Oral contraceptives and metabolic risk markers for coronary heart disease

Disturbances in both the plasma lipid profile and in insulin handling have been implicated in the development of coronary heart disease (CHD). Estrogens and progestins are known to affect significantly both lipid and insulin metabolism. Since an increased incidence of myocardial infarction has been identified among users of oral contraceptives (OCs), the metabolic effect of these drugs on risk factors for CHD is of interest. Comparison of a range of monophasic and triphasic OCs that differ primarily in their progestin content has shown that lowering the progestin dose and using a less androgenic steroid reduce the impact on both low-density lipoproteins and high-density lipoproteins (HDLs). In terms of the HDL-2 subfraction, a lipoprotein class that may be of special relevance to the development of CHD, low-dose norethindrone and desogestrel monophasic agents had the least adverse effect. Triglyceride levels were increased by the low-dose OCs used in this study; this may be an unavoidable consequence of current trends in OC development. However, the clinical significance of these increased triglyceride levels is not clear. Glucose tolerance deteriorated similarly with all the formulations in this study, although the effect on insulin concentrations was less marked with formulations containing lower doses of progestins. It was concluded that reducing the progestin dose and changing the progestin type effectively reduce the adverse impact of OCs on metabolic risk for CHD. Although further study is recommended, the use of OC formulations without adverse effects on risk profile is indicated.