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Biomedical subjects

T L Bush

Publications and source records attributed to T L Bush.

At least 19 recordsLinked to original sources
PubMed2001

Relative androgen excess and increased cardiovascular risk after menopause: a hypothesized relation.

Many studies have investigated the role of estrogen during menopause; however, less attention has been paid to the role of androgen. Given the possible opposite effects of estrogen and androgen on cardiovascular disease risk, it is suggested that relative androgen excess may better predict the increased risk of cardiovascular disease in women over the age of 50 years than estrogen levels alone. Three phases of hormonal milieu changes are hypothesized as a better way to identify the hormone-cardiovascular disease risk association. A first phase, prepause, occurs before estrogen levels decline (approximately 2 years before menopause). A second phase, interpause, occurs from the end of prepause until approximately age 55. A third phase, postpause, occurs after interpause. The duration of the interpause phase, characterized by relative androgen excess, may be an independent risk factor of cardiovascular disease. This hypothesis could provide a basis for further clinical and epidemiologic research, and it could have important implications for establishing the initiation and duration of estrogen replacement therapy use as a means to prevent cardiovascular disease.

Aged↗
PubMed2001

Non-high-density lipoprotein cholesterol level as a predictor of cardiovascular disease mortality.

BACKGROUND: Non-high-density lipoprotein cholesterol (non-HDL-C) contains all known and potential atherogenic lipid particles. Therefore, non-HDL-C level may be as good a potential predictor of risk for cardiovascular disease (CVD) as low-density lipoprotein cholesterol (LDL-C). OBJECTIVES: To determine whether non-HDL-C level could be useful in predicting CVD mortality and to compare the predictive value of non-HDL-C and LDL-C levels. METHODS: Data are from the Lipid Research Clinics Program Follow-up Study, a mortality study with baseline data gathered from 1972 through 1976, and mortality ascertained through 1995. A total of 2406 men and 2056 women aged 40 to 64 years at entry were observed for an average of 19 years, with CVD death as the main outcome measure. RESULTS: A total of 234 CVD deaths in men and 113 CVD deaths in women occurred during follow-up. Levels of HDL-C and non-HDL-C at baseline were significant and strong predictors of CVD death in both sexes. In contrast, LDL-C level was a somewhat weaker predictor of CVD death in both. Differences of 0.78 mmol/L (30 mg/dL) in non-HDL-C and LDL-C levels corresponded to increases in CVD risk of 19% and 15%, respectively, in men. In women, differences of 0.78 mmol/L (30 mg/dL) in non-HDL-C and LDL-C levels corresponded to increases in CVD risk of 11% and 8%, respectively. CONCLUSIONS: Non-HDL-C level is a somewhat better predictor of CVD mortality than LDL-C level. Screening for non-HDL-C level may be useful for CVD risk assessment.

Adult↗
PubMed2001

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.

Breast Neoplasms↗
PubMed2001

SERMs and cardiovascular disease in women. How do these agents affect risk?

The beneficial effects of SERMs, specifically tamoxifen in the treatment and prevention of breast cancer and raloxifene in the prevention of osteoporosis, are well established. In addition, numerous groups of investigators have reported that these agents have a positive impact on cardiovascular health, possibly as a result of their cholesterol-lowering and anticoagulation actions. Although studies clearly showed that tamoxifen therapy improved the levels of some types of lipids, the changes did not appear to translate into a decreased risk of cardiovascular disease. However, the risk of thromboembolic events (as well as endometrial cancer) was increased with the use of tamoxifen, which is often prescribed for breast cancer prevention in healthy women. Similarly, raloxifene treatment had modest positive effects on cardiovascular risk factors but was associated with an increased risk of thromboembolism. When viewed as a whole, study results dictate that the benefits of SERM use for the prevention of cardiovascular disease be carefully weighed against the potential risks.

Blood Coagulation Factors↗
PubMed2000

Surveillance for uterine abnormalities in tamoxifen-treated breast carcinoma survivors: a community based study.

