Table 3

Relative risk for RA with different combinations of mineral oil exposure and shared epitope genes
Outcome
 Exposure to mineral oil
 No shared epitope
 Any shared epitope




Cases/controls (n)a
 Relative riskb
 95% confidence interval
 Cases/controls (n)a
 Relative riskb
 95% confidence interval
RF+ RA
 No
 28/89
 1.0c
128/88
 4.7
 2.8–8.0

Yes
 17/43
 1.2
 0.6–2.5
 73/38
 6.4
 3.4–11.8
RF- RA
 No
 32/89
 1.0c
63/88
 2.1
 1.2–3.6

Yes
 10/43
 0.7
 0.3–1.5
 25/38
 2.1
 1.1–4.2
Total RA
 No
 60/89
 1.0c
191/88
 3.2
 2.1–4.9

Yes
 27/43
 0.9
 0.5–1.7
 98/38
 3.9
 2.3–6.6








Anti-CP+ RA
 No
 18/89
 1.0c
126/88
 8.0
 4.4–14.7

Yes
 13/43
 1.6
 0.7–3.7
 75/38
 11.1
 5.6–22.1
Anti-CP- RA
 No
 42/89
 1.0c
65/88
 1.5
 0.9–2.5

Yes
 14/43
 0.7
 0.3–1.5
 23/38
 1.5
 0.7–2.9
Total RA
 No
 60/89
 1.0c
191/88
 3.2
 2.1–4.9

Yes
 27/43
 0.9
 0.5–1.7
 98/38
 3.9
 2.3–6.6

Relative risk and 95% confidence interval for developing rheumatoid factor (RF)-positive rheumatoid arthritis (RA), RF- RA, antibodies to citrulline-containing peptides (anti-CP)-positive RA, anti-CP- RA and total RA for men with different combinations of exposure to mineral oil and shared epitope genes compared with men unexposed to any mineral oil and lacking shared epitope genes.

aData on the shared epitope are missing for 10 cases and 51 controls exposed to mineral oil, and for 21 cases and 176 controls unexposed to mineral oil (in comparison with Tables 1 and 2).

bRelative risk adjusted for age, residential area and smoking.

cReference group.

Sverdrup et al. Arthritis Research & Therapy 2005 7:R1296   doi:10.1186/ar1824

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