Perceived racial discrimination and risk of uterine leiomyomata

Proceedings from the Third National Institutes of Health International Congress on Advances in Uterine Leiomyoma Research: comprehensive review, conference summary and future recommendations

BACKGROUND Uterine fibroids are the most common gynecologic tumors in women of reproductive age yet the etiology and pathogenesis of these lesions remain poorly understood. Age, African ancestry, nulliparity and obesity have been identified as predisposing factors for uterine fibroids. Symptomatic tumors can cause excessive uterine bleeding, bladder dysfunction and pelvic pain, as well as associated reproductive disorders such as infertility, miscarriage and other adverse pregnancy outcomes. Currently, there are limited noninvasive therapies for fibroids and no early intervention or prevention strategies are readily available. This review summarizes the advances in basic, applied and translational uterine fibroid research, in addition to current and proposed approaches to clinical management as presented at the 'Advances in Uterine Leiomyoma Research: 3rd NIH International Congress'. Congress recommendations and a review of the fibroid literature are also reported. METHODS This review is a report of meeting proceedings, the resulting recommendations and a literature review of the subject. RESULTS The research data presented highlights the complexity of uterine fibroids and the convergence of ethnicity, race, genetics, epigenetics and environmental factors, including lifestyle and possible socioeconomic parameters on disease manifestation. The data presented suggest it is likely that the majority of women with uterine fibroids will have normal pregnancy outcomes; however, additional research is warranted. As an alternative to surgery, an effective long-term medical treatment for uterine fibroids should reduce heavy uterine bleeding and fibroid/uterine volume without excessive side effects. This goal has not been achieved and current treatments reduce symptoms only temporarily; however, a multi-disciplined approach to understanding the molecular origins and pathogenesis of uterine fibroids, as presented in this report, makes our quest for identifying novel targets for noninvasive, possibly nonsystemic and effective long-term treatment very promising. CONCLUSIONS The Congress facilitated the exchange of scientific information among members of the uterine leiomyoma research and health-care communities. While advances in research have deepened our knowledge of the pathobiology of fibroids, their etiology still remains incompletely understood. Further needs exist for determination of risk factors and initiation of preventive measures for fibroids, in addition to continued development of new medical and minimally invasive options for treatment.

Lifetime abuse victimization and risk of uterine leiomyomata in black women

OBJECTIVE

Uterine leiomyomata (UL) are a major contributor to gynecologic morbidity and medical costs, and black women are disproportionately affected by the condition. Previous studies have linked UL to psychosocial stress, including child abuse. We assessed the association between lifetime abuse victimization and UL among 9910 premenopausal women.

STUDY DESIGN

Data were derived from the Black Women's Health Study, a prospective cohort study. In 2005, participants reported their experiences of physical and sexual abuse within each life stage (childhood, adolescence, adulthood). Biennial follow-up questionnaires from 2005 through 2011 ascertained new UL diagnoses. Rate ratios (RRs) and 95% confidence intervals (CIs) were estimated using Cox regression.

RESULTS

There were 1506 incident UL cases diagnosed by ultrasound or surgery. UL incidence was higher among women who reported child abuse, particularly sexual abuse. Relative to no abuse across the life span, RRs were 1.16 (95% CI, 1.02-1.33) for physical abuse only, 1.34 (95% CI, 1.09-1.66) for sexual abuse only, and 1.17 (95% CI, 0.99-1.39) for both physical and sexual abuse in childhood. RRs for 1-3 and 4 or more incidents of child sexual abuse were 1.29 (95% CI, 1.04-1.61) and 1.41 (95% CI, 1.07-1.85), respectively, whereas the RRs for low, intermediate, and high frequencies of child physical abuse were 1.19, 1.04, and 1.23, respectively. The association was strongest for the highest category of child abuse severity (RR, 1.57; 95% CI, 1.19-2.07). No associations were found for teen or adult abuse.

CONCLUSION

In the present study, child sexual abuse was an independent risk factor for UL, supporting the hypothesis that childhood adversity increases UL risk.

Are uterine leiomyoma a consequence of a chronically inflammatory immune system?

The cumulative incidence of uterine leiomyoma at age 50 is ≈ 70% in White women and >80% in Black women. Although risk factor research is limited, increasing age, and being premenopausal, nulliparous or Black are risk factors for leiomyomas. Black women tend to have larger leiomyomas and be younger at diagnosis. Surprisingly little is known about the etiology or pathogenesis of uterine leiomyomas. Women with diagnosed uterine leiomyomas have higher healthcare costs - more than 2.5 times that of women without a diagnosis. In the United States, leiomyomas are the leading indication for hysterectomy. The proposed hypothesis is that leiomyomas are caused in part by a systemic immune milieu that is chronically inflammatory - one that predominates in T helper 17 (Th17) cytokines. Inflammation can be problematic if it is not well regulated. Should an inflammatory imbalance be demonstrated to be associated with leiomyoma development and growth, this would provide an avenue for development of preventative treatments (e.g., focus on anti-inflammatory pathways), which would substantially reduce the morbidity costs of these tumors and reduce a known health disparity.

