Table 4

Baseline characteristics of all participants; ACPA-positive (≥6.2 U/mL) versus ACPA-negative

All (n=40 136)ACPA-positive participants (n=401)ACPA-negative participants (n=39 735)p Value
Age (years)44 (34–51)48 (39–54)44 (34–51)<0.001
Gender (female)58%65%58%0.005
BMI (kg/m2)25 (23–28)26 (23–28)25 (23–28)0.431
Smoking: pack years0 (0–8)2 (0–13)0 (0–8)<0.001
Smoking status<0.001
 Never smoker49%39%49%
 Former smoker30%36%30%
 Current smoker21%25%21%
Alcohol (g/day)3 (0–11)4 (0–11)3 (0–11)0.571
Alcohol intake, categories0.396
 None to 5 g/day59%56%59%
 5 g/day to <10 g/day16%18%16%
 10 g/day or more25%25%25%
Fish intake (servings/month)5 (2–9)5 (2–9)5 (2–9)0.727
Sugar-sweetened soft drink intake (glasses/month)6 (0–22)5 (0–17)6 (0–22)0.053
Periodontitis (self-reported)12%14%12%0.263
Joint complaints: pain and/or stiffness in hands and/or feet21%39%21%<0.001
Joint complaints: both pain and stiffness in hands and/or feet12%29%12%<0.001
FDR with rheumatism14%18%14%0.014
Self-reported RA2%22%2%<0.001
Defined RA0%15%0%<0.001
In women (n=23 256)
Menopausal status, categories0.454
 Postmenopausal and hormone use4%3%4%
 Postmenopausal and no hormone use33%29%34%
Regular menses77%79%77%0.707
Age of menarche ≤102%3%2%0.492
  • Data are presented as median (IQR) for continuous variables and percentages for categorical variables.

  • ACPA, anticitrullinated protein antibodies; BMI, body mass index; FDR, first-degree relative; RA, rheumatoid arthritis.