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Ronald T Burkman

Publications and source records attributed to Ronald T Burkman.

At least 19 recordsLinked to original sources
PubMed2007

Risk of breast cancer associated with short-term use of oral contraceptives.

OBJECTIVE: To estimate breast cancer risk associated with short-term (<6 months) oral contraceptive use, and explore variation in estimates by use characteristics and medical, menstrual, and reproductive history. METHODS: We analyzed data from the Women's Contraceptive and Reproductive Experiences Study. Case subjects were white women and black women, 35-64 years old, diagnosed with invasive breast cancer in July 1994-April 1998. Control subjects identified by random-digit dialing were matched to case subjects by age, race, and study site. Conditional logistic regression was used to estimate odds ratios (ORs) and 95% confidence intervals (CIs). RESULTS: Overall, short-term oral contraceptive use was not associated with breast cancer risk (OR = 1.0; 95% CI = 0.8-1.1). However, significant interaction between short-term use and menopausal status led to an observed increased breast cancer risk in pre-menopausal women (OR = 1.3; 95% CI = 1.0-1.7) and a reduced risk in post-menopausal women (OR = 0.8; 95% CI = 0.6-1.0) associated with short-term use. The association was more pronounced in women with non-contraceptive reasons for use and underlying risk factors for breast cancer. CONCLUSIONS: These associations may result from underlying characteristics of users or unmeasured factors influencing duration of use and breast cancer risk.

Adult↗
PubMed2006

Prevalence and predictors of BRCA1 and BRCA2 mutations in a population-based study of breast cancer in white and black American women ages 35 to 64 years.

Although well studied in families at high-risk, the roles of mutations in the BRCA1 and BRCA2 genes are poorly understood in breast cancers in the general population, particularly in Black women and in age groups outside of the very young. We examined the prevalence and predictors of BRCA1 and BRCA2 mutations in 1,628 women with breast cancer and 674 women without breast cancer who participated in a multicenter population-based case-control study of Black and White women, 35 to 64 years of age. Among cases, 2.4% and 2.3% carried deleterious mutations in BRCA1 and BRCA2, respectively. BRCA1 mutations were significantly more common in White (2.9%) versus Black (1.4%) cases and in Jewish (10.2%) versus non-Jewish (2.0%) cases; BRCA2 mutations were slightly more frequent in Black (2.6%) versus White (2.1%) cases. Numerous familial and demographic factors were significantly associated with BRCA1 and, to a lesser extent, BRCA2 carrier status, when examined individually. In models considering all predictors together, early onset ages in cases and in relatives, family history of ovarian cancer, and Jewish ancestry remained strongly and significantly predictive of BRCA1 carrier status, whereas BRCA2 predictors were fewer and more modest in magnitude. Both the combinations of predictors and effect sizes varied across racial/ethnic and age groups. These results provide first-time prevalence estimates for BRCA1/BRCA2 in breast cancer cases among understudied racial and age groups and show key predictors of mutation carrier status for both White and Black women and women of a wide age spectrum with breast cancer in the general population.

Adult↗
PubMed2006

Breast cancer risk estimates for relatives of white and African American women with breast cancer in the Women's Contraceptive and Reproductive Experiences Study.

PURPOSE: Family history is a well-recognized risk factor for breast cancer. Familial aggregation and segregation analyses have estimated breast cancer risk based on family history primarily for white women; such information is limited for African American (AA) women. The purpose of this report is to update breast cancer risk estimates associated with a family history of breast cancer for white and AA women. METHODS: We used family cancer history from 2,676 white and 1,525 AA women with breast cancer (probands) in the population-based National Institute of Child Health and Human Development's Women's Contraceptive and Reproductive Experiences (CARE) Study to estimate age-specific breast cancer risks in their first degree adult female relatives. Cumulative hazard curves were calculated for relatives of all probands using Cox proportional hazards models, and were stratified by the proband's race and age at diagnosis and number of relatives affected. RESULTS: Breast cancer risks for white and AA women with a family history of the disease are similar through age 49 years, but diverge afterwards, with higher risks by age 79 in white women than in AA women (17.5% [SE, 0.9%] v 12.2% [SE, 1.1%]; P < .001). These risks increase as the number of affected first degree relatives increases, reaching 25.2% (SE, 3.4%) and 16.9% (SE, 4.0%) in white and AA women with more than one affected relative, respectively (P = .3). CONCLUSION: We found age-related racial differences in breast cancer risk in women with a family history of breast cancer and have updated risk estimates for white and AA women for clinical use.

