Variation in the Incidence of Uterine Leiomyoma Among Premenopausal Women by Age and Race

TLDR

The study aimed to quantify the incidence of uterine leiomyoma confirmed by hysterectomy, ultrasound, or pelvic examination according to age and race among premenopausal women. It followed 95,061 premenopausal nurses aged 25‑44 from 1989 to 1993 and applied pooled logistic regression to estimate race‑specific relative risks of leiomyoma, adjusting for potential confounders. Over 327,065 woman‑years, 4,181 new leiomyoma cases were reported, incidence increased with age, and black women had a 3.25‑fold higher risk (RR = 3.25, 95 % CI 2.71–3.88) for ultrasound or hysterectomy‑confirmed diagnoses after adjustment, with higher risk factor prevalence not accounting for the excess.

Abstract

To quantify the incidence of uterine leiomyoma confirmed by hysterectomy, ultrasound, or pelvic examination according to age and race among premenopausal women.From September 1989 through May 1993, 95,061 premenopausal nurses age 25-44 with intact uteri and no history of uterine leiomyoma were followed to determine incidence rates of uterine leiomyoma. The self-reported diagnosis was confirmed in 93% of the medical records obtained for a sample of cases. Using pooled logistic regression, we estimated relative risks (RRs) of uterine leiomyoma according to race and examined whether adjustment for other potential risk factors could explain the variation in the race-specific rates.During 327,065 woman-years, 4181 new cases of uterine leiomyoma were reported. The incidence rates increased with age, and the age-standardized rates of ultrasound- or hysterectomy-confirmed diagnoses per 1000 woman-years were 8.9 among white women and 30.6 among black women. After further adjustment for marital status, body mass index, age at first birth, years since last birth, history of infertility, age at first oral contraceptive use, and current alcohol consumption, the rates among black women were significantly greater for diagnoses confirmed by ultrasound or hysterectomy (RR 3.25; 95% confidence interval [CI] 2.71, 3.88) and by hysterectomy (RR 1.82; 95% CI 1.17, 2.82) compared with rates among white women. We observed similar RRs when the cohort was restricted to participants who reported undergoing a screening physical examination within the 2 years before baseline.A higher prevalence of known risk factors did not explain the excess rate of uterine leiomyoma among premenopausal black women.