Vitamin d and the risk of uterine fibroids.

BACKGROUND: Uterine leiomyomata (also known as fibroids) are benign tumors of uterine smooth muscle that are characterized by overproduction of extracellular matrix. Fibroids are the leading indication for hysterectomy in the United States. The active metabolite of vitamin D has been shown to inhibit cell proliferation and extracellular matrix production in fibroid tissue culture and to reduce fibroid volume in the Eker rat. No previous study has examined whether vitamin D is related to fibroid status in women. METHODS: The National Institute of Environmental Health Sciences Uterine Fibroid Study enrolled randomly selected 35- to 49-year-old women who were members of an urban health plan during 1996-1999. Fibroid status was determined by ultrasound screening of premenopausal women (620 blacks, 416 whites). Vitamin D status was assessed in stored plasma by radioimmunoassay of 25-hydroxyvitamin D (25(OH)D) and questionnaire data on sun exposure. Associations were evaluated with logistic regression, controlling for potential confounders. RESULTS: Only 10% of blacks and 50% of whites had levels of 25(OH)D regarded as sufficient (>20 ng/ml). Women with sufficient vitamin D had an estimated 32% lower odds of fibroids compared with those with vitamin D insufficiency (adjusted odds ratio [aOR] = 0.68, 95% confidence interval [CI] = 0.48-0.96). The association was similar for blacks and whites. Self-reported sun exposure ≥ 1 hour per day (weather permitting) was also associated with reduced odds of fibroids (aOR = 06. [0.4-0.9]), with no evidence of heterogeneity by ethnicity. CONCLUSIONS: The consistency of findings for questionnaire and biomarker data, the similar patterns seen in blacks and whites, and the biological plausibility provide evidence that sufficient vitamin D is associated with a reduced risk of uterine fibroids.

Growth of uterine leiomyomata among premenopausal black and white women.

Uterine leiomyomata (fibroids) are the leading cause of hysterectomy in the United States. Black women have a greater fibroid burden than whites, yet no study has systematically evaluated the growth of fibroids in blacks and whites. We prospectively tracked growth for 262 fibroids (size range: 1-13 cm in diameter) from 72 premenopausal participants (38 blacks and 34 whites). Fibroid volume was measured by computerized analysis of up to four MRI scans over 12 months. We used mixed effects models to identify factors that are associated with growth, and results were converted to percent change per 6 months for clinical relevance. The median growth rate was 9% (range: -89% to +138%). Seven percent of fibroids regressed (>20% shrinkage). Tumors from the same woman grew at different rates (within-woman component of variation was twice the component among women; both were significant, P < 0.001). Black and white women less than 35 years of age had similar fibroid growth rates. However, growth rates declined with age for whites but not for blacks (P = 0.05). The odds of a tumor growing more than 20% in 6 months also decreased with age for whites but not for blacks (P < 0.01). Growth rates were not influenced by tumor size, location, body mass index, or parity. We conclude that (i) spontaneous regression of fibroids occurs; (ii) fibroids from the same woman grow at different rates, despite a uniform hormonal milieu; (iii) fibroid size does not predict growth rate; and (iv) age-related differences in fibroid growth between blacks and whites may contribute to the higher symptom burden for black women.

Within-person variability in urinary bisphenol A concentrations: measurements from specimens after long-term frozen storage.

BACKGROUND: Bisphenol A (BPA) is an estrogenic contaminant of food and water associated with adverse developmental effects in laboratory animals. BPA has recently been linked to morbidity in adult humans, but studies of developmental effects in humans are methodologically more difficult. The ability to measure BPA in urine samples after long-term storage could aid in such studies. Because the half-life of BPA is < 6h, a single measurement would be useful only if the environmental exposure is relatively constant over weeks or months. Our aims were to evaluate the stability of BPA in specimens after 22-24 years of storage and to measure within-person temporal variability in urinary BPA. METHODS: We measured total BPA concentration by mass spectrometry in first-morning urine samples from 60 premenopausal women. We selected from each woman's stored daily collections three urine samples approximately 2 and 4 weeks apart. Samples were selected from both the follicular and luteal phases of the menstrual cycle to assess cycle effects. Temporal variability was assessed with mixed model regression and correlations. RESULTS: BPA levels had an inter-quartile range from 1.1 to 3.1 ng/mg creatinine, slightly higher than levels in specimens from NHANES collected 3-11 years later. The Spearman correlation was approximately 0.5 for samples 2 weeks apart and 0.3 for samples 4 weeks apart. Menstrual cycle phase did not influence levels. BPA tended to increase during the three-year collection period, but not significantly. CONCLUSIONS: The similar distribution to NHANES samples and correlation of BPA levels taken at 2-week intervals provide indirect evidence that BPA is relatively stable during long-term freezer storage. The correlations indicate generally stable exposures over periods of weeks. These findings suggest that developmental effects of BPA exposure could be investigated with measurements from stored urine.

