Oral contraceptives and myocardial infarction

Article Abstract:

Early studies of women who used oral contraceptives suggested they had a much higher risk of myocardial infarction (heart attack). However, more recent studies have not found the same effect, probably because they took into account other factors such as smoking. This article reviews recent analyses and discusses the possible associations between oral contraceptive use, fat metabolism, and the incidence of heart attacks. An evaluation of data suggests that while current or past contraceptive use does not lead to an increased risk of myocardial infarction, smoking does, with consumption of more than 15 cigarettes per day leading to a 4.3-times greater risk. A past history of diabetes, hypertension, or toxemia (spread of bacterial toxins throughout the body from an infection site) also increased the risk of myocardial infarction. Current oral contraceptive use amplified the risk of myocardial infarction associated with smoking. No other interactions between myocardial infarction risk factors and myocardial infarction use were found. In addition, the levels of coronary artery disease have been stable and mortality from myocardial infarction and coronary artery disease has not increased since the introduction of oral contraceptives. Epidemiological studies have linked increased risk of coronary artery disease and myocardial infarction to decreased levels of HDL (high-density lipoprotein, a cholesterol-transporting particle in blood) and increased levels of LDL (low-density lipoprotein). Progesterone-like hormones, which were present in high doses in early forms of OCs, decrease HDL and increase LDL levels. However, these effects on lipoproteins do not appear to result in the changes suggested by epidemiological studies, as oral contraceptive users do not have increased risks of myocardial infarction or coronary artery disease. Heart attacks among contraceptive users have been linked to clot-related and not coronary artery disease-related processes. (Consumer Summary produced by Reliance Medical Information, Inc.)

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Past use of oral contraceptives and cardiovascular disease: a meta-analysis in the context of the Nurse's Health Study

Article Abstract:

Women who take oral contraceptives (OC) are at an increased risk for cardiovascular disease, and in particular, for myocardial infarction (heart attack). The risk is increased further if the woman also smokes. OCs tend to reduce levels of the ''beneficial'' high-density lipoproteins (LDL), increase the ''unfavorable'' low-density lipoproteins (LDL), alter glucose tolerance and increase blood pressure. Some studies have shown that even past users of OCs are at risk for cardiovascular events and that the risk is dependent upon how long a woman used the pill. The effect of past use of OC on cardiovascular disease was studied using the information complied by the Nurse's Health Study. In 1976, 119,061 nurses between the ages of 30 and 55 with no evidence of coronary heart disease or stroke were studied. The nurses were given questionnaires twice a year for eight years. In this group there were 380 heart attacks, 105 coronary artery disease-related deaths, 282 strokes, and 48 deaths from other cardiovascular causes. The incidence of cardiovascular disease was not affected by past OC use, the length of time the woman took the pill, or the length of time since the last pill was taken. These results suggests that the deleterious effects of OC are caused by a short-term mechanism rather than the progression of atherosclerotic disease over a long period of time. They also support the hypothesis that OC causes problems in the clotting mechanism but does not necessarily contribute to the accumulation of fatty plaques in the blood vessels (atherosclerosis). When the results of 13 studies were analyzed together, the overall relative risk of coronary heart disease among OC users was 1.01. It is concluded that the risk for coronary heart disease is not increased in past OC users. (Consumer Summary produced by Reliance Medical Information, Inc.)

Reports, Coronary heart disease, Cardiovascular research

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Myocardial infarction and stroke in young women: what is the impact of oral contraceptives?

Article Abstract:

Other cardiovascular risk factors may play a role in the increased risk of stroke and heart attack in women who use oral contraceptives. European studies found an increased risk of heart attack and stroke in users of oral contraceptives but American studies found no such risk. The increased risk of stroke seems to be similar regardless of whether a woman uses a second-generation contraceptive or a third-generation contraceptive. However, only second-generation contraceptives increase the risk of heart attack.

Stroke (Disease), Stroke

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