ABSTRACT
In the late 1980s and early 1990s, a number of observational and epidemiological studies
were conducted to examine potential cardioprotective effects of hormone replacement
therapy (HRT) in women. In general, several multivariate correlational studies reported a
40% to 50% reduced risk for coronary heart disease associated with HRT (1-4), even after
control for covariates such as race, height, weight, parity, smoking, and education (1).
However, in the mid-1990s Matthews et al. (5) carefully and meticulously measured
demographic and health characteristics in women prior to their initiation in HRT
programs. Results indicated that in comparison to non-HRT users, there were multiple
important psychosocial and health related variables that conferred a better cardiovascular
risk profile in HRT users prior to their use of HRT. Women who went on to get HRT were
generally better educated, had higher levels of high density lipoprotein (HDL) cholesterol,
more leisure activity, lower blood pressure and lower body weight. A subsequent clinical
trial was conducted, employing systematic manipulation of HRT in 16,608 randomly
assigned patients (8506 HRT and 8102 placebo) across 40 US clinical centers. On May 31,
2002, after approximately 5 yr of follow-up, a report in the Journal of the American
Medical Association indicated the trial was halted because significantly increased risk for
coronary heart disease and related illnesses in the HRT group (6).