The gestational timing of pregnancy loss: adaptive strategy?

This commentary links early pregnancy milestones (rescue of the corpus luteum, the luteal-placental shift, and blocking of the spiral arteries) with the pattern of gestation-specific pregnancy loss in humans. The objective is to describe the pattern and present an adaptive hypothesis: that high first trimester pregnancy loss results from selection to reduce the risk of maternal morbidity and mortality associated with human delivery. Specific questions within the broad framework of this hypothesis can be addressed with research in comparative physiology and endocrinology.

Associations of abdominal fat with perceived racism and passive emotional responses to racism in African American women.

OBJECTIVES: An excess in abdominal fat may predispose African American women to chronic health conditions such as diabetes and cardiovascular disease. Because stress may increase body fat in the center-body region, we used the waist-to-hip ratio (WHR) to examine associations between excess abdominal fat and perceived racism (a chronic stressor) and daily stress. Passive emotional responses to perceived racism, hypothesized to have particularly adverse effects, were also examined. METHODS: We controlled for body mass index in multiple logistic regression models among 447 African American women who completed a telephone interview on perceived racism. RESULTS: Passive emotional responses were not related to WHR (odds ratio [OR]=1.4; 95% confidence interval [CI]=0.8, 2.4). High perceived racism was associated with a low WHR in this population (OR=0.4; 95% CI=0.3, 0.8). However, high daily stress was related to a high WHR (OR=2.7; 95% CI=1.1, 6.7). CONCLUSIONS: Findings support an association between daily stress and WHR but do not support our hypothesis that passive emotional responses to perceived racism increase abdominal fat. Further study of the stress physiology of perceived racism in African American women is warranted.

A comparison of recalled date of last menstrual period with prospectively recorded dates.

BACKGROUND: Women are often asked to recall the first day of their last menstrual period (LMP date) in a clinic setting (i.e., pregnancy dating, x-rays). There are no data supporting the validity of these reports. METHODS: Using data from a group of 385 women ages 35-49 from a larger cohort study in the Washington, DC, area, we constructed menstrual segments from a prospective daily menstrual record. We then compared the first day of a menstrual segment to a woman's recalled LMP date at a subsequent study-related clinic appointment to assess the accuracy of recall. RESULTS: More than half of the women (56%) accurately recalled their LMP date; 74% were within 1 day, and 81% were within 2 days. Women tended to underreport (25%) the length of time since their last menstrual period rather than overreport the length of time (19%). Recall accuracy did not vary significantly with education or by whether the woman usually recorded her menstrual cycle when not in the study. As one might expect, women with a shorter recall duration tended to report more accurately. DISCUSSION: Women appear to recall their LMP dates fairly accurately, but inaccurate recall was not random. When length of recall was 3 weeks or longer, women tended to overestimate the time since LMP. This suggests that gestational age calculated from LMP date will tend to be overestimated. Most women can recall the date of their LMP reasonably well regardless of their education and whether they usually record their LMP dates.

Prenatal diethylstilbestrol (DES) exposure is associated with uterine leiomyoma development.

Early life exposure to DES causes uterine leiomyomata in laboratory animals. We examined the relationship between prenatal DES exposure and development of uterine leiomyomata in women. Among randomly selected study participants (819 black women, 504 white women), leiomyoma status was determined by ultrasound screening (70%) or surgical record review (7%). We relied on self-report of prior diagnosis in 13%. Leiomyoma status could not be ascertained for 10% and they were excluded from analyses. Prenatal DES exposure was assessed by interview. All five of the black women who reported DES exposure had leiomyomata. Among white women, 76% who reported prenatal DES exposure had leiomyomata compared with 52% of the unexposed (adjusted odds ratio for whites: 2.4; 95% confidence interval CI: 1.1-5.4). Exposed women tended to have larger tumors. Results were robust to sensitivity analyses. Findings support experimental animal data and indicate a role for prenatal estrogen exposure in the etiology of human uterine leiomyoma.

