Table 1.
Risk of Juvenile Idiopathic Arthritis (JIA) and Antinuclear antibodies (ANA) according to dietary fish intake and family history. OR and p-values from logistic regression. Classification according to ILAR criteria. The number and proportion of patients in each category
| Controls | JIA | ANA+ | |||||
|---|---|---|---|---|---|---|---|
| Multivariable logistic regression model analysis vs controls § | |||||||
| aOR (95% CI) | p | aOR (95% CI) | p | ||||
| Fish more than once a week during pregnancy | (n = 15,730) | (n = 41) | (n = 10) | ||||
| All fish | 4764 (31%) | 19 (46%) | 4.5 (1.9–10.4) | < 0.001 | 6 (60%) | 2.2 (1.4–3.6) | 0.002 |
| Fish from Baltic Sea | 791 (6%) | 4 (10%) | 2.3 (1.1–5.0) | 0.034 | 3 (30%) | 7.6 (1,9–30.2) | 0.001 |
| Fish from lake | 255 (2%) | 0 (0%) | 0 | 0.74 | 0 (0%) | 0 | 1.000 |
| Other fish | 4042 (26%) | 17 (42%) | 2.6 (1.3–5.1) | 0.009 | 5 (50%) | 5.5 (0.8–14,7) | 0.085 |
| Fish more than once a week during the baby’s first year | (n = 10,473) | (n = 31) | (n = 8) | ||||
| All fish | 4547 (43%) | 24 (77%) | 5.1 (2.1–12.4) | < 0.001 | 8 (100%) | * | 0.001 |
| Fish from Baltic Sea | 1582 (15%) | 9 (29%) | 2.3 (1.1–5.1) | 0.035 | 4 (50%) | 5.6 (1.4–22.6) | 0.014 |
| Fish from lake | 458 (4%) | 1 (3%) | 0.7 (0.097–5.2) | 0.74 | 0 (0%) | 0 | 1.000 |
| Other fish | 3387 (32%) | 17 (55%) | 2.9 (1.4–5.9) | 0.005 | 5 (63%) | 1.7 (1.1–2.7) | 0.016 |
| Family history / Heredity for JIA/RA | |||||||
| Mother with RA (n) | 157 (1%) | 1 (2%) | 2.5 (0.3–18.5) | 0.362 | |||
| Father with RA (n) | 64 (0%) | 0 (0%) | 0 | 1.000 | |||
| Siblings with JIA/RA (n) | 48 (0%) | 0 (0%) | 0 | 1.000 | |||
| 2nd degree family member with RA (n) | 1431 (9%) | 8 (20%) | 1.3 (1.0–1.5) | 0.022 | |||
| Category at Onset (ILAR) (n) | |||||||
| Oligoarticular† | 19 (46%) | ||||||
| Polyarticular‡ | 5 (12%) | ||||||
| Enthesitis-related arthritis | 4 (10%) | ||||||
| Psoriatic arthritis | 4 (10%) | ||||||
| Systemic | 5 (12%) | ||||||
| Unclassifiable | 4 (10%) | ||||||
§heredity for rheumatism (JIA or RA in first- and second-degree relatives), parity, mode of delivery, preterm birth, duration of (exclusive and total) breastfeeding introduction of formula, mother’s civil status, parental age, education, smoking habits, and whether or not the parents were born outside Sweden
*Logistic regression not possible. P-value from Chi-square, statistically significant p-values and OR in bold
†Patients with oligoarticular disease, not possible to classify as extended or persistent because of missing data
‡Patients with polyarticular disease, not possible to classify as RF positive or negative because of missing data