Early-life exposures and early-onset uterine leiomyomata in black women in the Sister Study

BACKGROUND

Uterine leiomyomata (fibroids) are hormonally responsive tumors, but little is known about risk factors. Early-life exposures may influence uterine development and subsequent response to hormones in adulthood. An earlier analysis of non-Hispanic white women who participated in the Sister Study found associations between several early-life factors and early-onset fibroids.

OBJECTIVES

We evaluated associations of early-life and childhood exposures with early-onset fibroids among black women and compared the results with those found among white women.

METHODS

We analyzed baseline data from 3,534 black women, 35-59 years of age, in the Sister Study (a nationwide cohort of women who had a sister diagnosed with breast cancer) who self-reported information on early-life and childhood exposures. Early-onset fibroids were assessed based on self-report of a physician diagnosis of fibroids by the age of 30 years (n = 561). We estimated risk ratios (RR) and 95% confidence intervals (CI) from log-binomial regression models.

RESULTS

Factors most strongly associated with early-onset fibroids were in utero diethylstilbestrol (DES; RR = 2.02; 95% CI: 1.28, 3.18), maternal prepregnancy diabetes or gestational diabetes (RR = 1.54; 95% CI: 0.95, 2.49), and monozygotic multiple birth (RR = 1.94; 95% CI: 1.26, 2.99). We also found positive associations with having been taller or thinner than peers at the age of 10 years and with early-life factors that included being the firstborn child of a teenage mother, maternal hypertensive disorder, preterm birth, and having been fed soy formula.

CONCLUSIONS

With the exception of monozygotic multiple birth and maternal hypertensive disorder, early-life risk factors for early-onset fibroids for black women were similar to those found for white women. However, in contrast to whites, childhood height and weight, but not low socioeconomic status indicators, were associated with early-onset fibroids in blacks. The general consistency of early-life findings for black and white women supports a possible role of early-life factors in fibroid development.

Self-Reported Daily Stress, Squelching of Anger and the Management of Daily Stress and the Prevalence of Uterine Leiomyomata: The Ultrasound Screening Study

Self-reported daily stress, ways of managing stress and squelching anger were examined in association with uterine leiomyomata (aka fibroids). These stress factors were obtained from 560 Black and 375 White women enrolled in the National Institute of Environmental Health Sciences Uterine Fibroid Study. Race-specific prevalence differences (PD) and 95% confidence intervals (95% CI) were calculated. Black women with severe stress had a prevalence of fibroids that was 11% higher (95% CI: 0%, 21%) than those in the no or mild stress group (referent). White women with severe stress, compared to the referent, had a non-significantly (NS) higher prevalence of fibroids [PD = 7%; 95% CI: (-103, 213)]. For both groups, moderate daily stress was associated with a weak elevation (NS) in fibroid prevalence. Black women who reported squelching their anger had an elevated prevalence of fibroids (8%) compared to non-squelchers [95% CI: (-03, 153)] while there was no association for White women. Women with symptomatic fibroids had higher stress than those without, but exclusion of symptomatic women only slightly attenuated the associations. Consistent with a previous report, symptomatic fibroids may cause stress. However, further research is warranted to prospectively investigate a possible aetiologic role for stress in the development of fibroids.

Racial discrimination, psychological distress, and self-rated health among US-born and foreign-born Black Americans

OBJECTIVES

We investigated associations among racial discrimination, psychological distress, and self-rated health among US-born and immigrant Black Americans.

METHODS

We conducted a cross-sectional analysis of a cohort of employed working-class Black Americans (193 US-born, 275 foreign-born).

RESULTS

Both US-born and foreign-born Black participants had high levels of exposure to poverty (51% and 57%, respectively) and racial discrimination (76% and 60%) and reported high levels of severe psychological distress (14% and 16% had a Kessler 6 [K6] score of 13 or greater); 17% and 7% reported fair or poor health. After controlling for relevant covariates, their risk parameters for racial discrimination (high vs no exposure) were 4.0 (95% confidence interval [CI] = 2.3, 5.6) and 3.3 (95% CI = 2.1, 4.5), respectively, for continuous K6 score; corresponding odds ratios for severe psychological distress were 6.9 (95% CI = 1.4, 35.7) and 6.8 (95% CI = 2.5, 18.3). No associations existed between racial discrimination and self-reported health, suggesting that an underlying propensity to report adversity does not account for our psychological distress findings.