Self-reported heavy bleeding associated with uterine leiomyomata.

OBJECTIVE: To characterize the relationship between self-reported bleeding symptoms and uterine leiomyoma size and location. METHODS: The leiomyoma status of a randomly selected sample of women aged 35-49 in the Washington, DC, area was determined using abdominal and transvaginal ultrasound to measure size and location of leiomyomata found at screening. Women were asked about symptoms of heavy bleeding (gushing-type bleeding, long menses, pad/tampon use) in a telephone interview. Using multivariable regression, we examined the relationships between leiomyoma characteristics and heavy bleeding symptoms among 910 premenopausal women. RESULTS: Women with leiomyomata (n = 596) were more likely to report gushing-type bleeding than women without leiomyomata; risk increased with leiomyoma size. Adjusted relative risks with 95% confidence intervals (CI) for women in each leiomyoma size category compared with the reference category (women without leiomyomata) were as follows: adjusted relative risk of 1.4 (95% CI 1.1, 1.9) for diffuse only, adjusted relative risk of 1.4 (95% CI 1.1, 1.8) for small leiomyomata (less than 2 cm), adjusted relative risk of 1.6 (95% CI 1.3, 2.0) for medium leiomyomata (2-5 cm), and adjusted relative risk of 1.9 (95% CI 1.5, 2.5) for large leiomyomata (greater than 5 cm). Reported use of eight or more pads/tampons on the heaviest days of menstrual bleeding increased with leiomyoma size, with a nearly 2.5-fold risk for women with large leiomyomata compared with women without leiomyomata (adjusted relative risk of 2.4; 95% CI 1.8, 3.1). Nonsubmucosal leiomyomata were associated with essentially the same increase in heavy bleeding as submuscosal leiomyomata of similar size. CONCLUSION: Small leiomyomata were associated with increased risk of heavy bleeding, and risk increased with size. Contrary to published articles, nonsubmucosal leiomyomata were associated with heavy bleeding to the same extent as submucosal leiomyomata.

Self-reported family history of leiomyoma: not a reliable marker of high risk.

PURPOSE: To examine the importance of self-reported family history of uterine leiomyoma (fibroids) as a marker of risk. METHODS: Women, aged 35 to 49, were randomly selected from the membership of a large, urban health plan. Participants completed a self-administered questionnaire about family history of fibroids. Ultrasound screening for fibroids followed, regardless of whether participants had been previously diagnosed (660 black, 412 white). Data for each ethnic group were analyzed separately using Poisson regression. RESULTS: In both ethnic groups, women who reported a family history of fibroids had an elevated risk of fibroids compared with those without family history. However, no elevated risk was apparent for cases who did not know they had fibroids when they reported the family history information. CONCLUSIONS: Many women may first learn about their family history of fibroids when discussing their own clinical diagnosis with family members. Such bias would invalidate self-reported family history as a predictor of fibroid risk. As new pharmacologic treatments for fibroids are developed, women at high risk of fibroids would benefit from early screening and pharmacologic treatment to delay development of large fibroids and reduce the need for invasive treatments. Self-reported family history is not useful for identifying high-risk women.

Cytokine patterns differ seasonally between women with and without uterine leiomyomata.

PROBLEM: Uterine leiomyomata are the most common reproductive tumor in women, and their cause is not known. METHODS OF STUDY: Plasma samples from 155 women (74 with and 81 without ultrasound-confirmed leiomyoma) from a new study of leiomyoma risk factors in the Detroit, Michigan area, were examined for any cross-sectional associations between commonly examined cytokines and leiomyoma presence. RESULTS: Associations varied by season of sample collection defined a priori as winter (December-February) and non-winter seasons. In the winter months, interleukin (IL)13 and IL17 were positively and IP10 was inversely associated with having a leiomyoma. In the non-winter samples, VEGF, G-CSF, and IP10 were positively associated and Monocyte chemotactic protein-1, IL13, and IL17 were inversely associated with having a leiomyoma. Associations were not changed by adjustment for age or BMI. CONCLUSIONS: These data suggest that new insight into leiomyoma formation may be acquired through investigation of the immune system.

Gene expression in uterine leiomyoma from tumors likely to be growing (from black women over 35) and tumors likely to be non-growing (from white women over 35).

