Table 2

Relative risk (RR) of developing rheumatoid arthritis in relation to dietary long-chain n-3 polyunsaturated fatty acid intake in the Swedish Mammography Cohort of 32 232 women, follow-up 2003–2010

Long-chain n-3 polyunsaturated fatty acids*No of casesPerson-yearsAge-adjusted RR (95% CI)Multivariable-adjusted RR† (95% CI)
Multicategory model
 ≤0.21 g/day (median 0.15)5547 1981.001.00
 0.22–0.29 g/day3548 2770.61 (0.40 to 0.93)0.62 (0.41 to 0.95)
 0.30–0.37 g/day3951 6950.62 (0.41 to 0.94)0.63 (0.41 to 0.95)
 0.38–0.49 g/day3946 7310.70 (0.47 to 1.06)0.70 (0.46 to 1.07)
 >0.49 g/day (median 0.62)3747 2180.68 (0.45 to 1.04)0.67 (0.44 to 1.03)
  p trend0.250.30
Threshold model
 ≤0.21 g/day5547 1981.001.00
 >0.21 g/day‡150193 9220.65 (0.48 to 0.89)0.65 (0.48 to 0.90)
  • *Estimates of long-chain n-3 polyunsaturated fatty acids were based on data from the food-frequency questionnaire in 1997.

  • †Adjusted for age (continuous), cigarette smoking (never, former, current ≤10 cigarettes/day or >10 cigarettes/day), alcohol intake (never, former, current <2 drinks/week, ≥2 drinks/week), use of aspirin (yes, no) and intake energy (quintiles).

  • ‡Corresponding to more than 70 g/week of salmon or 500 g/week of cod.