Baseline characteristics by parity and association with parity (vs nulliparity) and latency (per decade increase in latency) adjusted for age at symptom onset
| Cohort characteristics at baseline | Parous women (n=1553) | Nulliparous women (n=319) | Association with parity (vs nulliparous) | Association with latency (per decade increase) |
|---|---|---|---|---|
| Median (IQR) age at IP onset (years) | 54.3 (44.6–65.2) | 54.1 (36.4–70.0) | – | – |
| n=1553 | n=319 | |||
| Median (IQR) symptom duration (months) | 6.6 (3.1–15.3) | 6.4 (2.7–13.2) | – | – |
| n=1553 | n=319 | |||
| Median (IQR) latency (years) | 26 (16–35) | – | – | – |
| n=1553 | ||||
| OR* (95% CI) | ||||
| Met 1987 ACR criteria for RA, n/N (%) | 704/1553 (45.3) | 143/319 (44.8) | 0.98 (0.76 to 1.26) | 1.06 (0.98 to 1.14) |
| Positive for RF, n/N (%) | 393/1370 (28.7) | 90/262 (34.4) | 0.76 (0.57 to 1.00) | 0.93 (0.86 to 1.02) |
| Positive for ACPA, n/N (%) | 388/1308 (29.7) | 83/249 (33.3) | 0.83 (0.62 to 1.11) | 0.95 (0.87 to 1.04) |
| Coefficient† (95% CI) | ||||
| Median (IQR) DAS28 score | 3.76 (2.82–4.82) | 3.92 (3.03–4.98) | −0.27 (−0.51 to −0.03)‡ | −0.03 (–0.10 to 0.04) |
| n=1240 | n=230 | |||
| Median (IQR) HAQ score | 0.88 (0.38–1.63) n=1537 | 0.94 (0.38–1.63) n=312 | −0.08 (−0.23 to 0.08) | 0.03 (−0.02 to 0.08) |
↵* Association of parity (vs nulliparity)/latency (per decade increase) with likelihood of meeting ACR criteria for RA or testing positive for RF or ACPA.
↵† Change in DAS28/HAQ score associated with parity (vs nulliparous)/latency (per decade increase).
↵‡ Significant association.
ACPA, anticitrullinated peptide antibodies; ACR, American College of Rheumatology; DAS28, disease activity score; HAQ, Health Assessment Questionnaire; RA, rheumatoid arthritis; RF, rheumatoid factor.