Risk for uterine fibroids may be greater in women with high levels of testosterone and estrogen in midlife than women with low levels of both hormones, new data published in the Journal of Clinical Endocrinology and Metabolism suggest.
“Our research suggests women undergoing the menopausal transition who have higher testosterone levels have an increased risk of developing fibroids, particularly if they also have higher estrogen levels,” study author Jason Y.Y. Wong, ScD, of Stanford University School of Medicine in California, said in a press release. “This study is the first longitudinal investigation of the relationship between androgen and estrogen levels and the development of uterine fibroids.”
Though they are benign tumors, uterine fibroids can contribute to irregular bleeding, infertility, pelvic pain, recurrent pregnancy loss, and other reproductive complications, according to Dr Wong. First-line therapy includes hysterectomy, among several other treatment options.
While estrogen levels have already been implicated in the risk for uterine fibroids, in vitro studies indicate that testosterone may also play a role, Dr Wong and colleagues wrote in the study. However, the role of circulating androgen and its interplay with estrogen in the risk for uterine fibroids remain unclear.
For their analysis, the researchers conducted a 13-year longitudinal study of participants in the Study of Women’s Health Across the Nation (SWAN).
Of 3240 pre- or early perimenopausal women with an intact uterus aged 42 to 53 years enrolled at the beginning of the study, 43.6% completed follow-up.
During nearly annual visits, the researchers measured serum levels of bioavailable 17-beta estradiol and bioavailable testosterone and asked participants whether they had been diagnosed with or treated for uterine fibroids.
A total of 512 women reported having a single incidence of fibroids while an additional 478 women reported having recurrent fibroids.
Results showed that women with high testosterone levels vs low levels had a significantly higher risk for incident uterine fibroids (odds ratio [OR]=1.33; 95% CI, 1.01-1.76) but not recurrent fibroids. This risk was even higher for women with both high estrogen and high testosterone levels (OR=1.52; 95% CI, 1.07-2.17).
However, the risk for recurrent fibroids was lower in those with high levels of both hormones compared with those with low levels of the hormones (OR=0.50; 95% CI, 0.26-0.96).
“Our research suggests women undergoing the menopausal transition who have higher testosterone levels have an increased risk of developing fibroids, particularly if they also have higher estrogen levels,” noted Dr Wong. “This study is the first longitudinal investigation of the relationship between androgen and estrogen levels and the development of uterine fibroids.”
Another study author, Jennifer S. Lee, MD, PhD, of Stanford University School of Medicine and Veterans Affairs Palo Alto Health Care System, highlighted the potential ramifications of these data.
“Our findings are particularly interesting because testosterone was previously unrecognized as a factor in the development of uterine fibroids,” Dr Lee said in the release. “The research opens up new lines of inquiry regarding how fibroids develop and how they are treated. Given that managing uterine fibroids costs an estimated $34.4 billion in annual medical expenditures nationwide, it is important to identify new ways to better treat this common condition.”
Disclosure: The researchers report no relevant conflicts of interest.