Table 3.
Associations of number of pregnancies, and live births with the risk of arthritis
| Model 1 | Model 2 | Model 3 | ||||
|---|---|---|---|---|---|---|
| OR (95%CI) | P for trend | OR (95%CI) | P for trend | OR (95%CI) | P for trend | |
| Number of | 0.005 | 0.546 | 0.847 | |||
| Pregnancies, times | ||||||
| ≤ 2 | 1.00 | 1.00 | 1.00 | |||
| 3 | 1.01 (0.92, 1.12) | 0.96 (0.86, 1.07) | 0.91 (0.82, 1.02) | |||
| 4 | 1.01 (0.90, 1.12) | 1.00 (0.90, 1.10) | 0.98 (0.88, 1.09) | |||
| ≥ 5 | 1.16 (1.05, 1.28) | 1.04 (0.94, 1.15) | 1.03 (0.93, 1.14) | |||
| Number of | 0.135 | 0.407 | 0.354 | |||
| Live births, times | ||||||
| ≤ 2 | 1.00 | 1.00 | 1.00 | |||
| 3 | 1.03 (0.94, 1.13) | 0.99 (0.91, 1.10) | 0.99 (0.90, 1.09) | |||
| 4 | 1.06 (0.95, 1.19) | 0.98 (0.88, 1.10) | 0.96 (0.86, 1.08) | |||
| ≥ 5 | 1.08 (0.96, 1.21) | 0.94 (0.84, 1.06) | 0.96 (0.85, 1.08) | |||
Abbreviations: OR odds ratio, CI confidence interval
Model 1: age and race/ethnicity
Model 2: model 1 variables plus education level, marital status, family poverty-income ratio, hypertension, diabetes mellitus, smoker, alcohol user
Model 3 was adjusted for model 2 variables plus body mass index, waist circumference, systolic blood pressure, diastolic blood pressure, mean energy intake, hemoglobin, fast glucose, alkaline phosphatase, total protein, sodium, phosphorus, calcium, potassium, menopause status, oral contraceptive use, use female hormones, had a hysterectomy, both ovaries removed, blood urea nitrogen, uric acid, serum creatinine, estimated glomerular filtration rate, total cholesterol, triglyceride, high-density lipoprotein-cholesterol, age at menarche, age at menopause, and fertile lifespan
*P < 0.05, **P < 0.01, ***P < 0.001