BACKGROUND: Tamoxifen-treated breast carcinoma survivors are at elevated risk of endometrial carcinoma. Whether to recommend annual surveillance for uterine abnormalities in this population is currently under debate. METHODS: This study was a cross-sectional, community-based investigation of tamoxifen use and the frequency of surveillance for endometrial carcinomas in 541 women with breast carcinoma. Study participants whose breast carcinoma was diagnosed in 1994 were interviewed in 1998. Data were collected from a telephone interview and from a cancer registry record. Tests for uterine abnormalities, based on participant reports of endometrial biopsy and transvaginal ultrasound, were categorized according to frequency. Testing for uterine abnormalities was defined as irregular if women reported tests once every 3 years, on average, and as regular, if they reported annual tests. RESULTS: Forty-nine percent of respondents were current tamoxifen users, 12% were former tamoxifen users, and 39% reported never taking tamoxifen. Of respondents with a uterus (n = 385), 19% reported irregular and 30% regular testing for uterine abnormalities after their breast carcinoma diagnosis. Respondents more frequently reported transvaginal ultrasound (37%) than endometrial biopsy (29%). Women 65 years of age and older were significantly less likely to report regular surveillance for uterine abnormalities (16%) than those younger than 65 years (35%). Current tamoxifen users more frequently reported regular surveillance (43%) than either former (35%) or never tamoxifen users (15%). Multivariable analyses showed tamoxifen users were more likely to have regular (odds ratio [OR], 9.8; 95% confidence interval [CI], 4.4-21.8) or to have irregular testing for uterine abnormalities (OR, 3.9; 95% CI, 1.9-8.1) compared with women who never used tamoxifen, after adjustment for age, number of recent gynecologic visits, and gynecologic symptoms. CONCLUSIONS: The results of the current study indicate that half of the breast carcinoma survivors in this population were tested for uterine abnormalities. Although at increased risk, 38% of tamoxifen users never had a test. Clear guidelines need to be established for the type and frequency of testing for uterine abnormalities among tamoxifen-treated breast carcinoma patients.

Adult↗
PubMed2000

Preserving cardiovascular benefits of hormone replacement therapy.

In the premenopausal period, the risk of heart disease is considerably lower in women than in men; however, in the postmenopausal period, when estrogen levels are considerably lower, women's risk of heart disease increases dramatically and approaches that of men. Numerous animal studies, using a variety of models, also confirm estrogen's cardioprotective effect. Although the results of numerous population-based, observational studies have demonstrated a lower risk of heart disease in women who receive estrogen replacement therapy, evidence from prospective, randomized clinical trials is scant. The Postmenopausal Estrogen/Progestin Intervention (PEPI) trial evaluated cardiovascular risk factors, not events, in a large, prospective, randomized trial and found that estrogen improved lipid profiles and other known risk factors. In addition, the PEPI trial compared several estrogen/progestogen treatment regimens, including both medroxyprogesterone acetate (MPA) and micronized progesterone (MP), and found that combined hormone replacement therapy regimens including MP attenuated the beneficial effects of estrogen less than those containing MPA. In the Heart and Estrogen/Progestin Replacement Study (HERS), however, which prospectively evaluated whether estrogen and MPA use reduced the number of nonfatal myocardial infarctions and cardiovascular events, no effect was seen. Although HERS was a null trial, the vast literature base showing a cardioprotective effect should not be discounted. Further research will be required before blanket recommendations on the cardioprotective effects of hormone therapy can be made.

Cardiovascular Diseases↗
PubMed1999

Low fibrinogen level: A predisposing factor for venous thromboembolic events with hormone replacement therapy.

Several studies have reported an association between hormone replacement therapy (HRT) in postmenopausal women and increased risk of idiopathic venous thromboembolic events (VTEs). Given the widespread use of HRT, it is important to identify factors that may predispose women on HRT to VTEs. To address this concern, we examined potential risk factors for VTEs in women assigned to HRT in the Postmenopausal Estrogen/Progestin Interventions (PEPI) study, a three-year, double-blinded, placebo-controlled trial of 875 postmenopausal women designed to assess the effects of HRT on heart disease risk factors (HDL cholesterol, fibrinogen, blood pressure, and insulin). Women with a history of estrogen-associated VTEs were excluded from the trial. Ten women, all assigned to HRT, had a VTE during PEPI. Only baseline fibrinogen varied significantly between those who did (mean = 249.0 mg/dl) and did not (mean = 280.8 mg/dl) have a VTE while assigned to HRT (P < 0.03). Adjusting for covariates including age, smoking, body mass index, lipid levels, blood pressure, alcohol, exercise, and prior HRT or oral contraceptive use did not affect this finding. The significantly lower fibrinogen levels seen among women subsequently reporting VTEs may be a marker for a specific, but as yet undefined, coagulopathy that is magnified in the presence of exogenous hormones. However, larger studies are needed to confirm this finding.

