1.48)1.08 (0.97 to 1.21)1.02 (0.92 to 1.14)1.64 (1.26 to 2.15)1.22 (1.07 to 1.39)
 Model 2†0.97 (0.89 to 1.05)1.00 (0.80 to 1.27)1.03 (0.92 to 1.15)1.02 (0.92 to 1.13)1.44 (1.10 to 1.90)1.18 (1.03 to 1.34)
 Model 3‡0.99 (0.90 to 1.08)1.03 (0.82 to 1.30)1.06 (0.95 to 1.18)1.05 (0.94 to 1.17)1.48 (1.13 to 1.95)1.22 (1.07 to 1.40)
20th Year before698 cases, 1916 controls404 cases, 1916 controls
 Model 1*1.00 (0.92 to 1.09)1.13 (1.04 to 1.23)1.03 (0.96 to 1.12)1.02 (0.91 to 1.14)1.20 (1.09 to 1.32)1.06 (0.97 to 1.17)
 Model 2†0.99 (0.90 to 1.08)1.05 (0.96 to 1.14)1.00 (0.92 to 1.08)1.01 (0.90 to 1.13)1.13 (1.02 to 1.25)1.04 (0.95 to 1.15)
 Model 3‡1.00 (0.92 to 1.10)1.06 (0.97 to 1.15)1.02 (0.94 to 1.10)1.03 (0.92 to 1.15)1.14 (1.03 to 1.26)1.06 (0.96 to 1.17)
Cumulative average991 cases, 2536 controls505 cases, 2536 controls
 Model 1*0.94 (0.86 to 1.04)1.01 (0.92 to 1.10)0.98 (0.89 to 1.08)1.00 (0.88 to 1.13)1.06 (0.96 to 1.18)1.06 (0.93 to 1.19)
 Model 2†0.94 (0.85 to 1.03)0.97 (0.89 to 1.07)0.95 (0.86 to 1.05)1.00 (0.88 to 1.13)1.04 (0.94 to 1.16)1.03 (0.91 to 1.17)
 Model 3‡0.96 (0.87 to 1.06)0.98 (0.89 to 1.07)0.97 (0.87 to 1.07)1.02 (0.90 to 1.16)1.09 (0.97 to 1.21)1.07 (0.94 to 1.21)
  • *Model 1 adjusted for age and gender.

  • †Model 2 adjusted for age, gender, smoking status.

  • ‡Model 3 adjusted for age, gender, smoking status, and educational attainment.

  • ACPA, anti-citrullinated protein antibody; NO2, nitrogen dioxide; PM10, particulate matter; RA, rheumatoid arthritis; SO2, sulphur dioxide.