Doctors at Harvard University claim women with high blood pressure face a greater likelihood of developing uterine fibroids. They published the results of a large study in the American Journal of Epidemiology this month.1
Familiar Malady
Fibroids are common among women of reproductive age. Estimates are that as many as 25 percent of women in the United States have symptoms that suggest they may have fibroids. These non-cancerous tumors grow within the uterine wall, and appear either as a single tumor or in clusters.
Symptoms include heavy bleeding or painful periods, bleeding between periods, a feeling of fullness in the lower abdomen, a need to urinate often, painful sex, lower back pain, and reproductive problems like infertility or recurrent miscarriages.2
Though fibroids aren't unusual, Rosalind Wright, MD, an assistant professor of Medicine at Harvard Medical School, and a team of researchers wrote that little is known about what factors underlie their development. But high blood pressure may be a culprit, they hypothesized. "Elevated diastolic blood pressure may increase fibroid risk though uterine smooth muscle injury, not unlike atherosclerosis," Wright and her colleagues wrote.
How did the researchers make that link? It's well known that people with high blood pressure are at increased risk of developing atherosclerosis, a disease characterized by hardening and narrowing of the arteries due to the formation of plaque.3 These lesions of plaque are made of fatty substances, cholesterol, cellular waste products and calcium, among other things.4 In high blood pressure, studies have suggested that abnormal changes occur in the smooth muscle cells that line the interior of arteries.3 Smooth muscle cells also make up the uterine wall.
Finding the Link
To confirm their theory, Wright's group prospectively studied the relationship of blood pressure and fibroids—known medically as uterine leiomyomata (lye-oh-my-oh-MAA-tuh)—in a group of 104,000 women already enrolled in the unrelated Nurses' Health Study II. None of the study participants had a history of cancer or fibroids when they were recruited, Wright and her colleagues wrote.
Each women was then followed for a total of 10 years. During that time, the researchers noted nearly 7,500 cases of uterine fibroids confirmed by ultrasound examination or hysterectomies.
Then, using statistical analysis and taking other potential factors that would affect the risk of developing fibroids into account, the research team found that for every 10-point increase in blood pressure, the risk of being diagnosed with fibroids jumped 8% in those not taking blood pressure medication, and 10% for those who were taking such medicines.
A New Treatment Strategy?
As a result of this finding, Wright and her team wrote that it may be necessary to explore newer ways to treat uterine fibroids. Further studies are needed, they stated, to determine whether controlling high blood pressure, or early detection and treatment for the condition, might reduce the risk of contracting fibroids or "complications associated with fibroids."
"Investigating this association may suggest possible pathways to prevent fibroids," they wrote.
Drawing Similar Conclusions
Other studies have suggested the same link. In a 2001 analysis,5 doctors in Finland pulled the records of 543 women who had undergone hysterectomy over a 10-year period. Information on the procedures they underwent, their use of hormone replacement therapy or other medication, previous pregnancy, weight, and blood pressure was also collected, as well as information on whether each woman had been diagnosed with uterine fibroids.
The research team learned that 42 percent of the women with hypertension had been diagnosed with fibroids compared to 37 percent of the women without hypertension. When analyzing the odds of contracting fibroids, women with high blood pressure had nearly twice the risk, they found. "The association between [fibroids] and hypertension was strongest among women with hysterectomies for benign adnexal tumors," the investigators noted. ("Adnexal" refers to areas outside the uterus, such as fallopian tubes, or ovaries).
1. Boynton-Jarrett R, Rich-Edwards J, Malspeis S, Missmer SA, Wright R. A prospective study of hypertension and risk of uterine leiomyomata. Am J Epidemiol 2005 Apr 1;161(7):628-38.
2. National Institute of Child Health & Human Development. National Institutes of Health (NIH). Fast Facts About Uterine Fibroids. Available at: http://www.nichd.nih.gov/publications/pubs/fibroids/sub1.htm#what. Accessed April 20, 2005.
3. Lembo G, Vecchione C, Morisco C et al. Arterial hypertension and atherosclerosis: their epidemiology and physiopathology. [Translated from Italian]. Ann Ital Med Int 1995 Oct;10 Supl:69S-72S.
4. American Heart Association. What is Atherosclerosis? Available at: http://www.americanheart.org/presenter.jhtml?identifier=4440. Accessed April 20, 2005.
5. Luoto R, Rutanen EM, Auvinen A. Fibroids and hypertension. A cross-sectional study of women undergoing hysterectomy. J Reprod Med 2001 Apr;46(4):359-64.
John Martin is a long-time health journalist and an editor for Priority Healthcare. His credits include coverage of health news for the website of Fox Television's The Health Network, and articles for the New York Post and other consumer and trade publications.