Afibrinogenemia↗
PubMed1998

Effect of postmenopausal hormone therapy on lipoprotein(a) concentration. PEPI Investigators. Postmenopausal Estrogen/Progestin Interventions.

BACKGROUND: Postmenopausal hormone therapy has been reported to decrease levels of lipoprotein (Lp)(a) in cross-sectional studies and small or short-term longitudinal studies. We report findings from a large, prospective, placebo-controlled clinical trial that allows a broad characterization of these effects for four regimens of hormone therapy. METHODS AND RESULT: The Postmenopausal Estrogen/Progestin Interventions study was a 3-year, placebo-controlled, randomized clinical trial to assess the effect of hormone regimens on cardiovascular disease risk factors in postmenopausal women 45 to 65 years of age. The active regimens were conjugated equine estrogens therapy at 0.625 mg daily, alone or in combination with each of three regimens of progestational agents: medroxyprogesterone acetate (MPA) at 2.5 mg daily (ie, continuous MPA), MPA at 10 mg days 1 to 12 (ie, cyclical MPA), and micronized progesterone at 200 mg days 1 to 12. Plasma levels of Lp(a) were measured at baseline (n = 366), 12 months (n = 354), and 36 months (n = 342). Assignment to hormone therapy resulted in a 17% to 23% average drop in Lp(a) concentrations relative to placebo (P<.0001), which was maintained across 3 years of follow-up. No significant differences were observed among the four active arms. Changes in Lp(a) associated with hormone therapy were positively correlated with changes in LDL cholesterol, total cholesterol, apolipoprotein B, and fibrinogen levels and were similar across subgroups defined by age, weight, ethnicity, and prior hormone use. CONCLUSIONS: Postmenopausal estrogen therapy, with or without concomitant progestin regimens, produces consistent and sustained reductions in plasma Lp(a) concentrations.

Aged↗
PubMed1998

Clomiphene analogs with activity in vitro and in vivo against human breast cancer cells.

Six hundred triphenylethylenes were assayed for antiproliferative activity against MCF-7, LY2, and MDA-MB-231 breast cancer cells using sulforhodamine B dye to measure proliferation. Here we report on just 63 of the compounds, mostly clomiphene analogs, with substitutions on the alpha' or beta ring, at the vinyl position or in the side chain, of which 23 were active, as defined by antiproliferation IC50 values < or =1 microM. Activity profiles showed that 23 and 11 analogs were active toward MCF-7 and LY2, respectively, but none were active against MDA-MB-231. The IC50 values of tamoxifen were 2.0 microM against MCF-7 and 7.5 microM against LY2 and MDA-MB-231. Estradiol reversed antiproliferative activities of several E isomers but not their Z isomer counterparts. Clomiphene side chain analogs 46 [(E)-1-butanamine, 4-[4-(2-chloro-1,2-diphenylethenyl) phenoxy]-N,N-diethyl-dihydrogen citrate (MDL 103,323)] and 57 [(E)-N-[p-(2-chloro-1,2-diphenylvinyl) phenyl]-N,N-diethylethylenediamine dihydrogen citrate (MDL 101,986)] were 4- to 5-fold more effective than tamoxifen. Methylene additions up to (-CH2-)12 in the clomiphene side chain showed that analog 46 [(-CH2-)4 side chain] had maximal antiproliferative activity, binding affinity, and inhibition of transcription of an estrogen response element luciferase construct in transfected MCF-7 cells. Intraperitoneal administration of 46 or 57 inhibited progression of MCF-7 breast tumor xenografts in nude mice with ED50 values of <0.02 mg/mouse/day. Both analogs may hold promise for treating ER positive breast cancer and are of interest for further development.

Animals↗
PubMed1998

Racial differences in drug metabolism: an explanation for higher breast cancer mortality in blacks?

The risk of dying from breast cancer differs between racial groups, and the reason for this racial difference is unknown. In this paper, we hypothesize that racial differences in breast cancer mortality may be due to racial differences in the metabolism of drugs used to treat women with breast cancer. Racial differences in the metabolism and effectiveness of other commonly used drugs have been described, and these differences are thought to result from genetic differences in the cytochrome P450 enzyme system. Tamoxifen, widely used for breast cancer treatment, is metabolized by the cytochrome P450 system. Preliminary evidence from human studies suggests that this agent is less effective in non-whites than whites; however, more definitive studies are needed. A better understanding of racial differences in cytochrome P450 drug metabolism and subsequent effectiveness will lead to better breast cancer treatment for all women.

