Risk factors for cardiovascular disease in women: relationship to lipid peroxidation and oxidative stress.

Many risk factors that promote cardiovascular disease (CVD) have been identified. These include hypertension, hypercholesterolemia, diabetes, decreased estrogen in post-menopausal women, increased homocysteine, and cigarette smoking. It has recently become clear that a mechanism common to these risk factors is oxidative stress. CVD risk factors specific to women are parity, oophorectomy, pre-eclampsia, and menopause. There are several proposed mechanisms to explain these women-specific associations, such as reduced lifetime exposure to estrogen and insulin resistance, but the underlying mechanism is still unclear. One fact that did not receive much attention is the role of the oxidation hypothesis in these reproductive factors-CVD associations. In fact, pregnant, oophorectomized, and post-menopausal women exhibit higher levels of lipid peroxidation than non-pregnant, non-oophorectomized and pre-menopausal women, respectively. We propose that the increased levels of lipid peroxidation during these states are responsible, at least in part, for their increased risk of CVD. This review extends the concept of the oxidation hypothesis of CVD to reproductive risk factors in women. It also addresses the potential role of oxidative stress in the hyperthyroidism-CVD relationship, as hyperthyroidism is a common disorder that most frequently occurs in women. We also discuss how screening human populations for reactive oxygen species (ROS) levels could help identify groups with a high level of ROS that may be at risk of developing CVD.