Estrogen and Heart Disease
Starting in the fifth decade of life, during perimenopause and manifesting in a more pronounced way in the sixth decade when complete menopause has established itself, chronic diseases may begin to emerge in many women.
Menopause is characterized as a decrease in sex steroid hormones (testosterone estrogen, and progesterone) due to ovarian (gonadal) failure. This decrease in hormones affects hormone responsive organ systems such as the cardiovascular system, bone and the nervous system.
Women can also begin to get metabolic disorders at this time, which are responsible for the chronic diseases that can occur. These metabolic changes can include cholesterol problems, high triglycerides, blood sugar irregularities, weight gain and insulin resistance (which may lead type II diabetes). All these conditions can be prevented and treated. Lets go into a bit more detail here on each disorder and condition.
The specific changes to cholesterol during this time include increase in low-density lipoprotein (LDL), an increase in triglycerides (TG) and it decrease in high density lipoprotein (HDL). In addition, the protective effect of HDL also appears to diminish after menopause and this is thought to be because the HDL particles become smaller.
After menopause the decline in estrogen makes the blood vessel wall more susceptible to damage from oxidative stress. Oxidative stress is caused directly by the increase in LDL (especial oxidized LDL) and the decrease in the protective HDL. Other factors that increase oxidative stress are exposure to environmental pollution, smoking, poor diet and excessive emotional stress.
The use of hormone therapy is known to have a beneficial effect on cholesterol largely reversing the negative changes seen after menopause. The main benefit seen is a decrease in LDL in an increase in HDL. This was confirmed by a recent meta-analysis (comprising 16 randomized, placebo-controlled research studies conducted between 1997-2011. Where 17,971 cases were included), demonstrating that estrogen replacement therapy dramatically reduced plasma total cholesterol and LDL. The bottom line is that heart disease progresses in post-menopausal women. Also, in post menopausal women, ‘bad’ cholesterol goes up and that hormonal therapy has been shown to have a beneficial effect on cholesterol.
Stay tuned for more intersesting and up to date facts about heart disease as Dr Steve is working on his second book on reversing heart disease!