Adult↗
PubMed2006

Relationship between established breast cancer risk factors and risk of seven different histologic types of invasive breast cancer.

BACKGROUND: Important differences in the contributions of certain exposures to the risks of ductal versus lobular breast carcinomas have been observed, but few studies have evaluated the relationships between established breast cancer risk factors and other histologic types. METHODS: Information on family history of cancer and reproductive, hormonal, anthropometric, and lifestyle characteristics were collected in a multicenter population-based case-control study consisting of 3,463 ductal, 274 lobular, 261 ductal-lobular, 91 medullary, 77 tubular, 70 comedo, and 61 mucinous invasive breast carcinoma cases (ages 35-64 years, newly diagnosed 1994-1998) and 4,682 controls. Associations between each of these histologic types and various exposures were evaluated using polytomous regression. RESULTS: Heterogeneity in the risks of different histologic types of breast cancer was observed for three exposures: menopausal hormone use, body mass index (BMI), and alcohol consumption. Specifically, current use of unopposed estrogen was associated with a reduced risk of ductal carcinoma and increased risk of comedocarcinoma, and current use of estrogen and progestin was associated with elevated risks of ductal-lobular and tubular carcinomas. Among postmenopausal women, BMI was only inversely related to risk of ductal-lobular carcinoma, and alcohol use was only positively related to risk of lobular carcinoma. CONCLUSIONS: Variations in the associations between known breast cancer risk factors and risk of different breast cancer histologies were observed. Although these findings require confirmation, and the analyses of some histologic groups were limited by small sample sizes, they provide some insight into the different etiologies of various histologic subtypes of breast cancer.

Adenocarcinoma, Mucinous↗
PubMed2005

Lifetime recreational exercise activity and breast cancer risk among black women and white women.

BACKGROUND: Physical inactivity is a potentially modifiable breast cancer risk factor. Because few data on this relationship exist for black women, we examined the relationship between breast cancer risk and lifetime and time- or age-specific measures of recreational exercise activity among white women and among black women. METHODS: The Women's Contraceptive and Reproductive Experiences Study was a multicenter population-based case-control study of black women and white women aged 35-64 years with newly diagnosed invasive breast cancer. We collected detailed histories of lifetime recreational exercise activity during in-person interviews with 4538 case patients with breast cancer (1605 black and 2933 white) and 4649 control subjects (1646 black and 3033 white). Control subjects were frequency-matched to case patients on age, race, and study site. We examined associations between exercise activity measures (metabolic equivalents of energy expenditure [MET]-hours per week per year) and breast cancer risk overall and among subgroups defined by race, other breast cancer risk factors, and tumor characteristics by use of unconditional logistic regression. All statistical tests were two-sided. RESULTS: Among all women, decreased breast cancer risk was associated with increased levels of lifetime exercise activity (e.g., average MET-hours per week per year, P(trend) = .002). An average annual lifetime exercise activity that was greater than the median level for active control subjects was associated with an approximately 20% lower risk of breast cancer, compared with that for inactivity (for 6.7-15.1 MET-hours/week/year, odds ratio [OR] = 0.82, 95% confidence interval [CI] = 0.71 to 0.93; for > or =15.2 MET-hours/week/year, OR = 0.80, 95% CI = 0.70 to 0.92). The inverse associations did not differ between black and white women (for MET-hours/week/year, P(trend) = .003 and P(trend) = .09, respectively; homogeneity of trends P = .16). No modification of risk was observed by disease stage, estrogen receptor status, or any breast cancer risk factor other than first-degree family history of breast cancer. CONCLUSIONS: This study supports an inverse association between physical activity and breast cancer among black women and among white women.

