Jodi A. Flaws

Smoking, body mass, and hot flashes in midlife women☆

OBJECTIVE To assess whether lifestyle factors, specifically smoking and body mass index (BMI), are associated with the occurrence of any, moderate to severe, or daily hot flashes. METHODS A cross-sectional study was conducted among women aged 40–60 years residing in the Baltimore metropolitan area who reported their history of hot flashes through a mailed survey. Logistic regression was used to assess the associations between smoking and BMI with any, moderate to severe, and daily hot flashes. RESULTS Of the 1087 women included in the study, 56% reported having hot flashes. Compared with never-smokers, current smokers were at an increased risk for both moderate to severe hot flashes (adjusted odds ratio [OR] = 1.9, 95% confidence interval [CI] 1.3, 2.9) and daily hot flashes (adjusted OR = 2.2, 95% CI 1.4, 3.7). Among current smokers, risk for hot flashes increased with greater amount smoked. High BMI (more than 30 kg/m2) was associated with an increased risk for moderate to severe hot flashes compared with low BMI (less than 24.9 kg/m2) (adjusted OR = 2.1, 95% CI 1.5, 3.0). An increased risk for any or daily hot flashes with high BMI was present only among premenopausal or perimenopausal women. CONCLUSION Potentially modifiable factors, such as current smoking and high BMI, may predispose a woman to more severe or frequent hot flashes. This information may be valuable for identifying women at risk for hot flashes and for developing appropriate prevention strategies that may include lifestyle modifications.

Effect of Bcl-2 on the Primordial Follicle Endowment in the Mouse Ovary

Abstract Little is known about the embryonic factors that regulate the size of the primordial follicle endowment at birth. A few studies suggest that members of the B-cell lymphoma/leukemia-2 (bcl-2) family of protooncogenes may be important determinants. Thus, the purpose of this study was to test whether bcl-2 regulates the size of the primordial follicle pool at birth. To test this hypothesis, three lines of transgenic mice (c-kit/bcl-2 mice) were generated that overexpress human bcl-2 in an effort to reduce prenatal oocyte loss. The overexpression was targeted to the ovary and appropriate embryonic time period with the use of a 4.8-kilobase c-kit promoter. This promoter provided two to three times more expression of bcl-2 in the ovaries with minimal or no overexpression in most nongonadal tissues. On Postnatal Days 8–60, ovaries were collected from homozygous c-kit/bcl-2 and nontransgenic littermates (controls) and processed for histological evaluation of follicle numbers. All lines of c-kit/bcl-2 mice were born with significantly more primordial follicles than control mice (P ≤ 0.05). By Postnatal Days 30–60, however, there were no significant differences in follicle numbers between c-kit/bcl-2 and control mice. These results indicate that bcl-2 overexpression increases the number of primordial follicles at birth, but that the surfeit of primordial follicles is not maintained in postnatal life. These data suggest that it is possible that the ovary may contain a census mechanism by which excess numbers of primordial follicles at birth are detected and removed from the ovary by adulthood.

BRCA2 deficiency in mice leads to meiotic impairment and infertility

The role of Brca2 in gametogenesis has been obscure because of embryonic lethality of the knockout mice. We generated Brca2-null mice carrying a human BAC with the BRCA2 gene. This construct rescues embryonic lethality and the mice develop normally. However, there is poor expression of the transgene in the gonads and the mice are infertile, allowing examination of the function of BRCA2 in gametogenesis. BRCA2-deficient spermatocytes fail to progress beyond the early prophase I stage of meiosis. Observations on localization of recombination-related and spermatogenic-related proteins suggest that the spermatocytes undergo early steps of recombination (DNA double strand break formation), but fail to complete recombination or initiate spermiogenic development. In contrast to the early meiotic prophase arrest of spermatocytes, some mutant oocytes can progress through meiotic prophase I, albeit with a high frequency of nuclear abnormalities, and can be fertilized and produce embryos. Nonetheless, there is marked depletion of germ cells in adult females. These studies provide evidence for key roles of the BRCA2 protein in mammalian gametogenesis and meiotic success.

