Postmenopausal estrogen and increased risk of clinical osteoarthritis at the hip, hand, and knee in older women

Objective: We examined postmenopausal estrogen (PME) use and prevalence of clinical osteoarthritis (OA) at the hand, knee, and hip in 1001 community-dwelling postmenopausal women aged 43-97 years (mean age 72). Methods: OA at the hip, hand, and knee was defined by validated and standardized criteria based on pain history plus a clinical examination performed by a specially trained nurse. Results: PME, validated by examination of pills and prescriptions, had been used for at least 1 year by 638 women (63.4%) for an average duration of 14.6 (+/-10.6) years. OA prevalence was 34.5% among women who had used PME for at least 1 year and 30.9% among women who did not use PME (age adjusted p = 0.02). Knee OA prevalence did not differ by PME use (p > 0.05). A significantly larger proportion of women who used PME for at least I year had hip and hand OA compared with women not using PME (4.1% vs. 1.1%, age-adjusted p 0.002, and 15.8% vs. 13.5%, age-adjusted p = 0.02, respectively). In analyses adjusted for the potential confounding effects of age, body mass index (BMI), smoking, exercise, and type of menopause, women who used PME still were more likely to have hip OA (odds ratio [OR] = 5.03, confidence interval [CI] = 1.70-14.84, p = 0.003) and hand OA ([OR] = 1.57, CI = 1.05-2.33, P = 0.03). Among estrogen users, duration of PME use was longer for women with OA than for women without OA (16 vs. 11 median years, p = 0.01). Conclusions: PME is associated with a higher prevalence of clinical OA.