Adolescent↗
PubMed2005

Racial differences in the familial aggregation of breast cancer and other female cancers.

Although breast cancer familial aggregation has been studied in Caucasians, information for African-Americans is scant. We used family cancer history from the Women's Contraceptive and Reproductive Experiences study to assess the aggregation of breast and gynecological cancers in African-American and Caucasian families. Information was available on 41,825 first and second-degree relatives of Caucasian and 28,956 relatives of African-American participants. We used a cohort approach in which the relative's cancer status was the outcome in unconditional logistic regression and adjusted for correlated data using generalized estimating equations. Race-specific models included a family history indicator, the relative's age, and type. Relative risk (RR) estimates for breast cancer were highest for first-degree relatives, and the overall RR for breast cancer among case relatives was 1.96 (95% CI = 1.68-2.30) for Caucasian and 1.78 (95% CI = 1.41-2.25) for African-Americans. The effect of CARE participants' reference age on their relatives' breast cancer risk was greatest among first-degree relatives of African-American patients with RRs (95% CI) for ages <45 and > or =45 of 2.97 (1.86-4.74) and 1.48 (1.14-1.92), respectively. Among Caucasians, first-degree relatives of case subjects were at greater risk for ovarian cancer, particularly relatives younger than 45 years (RR (95% CI) = 2.06 (1.02-4.12)), whereas African-American first-degree relatives of case subjects were at increased cervical cancer risk (RR (95% CI) = 2.17 (1.22-3.85). In conclusion, these racially distinct aggregation patterns may reflect different modes of inheritance and/or environmental factors that impact cancer risk.

Adult↗
PubMed2005

Cost-effectiveness and contraceptive effectiveness of the transdermal contraceptive patch.

OBJECTIVE: The purpose of this study was to examine implications of increased perfect use on the cost-effectiveness of the contraceptive patch compared with combination oral contraceptives (COCs). STUDY DESIGN: This study compared the patch with low-estrogen-dose COCs. It assumes that the risks of developing a medical condition during use are the same for both the patch and COCs. Differences in net cost and pregnancies avoided during use were modeled. With the use of a pharmacoeconomic model, both methods were compared with a hypothetical reference case of contraception nonuse. The base-case model considered women, ages 15 to 50, in average health in a long-term, mutually monogamous, heterosexual relationship. RESULTS: The base-case analysis showed that use of the patch resulted in a savings of 249 US dollars and 0.03 pregnancies per woman over 2 years compared with COCs. CONCLUSION: This analysis demonstrated that patch use would be cost saving compared with COC use, resulting in a net avoidance of pregnancy for this population. The cost savings are attributed to reduced costs of pregnancy.

Administration, Cutaneous↗
PubMed2004

Reproductive factors and risk of breast carcinoma in a study of white and African-American women.

BACKGROUND: Few studies have investigated the association between reproductive factors and the risk of breast carcinoma among African-American women. The authors assessed whether the number of full-term pregnancies, age at first full-term pregnancy, and total duration of breastfeeding were associated with similar relative risk estimates in white and African-American women in a large multicenter, population-based case-control study of breast carcinoma. METHODS: Case patients were 4567 women (2950 white women and 1617 African-American women) ages 35-64 years with newly diagnosed invasive breast carcinoma between 1994 and 1998. Control patients were 4668 women (3012 white women and 1656 African-American women) who were identified by random-digit dialing and were frequency matched to case patients according to study center, race, and age. Adjusted odds ratios and 95% confidence intervals were estimated using unconditional logistic regression. RESULTS: For white women, the reduction in risk of breast carcinoma per full-term pregnancy was 13% among younger women (ages 35-49 years) and 10% among older women (ages 50-64 years). The corresponding risk reductions for African-American women were 10% and 6%, respectively. Risk decreased significantly with increasing number of full-term pregnancies for both races and both age categories. Duration of lactation was inversely associated with breast carcinoma risk among younger parous white (trend P = 0.0001) and African-American (trend P = 0.01) women. African-American women tended to have more children compared with white women, but parity rates were lower in younger women than in older women in both racial groups. However, breastfeeding was substantially more common in young white women than in young African-American women. CONCLUSIONS: Overall, parity and lactation had similar effects on breast carcinoma risk in white and African-American women. If younger African-American women now are giving birth to fewer children than in the past, without a substantial increase in breastfeeding, breast carcinoma rates may continue to increase at a more rapid rate among these women compared with white women.