The study of uterine leiomyomata (fibroids) provides a unique opportunity to investigate the physiological and molecular determinants of hormone dependent tumor growth and spontaneous tumor regression. We conducted a longitudinal clinical study of premenopausal women with leiomyoma that showed significantly different growth rates between white and black women depending on their age. Growth rates for leiomyoma were on average much higher from older black women than for older white women, and we now report gene expression pattern differences in tumors from these two groups of study participants. Total RNA from 52 leiomyoma and 8 myometrial samples were analyzed using Affymetrix Gene Chip expression arrays. Gene expression data was first compared between all leiomyoma and normal myometrium and then between leiomyoma from older black women (age 35 or older) and from older white women. Genes that were found significant in pairwise comparisons were further analyzed for canonical pathways, networks and biological functions using the Ingenuity Pathway Analysis (IPA) software. Whereas our comparison of leiomyoma to myometrium produced a very large list of genes highly similar to numerous previous studies, distinct sets of genes and signaling pathways were identified in comparisons of older black and white women whose tumors were likely to be growing and non-growing, respectively. Key among these were genes associated with regulation of apoptosis. To our knowledge, this is the first study to compare two groups of tumors that are likely to have different growth rates in order to reveal molecular signals likely to be influential in tumor growth.

Self-report versus ultrasound measurement of uterine fibroid status.

BACKGROUND: Much of the epidemiologic research on risk factors for fibroids, the leading indication for hysterectomy, relies on self-reported outcome. Self-report is subject to misclassification because many women with fibroids are undiagnosed. The purpose of this analysis was to quantify the extent of misclassification and identify associated factors. METHODS: Self-reported fibroid status was compared to ultrasound screening from 2046 women in Right From The Start (RFTS) and 869 women in the Uterine Fibroid Study (UFS). Log-binomial regression was used to estimate sensitivity (Se) and specificity (Sp) and examine differences by ethnicity, age, education, body mass index, parity, and miscarriage history. RESULTS: Overall sensitivity was ≤0.50. Sensitivity was higher in blacks than whites (RFTS: 0.34 vs. 0.23; UFS: 0.58 vs. 0.32) and increased with age. Parous women had higher sensitivity than nulliparae, especially in RFTS whites (Se ratio=2.90; 95% confidence interval [CI]: 1.51, 5.60). Specificity was 0.98 in RFTS and 0.86 in UFS. Modest ethnic differences were seen in UFS (Sp ratio, black vs. white=0.90; 95% CI: 0.81, 0.99). Parity was inversely associated with specificity, especially among UFS black women (Sp ratio=0.84; 95% CI: 0.73, 0.97). Among women who reported a previous diagnosis, a shorter time interval between diagnosis and ultrasound was associated with increased agreement between the two measures. CONCLUSIONS: Misclassification of fibroid status can differ by factors of etiologic interest. These findings are useful for assessing (and correcting) bias in studies using self-reported clinical diagnosis as the outcome measure.

Short-term change in growth of uterine leiomyoma: tumor growth spurts.

OBJECTIVE: To describe the short-term changes in growth of uterine leiomyomas (fibroids). DESIGN: Prospective observational study. SETTING: University research center. PATIENT(S): Premenopausal women with fibroids (18 blacks and 18 whites) recruited through a physician network and community outreach. INTERVENTION(S): Not applicable. MAIN OUTCOME MEASURE(S): The volumes of 101 fibroids were measured at enrollment, 3, 6, and 12 months with magnetic resonance imaging, resulting in three interval-specific growth rates. Growth spurts were defined by interval growth rates≥30% per 3 months and substantially greater than during other intervals of observation. An overall measure of short-term change in fibroid growth was calculated as the variance of the three interval-specific growth rates. RESULT(S): Growth spurts were observed in 37 of the 101 fibroids, a prevalence nearly tenfold higher than that attributable to potential measurement error. Fibroids from the same woman did not have similar short-term growth, nor were woman-specific factors (age, race/ethnicity, parity, body mass) or the fibroid position in the uterus important. However, large fibroids (>5 cm diameter) had less short-term change than smaller fibroids. CONCLUSION(S): Short spurts of growth are common for fibroids, suggesting that tumor biology may change rapidly.

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.

Within-person variability in urinary phthalate metabolite concentrations: measurements from specimens after long-term frozen storage.