Antineoplastic Agents↗
PubMed1998

Breast cancer mortality in black and in white women: a historical perspective by menopausal status.

To examine racial/ethnic differences in breast cancer mortality over time by menopausal status, data from published U.S. Vital Statistics tables (1950-1992) and the Surveillance, Epidemiology, and End Results Program of the National Cancer Institute (1973-1991) were used to calculate age-adjusted breast cancer mortality and incidence rates. Overall, breast cancer mortality rates for white women were relatively stable from 1950 to 1992. In contrast, breast cancer mortality rates for black women increased during this period. Among premenopausal women there was no difference in breast cancer mortality between black and white women from 1950 to about 1975. However, after 1975, mortality rates in black premenopausal women increased, whereas those in white women decreased. Among postmenopausal women, breast cancer mortality was substantially lower in blacks than in whites in 1950. Between 1950 and 1992, rates in blacks increased and eventually exceeded rates in whites, which remained stable during this period. This excess in breast cancer mortality in black women is not explained by changes in breast cancer incidence rates. There is an unexplained epidemic of breast cancer mortality in black women that appears to differ somewhat by menopausal status. Reasons for temporal increases in breast cancer mortality seen only among black women need to be identified, as do reasons for the heterogeneity of trends by menopausal status.

Adult↗
PubMed1998

Predictors of menopausal hot flashes.

There are limited data on the factors associated with menopausal hot flashes, a common and potentially morbid condition. The objective of this study was to identify predictors of menopausal hot flashes. To meet this objective, 233 naturally perimenopausal or post-menopausal women (ages 45-65) attending a large urban hospital center primary care clinic, mammography unit, or women's health practice were enrolled. The women responded to a self-administered questionnaire assessing selected demographic factors, reproductive history, and behavioral factors. Sixty-seven percent of respondents experienced hot flashes, with 63% reporting frequent hot flashes (at least one hot flash per day) and 60% with hot flashes describing the hot flashes as severe. Women with hot flashes were significantly more likely to have mothers who experienced hot flashes (OR = 4.4, CI = 2.0-10.0) or to be smokers (OR = 2.0, CI = 1.2-3.5). There were no statistically significant associations between hot flashes and other selected demographic, reproductive, or behavior characteristics. These results reveal that menopausal hot flashes are associated with a maternal history of hot flashes as well as with cigarette smoking. These results may help physicians to counsel their patients about smoking cessation.

Aged↗
PubMed1998

Agreement in assessing endometrial pathology: the Postmenopausal Estrogen/Progestin Interventions (PEPI) Trial.

We report on agreement in interpreting endometrial biopsy specimens between the local and central pathologists of the Postmenopausal Estrogen/Progestin Interventions (PEPI) trial. This trial was a 3-year, multicenter, randomized, double-masked, placebo-controlled trial of four groups taking estrogen or estrogen/progestin combinations. A total of 1804 follow-up biopsies were performed in 596 subjects. Relative sensitivity and relative specificity using the diagnosis from the central pathologist as the gold standard and overall agreement are presented. Almost 90% of the diagnoses were reported normal by both readers. There were significant differences in agreement among clinics and treatment arms (p < 0.0001). The visit at which the biopsy specimen was obtained, age at baseline, prior postmenopausal estrogen use, parity, and drug adherence were not associated with agreement between the two readers. Higher proportions of disagreement were seen in two clinics (13% and 11%) compared with the other five clinics (2%-5%). Biopsy specimens from participants who were taking conjugated equine estrogens (CEE) only were more likely to be diagnosed differently by both readers (11%) than biopsy specimens from women taking a placebo (2%) or CEE combined with progestins (5%). Relative specificity varied from 86.4% to 98.9% among the clinics (p < 0.0001). Relative sensitivity was based on a small number of diagnoses, as few biopsy specimens were classified abnormal by the central pathologist. In patients assigned to CEE combined with progestin, 5 of the 7 biopsy specimens that were recorded abnormal by the central pathologist received a normal diagnosis locally. Our findings show that sample size requirements for study designs in which a central reader is used can be at least threefold lower than the requirements for designs relying on local diagnoses. Centralized protocols for endometrial histopathology reading and staff training are highly desirable in multicenter trials.

Biopsy↗