Adult↗
PubMed2004

The transdermal contraceptive system.

The transdermal contraceptive system or contraceptive patch (Ortho EVRA, Ortho-McNeil Pharmaceuticals, Raritan, NJ), approved by the Food and Drug Administration in November 2001, is a novel combination hormonal contraceptive that contains the hormones norelgestromin and ethinyl estradiol. In clinical trials, the contraceptive patch was shown to have comparable safety and efficacy with that of oral contraceptives (OCs), and results indicated that the women who used the patch did so more correctly and consistently than those who used OCs. The enhanced patient compliance may be due to the once-a-week dosing and relative ease of use of this system. The transdermal delivery approach minimizes the "peaks and troughs" of hormone concentrations associated with daily oral administration and avoids hepatic first-pass metabolism. Side effects are similar to those seen with OCs with the exception of application site reactions that are obviously unique to transdermal delivery.

Administration, Cutaneous↗
PubMed2004

Absence of an effect of injectable and implantable progestin-only contraceptives on subsequent risk of breast cancer.

Animal data indicate that both estrogens and progestins could be carcinogenic and that progestins could serve as tumor promoters. Human studies have not confirmed an increased risk of breast cancer from long-term use of oral contraceptives, but have shown an increased risk from hormone replacement therapy including progestins. The present study analyzed the relationship between breast cancer and use of injectable and implantable progestin-only contraceptives. Analyses were performed on data collected in a population-based, multicenter, case-control study, the Women's Contraceptive and Reproductive Experiences Study of the National Institute of Child Health and Human Development. The study involved 4575 randomly sampled cases with invasive breast cancer diagnosed between 1994 and 1998, and 4682 controls, identified using random digit dialing. We assessed the association between exposure to injectable contraceptives and risk of breast cancer. The use of injectable contraceptives was not associated with an increased risk of breast cancer [odds ratio (OR) = 0.9, 95% confidence interval (CI): 0.7, 1.2]. Risk was not increased among current users, defined as women who used injectable contraceptives within 1 year of the reference date (OR = 0.7, 95% CI: 0.4, 1.3) or those who initiated use in the 5 years immediately preceding the reference date (OR = 0.9, 95% CI: 0.5, 1.4), or with use beginning before age 35 (OR = 0.9, 95% CI: 0.6, 1.3). Among users, risk increased with increasing duration of use (p = 0.03). However, short-term users (<6 months duration) were at decreased risk relative to never users (OR = 0.6, 95% CI: 0.4, 1.0). When the short-term users were then excluded from the duration-response analysis, the slope of the duration-response became slightly (and nonsignificantly) negative. Risk was not increased among women with 24 or more months of use relative to never users (OR = 1.4, 95% CI: 0.8, 2.5). No increased risk was seen from implantable contraceptives either, although the sample sizes were small. This study does not support an increased risk of breast cancer associated with the use of injectable or implantable progestin-only contraceptives in women aged 35 to 64.

Absorbable Implants↗
PubMed2004

Costs and net health effects of contraceptive methods.