Laboratory studies show that exposure to phthalates during development can cause adverse effects, especially for males. Studies in humans would be facilitated by collection of urine during pregnancy, long-term storage, and measurement of phthalate metabolites at the time that offspring health is assessed. Our aims were to measure urinary phthalate metabolites after long-term freezer storage, to use those measurements to evaluate within-woman variability over 2- and 4-week intervals, and to determine whether the phases of the menstrual cycle affect metabolite levels. Samples were selected from daily first-morning urine specimens collected by 60 women and stored frozen since 1983-1985. Three specimens per woman were selected at approximately 2-week intervals to include both follicular and luteal phase samples. Seven metabolites of five phthalates were measured by mass spectrometry. Statistical analyses were conducted with correlation, mixed model regression, and the Wilcoxon signed rank test. Creatinine-corrected urinary phthalate metabolite concentrations measured in samples after long-term storage tended to have a similar right-skewed distribution, though with somewhat higher concentrations than those reported for recently collected US samples. The concentrations of three metabolites of di(2-ethylhexyl)phthalate in the same specimen were very highly correlated (Pearson r=0.85-0.97). Reproducibility over a 4-week interval was moderate for the metabolites of diethyl phthalate and benzylbutyl phthalate (intraclass correlation coefficients, ICCs, 0.48 and 0.53, respectively), whereas five other metabolites had lower ICCs (0.21-0.37). Menstrual phase was not related to metabolite concentrations. Although the same samples have not been measured both before and after long-term storage, results suggest that the measurement of phthalate metabolites after long-term sample storage yield generally similar distributions and temporal reliability as those reported for recently collected specimens. These findings support the use of stored urine specimens collected during the relevant stage of human pregnancy to investigate the influence of phthalate exposures on later outcomes.

The fibroid growth study: determinants of therapeutic intervention.

AIMS: The demographics, ethnicity, symptoms, lifestyle characteristics, and treatment outcomes are analyzed in participants of a study designed to evaluate uterine leiomyoma growth and correlate symptoms and outcomes in a clinically relevant population of women (Fibroid Growth Study). METHODS: Women included in the Fibroid Growth Study (FGS) completed a medical history and physical examination, underwent T1-weighted and T2-weighted magnetic resonance image (MRI) scans, provided urine and blood samples at each scheduled MRI, and responded to an initial extensive telephone-administered questionnaire followed by abbreviated monthly questionnaire updates. Summary scores were developed to quantify stress, pain, and bleeding. The Wilcoxin test was used for statistical comparisons between study participant characteristics and tumor-related characteristics. RESULTS: Participants included 116 premenopausal women, ranging in age from 20 to 54 years; 48% were black women, 41% were white women, 10% were women of other or multiple racial backgrounds, and 1% did not self-identify. Over 90% of participants had multiple leiomyomas, and nearly a third had more than 10. Black women were younger and had more fibroids, but no differences were found in the proportions of black and white women choosing an intervention; 44% of black women and 40% of white women chose intervention during the study. CONCLUSIONS: There was no correlation between number of leiomyomas or uterine size and choosing treatment. However, women who opted for treatment were more symptomatic, with higher bleeding and pain scores, compared with the women with no intervention. Consequently, our study suggests that once women are symptomatic, black and white women choose surgery as a treatment method for the same reasons and at about the same rates. Moreover, our data suggest that bleeding and pain, not the size or multiplicity of fibroids, determine the choice for intervention. Therefore, aggressive management of pain and bleeding may be effective in reducing the need for surgical intervention.

Association of physical activity with development of uterine leiomyoma.

The relation between physical activity and uterine leiomyomata (fibroids) has received little study, but exercise is protective for breast cancer, another hormonally mediated tumor. Participants in this study were randomly selected members of a health plan based in Washington, DC, aged 35-49 years (734 African Americans, 455 Whites) enrolled between 1996 and 1999. Fibroid status was based on ultrasound screening. Physical activity was based on detailed interview questions. Logistic regression with adjustment for body mass index and other risk factors showed that women in the highest category of physical activity were significantly less likely to have fibroids (odds ratio = 0.6, 95% confidence interval = 0.4, 0.9 for the highest vs. the lowest category (equivalent to approximately > or =7 hours/week vs <2 hours/week)). There was a dose-response pattern; a significant trend was seen for both African-American and White women. A multistate Bayesian analysis indicated that exercise was associated with tumor onset more strongly than with tumor growth. When data for women who reported major fibroid-related symptoms were excluded, results remained essentially unchanged, suggesting that the observed association could not be attributed to reverse causation (fibroids preventing exercise). The authors concluded that regular exercise might help women prevent fibroids.