Body mass and stage of breast cancer at diagnosis

Obesity is a well‐known risk factor for postmenopausal breast cancer. In contrast, the relationship between obesity and stage of breast cancer at diagnosis is less clear. We hypothesized that increased breast size in obese women may delay discovery of breast tumors. Thus, the purpose of our study was to examine whether there is an association between body mass and stage of breast cancer at diagnosis using hospital medical records. Newly diagnosed breast cancer cases (n = 966) in the Baltimore metropolitan area from 1991 to 1997 were included in our study. Patient information including age, ethnicity, weight, height and pathology data were obtained from hospital medical records. High body mass was significantly associated with late stage of breast cancer at diagnosis. Women who were obese (body mass index [BMI] ≥ 27.3) were more likely to be at an advanced stage at diagnosis compared with women with a BMI of < 27.3 (multivariate‐adjusted odds ratio [OR] 1.57, 95% confidence interval [CI] 1.15–2.14). The association between body mass and stage at diagnosis was stronger among women younger than 50 years (OR 2.34, 95% CI 1.34–4.08) compared with women 50 years or older (OR 1.30, 95% CI 0.89–1.91). Our study suggests that higher body mass is associated with advanced stage of breast cancer at diagnosis. This finding may be of considerable concern, given the increasing prevalence of obesity in women in the United States and the poor prognosis associated with late‐stage tumors.

Hormone replacement therapy and breast cancer: a qualitative review.

OBJECTIVE To assess whether recent epidemiologic evidence supports an association between use of estrogen replacement therapy or hormone replacement therapy and risk of breast cancer. DATA SOURCES The keywords “estrogen,” “estrogen replacement therapy,” or “hormone replacement therapy,” and “breast cancer” or “breast neoplasm,” were used to search for articles published from 1975–2000 in MEDLINE and Dialogweb. Only articles published in peer‐reviewed journals and containing original data were included in this review. METHODS Unadjusted or age‐adjusted risk estimates for breast cancer among ever users of estrogen therapy compared with never users were abstracted from published articles or calculated using the data provided in the published reports. TABULATION, INTEGRATION, AND RESULTS We found little consistency among studies that estimated the risk of breast cancer in hormone users compared with nonusers and in studies assessing the risk by duration of use. However, there was consistently a lower risk of death from breast cancer in hormone users compared with nonusers. CONCLUSION The evidence did not support the hypotheses that estrogen use increases the risk of breast cancer and that combined hormone therapy increases the risk more than estrogen only. Additional observational studies are unlikely to alter this conclusion. Although a small increase in breast cancer risk with hormone therapy or an increased risk with long duration of use (15 years or more) cannot be ruled out, the likelihood of this must be small, given the large number of studies conducted to date.

Destruction of preantral follicles in adult rats by 4-vinyl-1-cyclohexene diepoxide

4-vinyl-1-cyclohexene diepoxide (VCD) is known to destroy oocytes in ovaries of immature rats. Since ovaries functionally differ between immature and adult animals, we examined the effect of VCD on oocytes in adult rats. Adult (58 days) and immature (28 days) rats were injected daily (30 days) with vehicle or VCD. Each group contained 10 rats. During this time, cyclicity was determined daily by vaginal cytology. Animals were terminated on day 31 and tissues were collected. Oocytes were counted; livers, spleens, and uteri were weighed. VCD reduced the number of regular estrous cycles/30 days in adults, but not immature rats (n = 20, P < 0.05). VCD reduced the number of oocytes in adult and immature rats (n = 20, P < 0.05). Liver, spleen, or ovarian weights were not affected by VCD in either group. VCD reduced uterine weight in adult (n = 20, P < 0.05) but not in immature rats. These results demonstrate that VCD decreases uterine weight in adult rats and as with immature rats, selectively destroys oocytes in ovaries of adults.

Risk factors for hot flashes in midlife women

OBJECTIVEnTo review the scientific literature pertaining to potential risk factors for hot flashes in midlife women.nnnMETHODSnScientific publications reporting on risk factors for hot flashes were identified through a systematic Medline search and are summarized in this review paper.nnnRESULTSnAlthough few studies have investigated risk factors for hot flashes in midlife women, consistent evidence suggests that smoking is associated with an increased risk for hot flashes. In addition, some studies suggest that other factors, such as hormone levels, body size, tubal ligation, surgical menopause, and race/ethnicity, may be associated with the occurrence of hot flashes.nnnCONCLUSIONSnFuture studies are needed to confirm previous findings and to identify additional risk factors for hot flashes. Such studies will increase our understanding of the etiology of hot flashes and may lead to better treatments and preventive measures for this condition.

The correlations between estradiol, estrone, estriol, progesterone, and sex hormone-binding globulin and anterior cruciate ligament stiffness in healthy, active females.

