Higher uterine fibroid risk for Black women with maternal fibroid history

Key takeaways:

• Women with vs. without maternal fibroid history had a higher risk for uterine fibroids incidence.
• Uterine fibroid risk was strongest for women with mothers diagnosed at younger vs. older ages.

Black women whose mothers had uterine fibroids are at increased risk for the disease, especially if their mothers were diagnosed at younger ages, researchers reported in JAMA Network Open.

“Having a first-degree relative, primarily a mother or sister, with a history of uterine fibroids is thought to be a risk factor for fibroid development. Genetic associations with fibroids have been examined in familial aggregation, twin and genome-wide association studies; most, but not all, indicate that inherited genetic factors have some influence,” Christine R. Langton, PhD, special volunteer in the epidemiology branch at the National Institute of Environmental Health Sciences, and colleagues wrote. “However, social and environmental factors are also associated with fibroid risk and can be shared within families; thus, it is difficult to disentangle the contribution of shared environment vs. genetics among family members.”

Langton and colleagues conducted the Study of Environment, Lifestyle & Fibroids (SELF), a prospective community cohort study with data from 1,610 self-identified Black women from Detroit aged 23 to 35 years (mean age, 29.2 years) without uterine fibroids from 2010 to 2018. All participants were followed and underwent ultrasonographic exams at 20-month intervals over 5 years to detect uterine fibroids 0.5 cm or larger in diameter and to measure growth. Researchers obtained maternal uterine fibroid history from 88% of participants’ mothers and evaluated fibroid incidence with maternal fibroid history and age at maternal fibroid diagnosis.

In the incidence sample, 37% of participants had mothers diagnosed with uterine fibroids, of whom 24% were diagnosed from age 20 to 29 years. In the growth sample, 44% of participants had mothers diagnosed with uterine fibroids, of whom 27% were diagnosed from age 20 to 29 years, the researchers reported.

Overall, 24% of participants developed incident uterine fibroids.

Participants with maternal fibroid history had a higher uterine fibroids risk compared with those without maternal fibroid history (adjusted HR = 1.21; 95% CI, 0.96-1.52). Uterine fibroid risk was strongest among participants with mothers diagnosed at age 20 to 29 years (aHR = 1.56; 95% CI, 1.11-2.21) compared with diagnosis at age 30 to 39 years (aHR = 1.03; 95% CI, 0.71-1.49) and 40 years or older (aHR = 1.11; 95% CI, 0.81-1.52).

According to the researchers, fibroids followed for growth were generally small with a median volume of 2.2 cubic cm and a median growth of 69% per 18 per 18 months. Uterine fibroid growth rates were 8% higher by 8% among participants with maternal fibroid history compared with no fibroid history.

“Fibroids are an understudied condition, and there is still much to be elucidated concerning genetic and environmental factors and their interactions that influence development,” the researchers wrote. “Future genetic research may benefit from incorporation of data on the mother’s history of fibroids. Pregnancy cohorts that collect detailed data on mothers and offspring may also be an ideal source for future research.”

Editor’s note: This article was edited to more accurately reflect the size of uterine fibroids and their growth in this study.