Coronary heart disease and stroke are the leading causes of death in women, according to the American Heart Association. Excess triglyceride levels are linked to coronary artery disease. While triglyceride levels are affected by diet and exercise, estrogen also plays a role, increasing triglyceride levels. If you are taking estrogen as part of a birth control pill, or as part of hormone replacement therapy for menopausal symptoms, your triglyceride levels could be adversely affected.
Effects
Estrogen affects the concentration of various lipoproteins in your blood. For example, estrogen increases the levels of HDL, the good cholesterol, and it decreases the level of LDL or bad cholesterol. This appears to indicate that estrogen would be beneficial. However, estrogen also increases triglyceride levels. A 1991 study led by Dr. Brian W. Walsh and reported in the "New England Journal of Medicine" showed that doses of 0.625 mg and 1.25 mg of estrogen increased plasma triglyceride levels by 24 percent and 42 percent, respectively.
Considerations
Estrogen levels naturally vary during a woman's menstrual cycle. During the follicular phase, which starts on the first day of menstruation, when she begins bleeding and ends when she ovulates, estrogen levels are low. During the luteal phase, which begins the day after ovulation and continues to the day before bleeding, estrogen levels are high. As a consequence, during the luteal phase, LDL and LDL/HDL ratios are lower whereas during the follicular phase, LDL and LDL/HDL ratios are higher.
Because estrogen also affects triglyceride levels, it is expected that during the luteal phase, triglyceride levels would be higher than during the follicular phase. Therefore, these fluctuations need to be considered when screening and monitoring plasmid lipoprotein levels in women, whether or not they take estrogen supplements, as different phases of the menstrual cycle may affect test results.
Significance
Because excess triglyceride levels are linked to coronary heart disease, baseline triglyceride levels should be established before estrogen is prescribed. Women with hypertriglyceridemia, excess triglycerides in their blood plasma, are advised not to begin any estrogen regimen as even a moderate increase in triglycerides caused by addition of estrogen could cause significant heat problems.
Theories/Speculation
Hypertriglyceridemia, excess triglycerides, caused by taking estrogen supplements may not have the same adverse effects on women, as hypertriglyceridemia caused by obesity or diabetes. Women taking oral estrogen show an increased elimination of very low density lipoprotein or VLDL in the liver. This accelerated increase of VLDL elimination results in reduced plaque formation in the arteries. Thus, although taking estrogen pills may increase triglyceride levels, the results of the increased triglyceride levels may not be as bad as increased triglyceride levels caused by obesity or diabetes.
Predictions
Lipoprotein responses to estrogen therapy vary. There is some indication, however, that we may be able to predict which women will benefit from estrogen therapy. A 2001 study led by Jose J. Nieto and reported in the "Journal of the American College of Cardiology" indicated that women who had lower HDL cholesterol levels at baseline experienced a triglyceride increase, and were more susceptible to the adverse effects of estrogen therapy, than women whose baseline HDL level was higher. The study was small and may not be generalized to all women yet, but the theory is that low HDL cholesterol at baseline may be because of an abnormal metabolism of triglyceride-rich lipoproteins. The increase in VLDL production upon estrogen administration could be unmasking defects these women already have.
References
- The Jewish Hospital: Estrogen and Triglycerides
- "New England Journal of Medicine": Effects of Postmenopausal Estrogen Replacement
- "New England Journal of Medicine": Estrogen, Lipid Oxidation, and Body Fat
- "Journal of the American College of Cardiology": Estrogens, Lipids and Cardiovascular Disease: No Easy Answers
- "Obstetrics and Gynecology": Lipid Effects of Hormone Replacement Therapy With Sequential Transdermal 17-Beta-Estradiol and Oral Dydrogesterone
