Influence of hormone replacement therapy on C-reactive protein: population-based data

Area of Science:

• Cardiovascular Health
• Endocrinology
• Public Health

Background:

• Observational studies suggest hormone replacement therapy (HRT) reduces coronary risk, but randomized trials do not.
• A potential explanation for trial findings is that HRT's adverse effects, like elevated C-reactive protein (CRP), may counteract benefits.

Purpose of the Study:

• To investigate the association between current and past HRT use and C-reactive protein (CRP) levels.
• To explore potential mechanisms linking HRT to cardiovascular risk.

Main Methods:

• Analysis of data from the Health Survey for England 1998, a nationally representative study.
• Inclusion of 4,112 women aged 40-74, categorized as current, past, or never HRT users.
• CRP levels measured and analyzed as continuous (logged) and percentile variables, controlling for confounders.

Main Results:

• Current HRT users showed significantly higher median CRP levels (2.5 mg/l) compared to past (1.9 mg/l) and never users (1.4 mg/l).
• After adjusting for age, smoking, and body mass index, CRP remained significantly elevated only in current HRT users.
• Current users exhibited higher physical activity and alcohol consumption than recommended.

Conclusions:

• HRT use is independently associated with elevated CRP levels in a representative English population sample.
• Increased CRP may represent a plausible mechanism for adverse cardiovascular effects of HRT.
• Findings highlight the importance of considering inflammatory markers in HRT risk-benefit assessments.