Table 5

Age and sex adjusted relative risk (with 95% confidence interval (CI)) of developing rheumatoid factor positive rheumatoid arthritis in people taking ⩾4 cups of coffee a day, compared with those taking ⩽3 cups a day, in strata of different factors

  • 5-150 Each factor × coffee; likelihood ratio test based on Cox model.

  • 5-151 Adjusted for age only.