New directions in the epidemiology of uterine fibroids

Abstract

Although uterine leiomyomata (fibroids) have been the leading indication for hysterectomy in the United States for decades, the epidemiological data on fibroid prevalence and risk factors are limited. Given the hormonal dependence of fibroids, most earlier studies focused on reproductive or hormonal factors. Recent analyses have extended that focus to other areas. We present previously unpublished data on the association between reproductive tract infections and fibroids that highlight the need for more detailed studies. Our review suggests that metabolic, dietary, stress, and environmental factors may also play a role in fibroid development.

Figure 1

Age-specific cumulative incidence or prevalence estimates. The closed and open circles are prevalence data averaged over the age ranges shown for black and white women participating in Right From the Start, a community-based pregnancy study that screens for fibroids ≥5 mm in diameter at about 7-weeks gestation. The solid line and line of long dashes are cumulative incidence data from the NIEHS Uterine Fibroid Study, a study of 35-49 year old health plan members whose fibroid status was based on either ultrasound screening for fibroids ≥5 mm (premenopausal women) or on prior fibroid diagnosis (postmenopausal women). The line of short dashes is cumulative incidence data from the low-exposed group of potentially dioxin-exposed women (Seveso, Italy), 30-50 year olds whose fibroid status was based on either ultrasound screening for fibroids (premenopausal women) or on prior fibroid diagnosis (postmenopausal women). The squares are average cumulative incidence data for samples of 33-46 year old black and white participants in the CARDIA study, a population-based study of cardiovascular disease. The diamond is the average prevalence for fibroids for a group of 33-40 year old representative Swedish women who had ultrasound screening for fibroids of approximately 5 mm or greater in diameter.

Figure 2

The association between body mass index and fibroid development in the Black Women’s Health Study (BWHS), the NIEHS Uterine Fibroid Study (NIEHS), and the Nurses Health Study II after a 4-year followup (1998) and a 12-year followup (2007). The Nurses Health Study II participants are shown in the right column because the cohort is mostly white.