BACKGROUNDnInjury to the anterior cruciate ligament (ACL) often requires surgery and extensive rehabilitation. Women who participate in collegiate sports and military drills are more likely to injure their ACL than are men participating in similar activities. The influence of the normal fluctuation of sex hormones on the physical properties of the ACL is one potential cause for this disparity. The purpose of this study was to report the correlation between estradiol, estrone, estriol, progesterone, and sex hormone binding globulin (SHBG) and ACL stiffness during three phases of the menstrual cycle in normally cycling, healthy females.nnnMETHODSnWe tested ACL stiffness and collected blood from 20 female subjects who were not using oral contraception during three phases of their menstrual cycle. Ligament stiffness was tested with the KT-2000 trade mark knee arthrometer (MEDmetric, San Diego, CA). Concentrations of estradiol and SHBG were assessed via radioimmunoassay (RIA). Progesterone, estriol, and estrone concentrations were determined via enzyme-linked immunoassay.nnnRESULTSnSpearman rank correlation analysis indicated a significant correlation between estradiol concentration and ACL stiffness (-0.70, p < 0.001) and estrone concentration and ACL stiffness near ovulation (0.46, p = 0.040). With the effects of the other variables controlled, there was a significant partial correlation between estradiol (-0.80, p < 0.001), estriol (0.70, p = 0.003), and progesterone (0.66, p = 0.005) and ACL stiffness near ovulation.nnnCONCLUSIONSnOur results indicate that there is a significant correlation between estradiol, estriol, and progesterone and ACL stiffness suggesting that fluctuating levels of sex hormones may influence the stiffness of the ACL near ovulation. Future studies that examine the relationship between sex hormones and the physical properties of the ACL should be focused near the ovulation phase of the menstrual cycle.

Smad 3 May Regulate Follicular Growth in the Mouse Ovary

Abstract Although Smad 3 is known to serve as a signaling intermediate for the transforming growth factor beta (TGFβ) family in nonreproductive tissues, its role in the ovary is unknown. Thus, we used a recently generated Smad 3-deficient (Smad 3−/−) mouse model to test the hypothesis that Smad 3 alters female fertility and regulates the growth of ovarian follicles from the primordial stage to the antral stage. In addition, we tested whether Smad 3 affects the levels of proteins that control apoptosis, survival, and proliferation in the ovarian follicle. To test this hypothesis, breeding studies were conducted using Smad 3−/− and wild-type mice. In addition, ovaries were collected from Smad 3−/− and wild-type mice on Postnatal Days 2–90. One ovary from each animal was used to estimate the total number of primordial, primary, and antral follicles. The other ovary was used for immunohistochemical analysis of selected members of the B-cell lymphoma/leukemia-2 family of protooncogenes (Bax, Bcl-2, Bcl-x), proliferating cell nuclear antigen (PCNA), and cyclin-dependent kinase 2 (Cdk-2). The results indicate that Smad 3−/− mice have reduced fertility compared with wild type mice. The results also indicate that Smad 3 may not affect the size of the primordial follicle pool at birth, but it may regulate growth of primordial follicles to the antral stage. Further, the results indicate that Smad 3 may regulate the expression of Bax and Bcl-2, but not Bcl-x, Cdk-2, and PCNA. Collectively, these data suggest that Smad 3 may play an important role in the regulation of ovarian follicle growth and female fertility.

Aryl Hydrocarbon Receptor Regulates Growth, But Not Atresia, of Mouse Preantral and Antral Follicles

Abstract The aryl hydrocarbon receptor (AhR) is a ligand-activated transcription factor that binds various environmental contaminants. Despite our knowledge regarding the role of the AhR in mediating toxicity, little is known about the physiological role of the AhR. Previous studies indicate that the AhR may regulate folliculogenesis, because AhR-deficient (AhRKO) mice have fewer preantral and antral follicles than wild-type (WT) mice during postnatal life. Thus, the first objective of the present study was to test the hypothesis that AhR deficiency reduces the numbers of preantral and antral follicles by slowing growth and/or increasing atresia of follicles. Because alterations in follicular growth or atresia can affect the ability to ovulate, the second objective was to test whether AhR deficiency reduces the number of ovulated eggs. To test these hypotheses, follicular growth was compared in WT and AhRKO ovaries using morphometric techniques and by measuring the ability of the ovary and follicles to grow in response to eCG. Atresia was compared in WT and AhRKO ovaries using morphometric techniques, TUNEL assays, and 3′-end labeling of fragmented DNA. Ovulation was compared in WT and AhRKO mice by assessing the number of corpora lutea per ovary. The results indicate that follicular growth and ovulation were reduced in AhRKO ovaries compared to WT ovaries. The WT ovaries had a 1.5-fold increase in the number of preantral and antral follicles between Postnatal Days 32 and 45, were more responsive to eCG, and contained more corpora lutea than AhRKO ovaries. In contrast, no significant difference was observed in the incidence of atresia in WT and AhRKO ovaries. Taken together, these results suggest that the AhR may regulate growth, but not atresia, of preantral and antral follicles in the mouse ovary.