CONCLUSIONS

Our results attest to the salience of racial discrimination, nativity, and socioeconomic position in understanding the experiences and psychological health of Black Americans.

Racial/ethnic residential segregation: framing the context of health risk and health disparities

An increasing body of public health literature links patterns of racial/ethnic residential segregation to health status and health disparities. Despite substantial new empirical work, meaningful understanding of the pathways through which segregation operates to influence health remains elusive. The literature on segregation and health was appraised with an emphasis on select conceptual, methodological, and analytical issues. Recommendations for advancing the next generation of racial/ethnic residential segregation and health research will require closer attention to sharpening the methodology of measuring segregation, testing mediating pathways and effect modification, incorporating stronger test of causality, exploring factors of resilience in segregated areas, applying a life-course perspective, broadening the scope of the investigation of segregation to include nativity status in blacks and other racial/ethnic groups, and linking segregation measures with biological data.

The association between self-reported major life events and the presence of uterine fibroids

PURPOSE

Uterine fibroids are the most common benign tumors in reproductive-age women. Factors associated with this condition such as psychosocial stress are still being elucidated. This paper explores the association between major life events (MLE) stress and fibroids.

METHODS

Prevalence ratios (PR) and 95% confidence intervals (CI) were used to determine the association between MLE stress (number of events and stress intensity) and fibroids in 556 Black and 373 White women in the Uterine Fibroid Study, 1996-1999.

MAIN FINDINGS

Fibroids were prevalent in 74% and 50% of the Black and White women, respectively. The mean number of MLE reported by each race group was two. Among White women, the PR for those who reported at least one event compared with those with no events were significant after adjusting for age and study identified fibroid risk factors (PR [1 and 2 events], 1.7; 95% CI, 1.2-2.5), (PR [3 events], 1.9; 95% CI, 1.3-2.7), and (PR [4 events], 1.5; 95% CI, 1.0-2.1), respectively. At all levels of stress compared with no events, significant associations with fibroids were found among White women. For Black women, the PR for fibroids was only significant in the high stress group compared with those without an experienced event, after adjusting for fibroid risk factors (PR, 1.2; 95% CI, 1.1-1.4).

CONCLUSION

Examining the number and stress intensity of MLE enriched our understanding of this stressor and fibroids. Further research is needed to understand the role of stress on fibroids among women.

New directions in the epidemiology of uterine fibroids

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.

Discrimination and racial disparities in health: evidence and needed research

This paper provides a review and critique of empirical research on perceived discrimination and health. The patterns of racial disparities in health suggest that there are multiple ways by which racism can affect health. Perceived discrimination is one such pathway and the paper reviews the published research on discrimination and health that appeared in PubMed between 2005 and 2007. This recent research continues to document an inverse association between discrimination and health. This pattern is now evident in a wider range of contexts and for a broader array of outcomes. Advancing our understanding of the relationship between perceived discrimination and health will require more attention to situating discrimination within the context of other health-relevant aspects of racism, measuring it comprehensively and accurately, assessing its stressful dimensions, and identifying the mechanisms that link discrimination to health.

Discrimination and racial disparities in health: evidence and needed research

This paper provides a review and critique of empirical research on perceived discrimination and health. The patterns of racial disparities in health suggest that there are multiple ways by which racism can affect health. Perceived discrimination is one such pathway and the paper reviews the published research on discrimination and health that appeared in PubMed between 2005 and 2007. This recent research continues to document an inverse association between discrimination and health. This pattern is now evident in a wider range of contexts and for a broader array of outcomes. Advancing our understanding of the relationship between perceived discrimination and health will require more attention to situating discrimination within the context of other health-relevant aspects of racism, measuring it comprehensively and accurately, assessing its stressful dimensions, and identifying the mechanisms that link discrimination to health.

Discrimination and racial disparities in health: evidence and needed research

This paper provides a review and critique of empirical research on perceived discrimination and health. The patterns of racial disparities in health suggest that there are multiple ways by which racism can affect health. Perceived discrimination is one such pathway and the paper reviews the published research on discrimination and health that appeared in PubMed between 2005 and 2007. This recent research continues to document an inverse association between discrimination and health. This pattern is now evident in a wider range of contexts and for a broader array of outcomes. Advancing our understanding of the relationship between perceived discrimination and health will require more attention to situating discrimination within the context of other health-relevant aspects of racism, measuring it comprehensively and accurately, assessing its stressful dimensions, and identifying the mechanisms that link discrimination to health.