Background—It has been hypothesized that postmenopausal hormone replacement therapy (HRT) may increase levels of C-reactive protein (CRP), a marker of inflammation associated with increased risk of future cardiovascular events. However, data evaluating this hypothesis are sparse and limited to older women.

Methods and Results—CRP levels were evaluated in a cross-sectional survey of 493 healthy postmenopausal women; mean age was 51 years. Overall, median CRP levels were 2 times higher among women taking HRT than among women not taking HRT (0.27 versus 0.14 mg/dL; P=0.001). This difference was present in all subgroups evaluated, including those with no history of hypertension, hyperlipidemia, obesity, diabetes, or cigarette consumption or a family history of premature coronary artery disease (all P< 0.01). Compared with nonusers of HRT, median CRP levels were higher among women using estrogen alone (P=0.003) and women using estrogen plus progesterone (P=0.03); however, there was no significant difference in CRP levels between users of different HRT preparations. In multivariate analysis, the relationship between HRT use and CRP remained significant after control for body mass index, age, diabetes, hypertension, hyperlipidemia, alcohol use, and cigarette consumption (P=0.001).

Conclusions—In this cross-sectional survey, CRP levels were increased among apparently healthy postmenopausal women taking HRT. The potential impact of HRT on inflammatory parameters should be investigated in ongoing clinical trials.