Final answer:
Postmenopausal women were significantly impacted by the outcomes of various health studies that examined the effects of hormone therapy (HT). The initial belief that HT could prevent cardiovascular disease and breast cancer was challenged, leading to current cautious use guidelines. Lifestyle factors were found to be more indicative of lower coronary heart disease rates than HT usage.
Step-by-step explanation:
The outcome regarding postmenopausal women in studies such as the Nurses' Health Study and the Women's Health Initiative was complex. Hormone therapy (HT), which aims to increase estrogen and progestin levels to alleviate symptoms of menopause, was initially thought to provide cardiovascular benefits and reduce the risk of breast cancer. However, a 2002 study from the Women's Health Initiative was terminated after 5.2 years due to evidence of a higher than normal risk of breast cancer in patients taking estrogen-only HT and no cardiovascular benefits. This impacted postmenopausal women by creating intense debate and leading to current guidelines which recommend HT with caution, at the lowest dose, and shortest duration to manage menopausal symptoms such as hot flashes, with regular health screenings.
Observations also suggested that after menopause, low amounts of estrogens could lead to increased prevalence of cardiovascular disease and osteoporosis in women. This has been attributed to the reduction in estrogen, which before menopause helps to reduce cholesterol in blood vessels and maintains bone density.
Lastly, the correlation between hormone replacement therapy (HRT) and lower incidence of coronary heart disease (CHD) noted in previous studies was challenged, revealing that this correlation may not be causative. Subsequent studies found that the women who took HRT and had lower CHD incidence were often from higher socio-economic backgrounds with healthier lifestyles, indicating that lifestyle factors rather than HRT were responsible for the lower CHD rates.