Reproductive history and postmenopausal rheumatoid arthritis among women 60 years or older: Third National Health and Nutrition Examination Survey.

OBJECTIVE: Rheumatoid arthritis, a condition of unknown etiology, has been associated with considerable costs to society. The purpose of this study is to determine whether selected reproductive history characteristics are associated with postmenopausal rheumatoid arthritis diagnosis.
METHODS: Secondary analyses were performed using cross-sectional data from the Third National Health and Nutrition Examination Survey. Of 1,892 eligible participants, 182 fulfilled the criteria for postmenopausal rheumatoid arthritis, based on self-report and the 1987 American College of Rheumatology criteria. Logistic regression models were constructed, and odds ratios (ORs) with their 95% CIs were calculated for selected reproductive history characteristics as predictors of postmenopausal rheumatoid arthritis, after adjustment for potential confounders.
RESULTS: Multivariate logistic models suggested that age at menopause was the only reproductive characteristic that was significantly associated with the outcome of interest (OR, 0.96; 95% CI, 0.93-0.99). Compared with women experiencing menopause at 50 years of age or later, those who experienced menopause before 40 years of age (OR, 2.53; 95% CI, 1.41-4.53) had increased odds of postmenopausal rheumatoid arthritis.
CONCLUSIONS: Women who experience menopause before 40 years of age seem to be at increased risk for postmenopausal rheumatoid arthritis. Conversely, age at menarche and pregnancy history may not predict rheumatoid arthritis after menopause. Further research is needed to confirm and elucidate these epidemiological findings.