Several months ago, I discovered a review article that looked at the current literature and analyzed the risk factors involved with uterine fibroid tumors. I often leave a link to this paper in my responses around this site and finally decided to do a little write-up of my own. Don’t be put off by the name. It’s just a fancy way to say “Uterine Fibroid Risk Factors”. For the truly geeky, there are a BUNCH of reference papers at the end of the review article. I’ll include a link to the web site and also the PDF file.
[Edited to add: One of my visitors was having problems accessing information from the original article so I uploaded the PDF file to my domain. If the PDF file listed above does not work for you, try here: Etiology and Pathogenesis of Uterine Leiomyomas: A Review (.pdf). Also, here’s a link to download the free Adobe Reader software to view PDF files.]
Uterine leiomyomas, or fibroids, are the most common tumors of women in the United States. The clinical effects of these tumors are related to their local mass effect, resulting in pressure upon adjacent organs, excessive uterine bleeding, or problems related to pregnancy, including infertility and repetitive pregnancy loss.
So, what are the causes or risk factors of uterine fibroid tumors?
The article discusses the risk factors of uterine fibroids in isolation but, keep in mind, there is often overlap or interaction. The size, number, and location will depend on a combination of a number of them. This table summarizes the results. (Click the thumbnail to view a larger image.)
There is a suggestion of slightly increased risk of fibroids associated with early menarche.
Starting menstruation at a young age increases your risk.
An increase with age in the prevalence of fibroids during the reproductive years especially a rapid increase in fibroid diagnoses among women in their forties.
Increased age (late reproductive years) increases your risk but…
this could be the result of increased growth of already existing fibroids.
Several studies have found an association between obesity and an increased incidence of uterine leiomyomas.
A higher weight or Body Mass Index increases your risk.
Uterine fibroids are more prevalent in black women than white women. In one study, 73% of black women and 48% of white women had uterine fibroids by ultrasound examination. In a study of premenopausal nurses in the United States, the incidence rates among these two groups [Asians and Hispanics], determined by ultrasound or hysterectomy, were similar to those of the white women.
African-American women are at increased risk.
Several clinical studies have now reported the growth or enlargement of uterine fibroids in breast cancer patients undergoing tamoxifen therapy.
Tamoxifen use increases your risk.
Several studies have shown an inverse relationship between parity and the risk of fibroids. A relative risk of fibroids among parous women of 0.5, compared with nulliparae, and a progressive decline in risk relative to the number of births have been reported.
Having no children (nullparity) increases your risk. Having more children decreases your risk.
A reduced risk of fibroids requiring surgery in postmenopausal patients…
…postmenopausal leiomyomas were smaller and fewer.
Menopause decreases your risk.
Several studies have revealed a reduced risk of fibroids associated with current smoking, but not past smoking. In one study, current smokers had a 50% reduced risk of uterine myomas requiring surgery.
Smoking decreases your risk.
Former nonathletes were found to be 1.4 times more likely than former athletes to develop benign uterine tumors.
Exercise decreases your risk.
…modulation of the diet can influence estrogen metabolism in premenopausal women, which may in turn influence the risk for fibroids.
The studies looked at low-fat/high-fiber diets and vegetarian vs. nonvegetarian diets. Results were not conclusive.
Consuming a low-fat/high-fiber diet may decrease your risk.
Reports suggest that uterine fibroids occur commonly in women in many parts of the world.
This inquisitive geek with fibroid tumors ™ blog has received hits from over 60 countries so I’m inclined to believe that.
Reports in the literature present inconsistencies with regard to the effect of oral contraceptive (OC) use upon the growth of myomas. These conflicting findings with regard to the effect of OCs upon the growth of myomas may relate to the differing content of estrogen and the type of progestogen in each specific OC preparation.
Use of oral contraceptives may increase your risk.
Hormone Replacement Therapy
Fibroids are expected to shrink after menopause, but hormone replacement therapy (HRT) may prevent this shrinkage and may even stimulate growth.
More studies with mixed results.
Use of HRT may increase your risk.
A diverse group of exogenous compounds, xenoestrogens, possesses the potential to disrupt normal estrogenic function as a result of either estrogenic agonist or antagonistic effects. No common chemical structure is predictive of estrogenic activity, and such substances may originate from dietary, industrial, or pharmaceutical sources.
Because there are so few studies, results are inconclusive.
Exposure to xenoestrogens (including organochlorine pesticides) may increase your risk.
For more information: (Thanks for the link fibroid free!)
Who gets fibroids?
What are uterine fibroid tumors?
Are uterine fibroid tumors a sign of cancer?
Psst… Where can I find pictures of fibroid tumors?
Would somebody tell me how much these dang fibroid tumors weigh?