BACKGROUND: Pregnancy and contraceptive methods both have important health effects that include risks and benefits. The net impact of contraception on women's health has not been reported previously. STUDY DESIGN: This is a cost-utility analysis using a Markov model evaluated by Monte Carlo simulation using the societal perspective for costs. The analysis compared 13 methods of contraception to nonuse of contraception with respect to healthcare costs and quality-adjusted life years (QALYs). Discounting was applied for future costs and health effects. The base-case analysis applies to women of average health and fertility, ranging from 15 to 50 years of age, who are sexually active in a mutually monogamous relationship; smoking rates observed in women of reproductive age were used. Sensitivity analysis extended the analysis to nonmonogamous status and smoking status. RESULTS: Compared with use of no contraception, contraceptive methods of all types result in substantial cost savings over 2 years, ranging from US$5907 per woman for tubal sterilization to US$9936 for vasectomy and health gains ranging from 0.088 QALYs for diaphragm to 0.147 QALYs for depot medroxyprogesterone acetate. Compared with nonuse, even with a time horizon as short as 1 year, use of any method other than sterilization results in financial savings and health gains. Most of the financial savings and health gains were due to contraceptive effects. In a population of patients, even modest increases in the use of the most effective methods result in financial savings and health gains. CONCLUSIONS: Every method of contraception dominates nonuse in most clinical settings. Increasing the use of more effective methods even modestly at the expense of less effective methods will improve health and reduce costs. Methods that require action by the user less frequently than daily are both less costly and more effective than methods requiring action on a daily basis.

Adolescent↗
PubMed2004

Chronic pelvic pain of bladder origin: epidemiology, pathogenesis and quality of life.

Interstitial cystitis (IC) is chronic pelvic pain of bladder origin that is far more common than previously thought. Although prevalence estimates vary greatly, studies consistently indicate that IC affects approximately 20% of women. The pathogenesis remains unknown but is thought to be multifactorial. Many women with IC have an abnormality of the bladder surface; ongoing exposure to urine solutes permeates the urothelium and causes significant pain and inflammation. The increased number of C-fibers and increased amount of substance P found in IC patients also contribute to the inflammation and pain associated with this condition. Long-standing and/or severe disease significantly impairs the ability to work and quality of life among IC patients. The physical and psychological consequences of IC should be a "call to arms" for clinicians to promptly and accurately diagnose and manage IC.

Chronic Disease↗
PubMed2004

Alcohol exposure and breast cancer: results of the women's contraceptive and reproductive experiences study.

OBJECTIVES: To explore associated biological outcomes and clarify the role of timing of exposure in the alcohol-breast cancer relationship. METHODS: In a population-based study of 4,575 women ages 35 to 64 years diagnosed with invasive breast cancer between 1994 and 1998 and 4,682 controls, we collected details of lifetime alcohol use and factors that could confound or modify the alcohol-breast cancer relationship. We used conditional logistic regression to compute the odds of breast cancer among drinkers relative to nondrinkers at all ages and at ages 35 to 49 and 50 to 64 years separately. RESULTS: Recent consumption (at reference age minus two) of >/=7 drinks per week was associated with increased risk [odds ratio (OR), 1.2; 95% CI, 1.01-1.3] and evidence of dose response was observed. Most of the excess was observed among women ages 50-64 years (OR 1.3; 95% CI, 1.1-1.6), although the test for age interaction was not statistically significant. Exposure later in life seemed more important than early exposure. Excess breast cancer associated with recent consumption was restricted to localized disease. When outcome was examined according to tumor hormone receptor status, highest risks were observed for estrogen receptor-positive/progesterone receptor-negative tumors (OR 1.6; 95% CI, 1.2-2.3). CONCLUSIONS: The effect of timing of alcohol exposure on breast cancer risk is complicated and will require additional study focused on this one issue. Further work is needed to explain how alcohol exposure, sex hormones, and tumor receptor status interact.

Adult↗
PubMed2003

Infertility drugs and the risk of breast cancer: findings from the National Institute of Child Health and Human Development Women's Contraceptive and Reproductive Experiences Study.

OBJECTIVE: To determine the association between infertility drug use and invasive breast cancer in a population-based case-control study. DESIGN: Multicenter case-control study. SETTING: Women aged 35 to 64 years in metropolitan Atlanta, Detroit, Los Angeles, Philadelphia, and Seattle. PATIENT(S): The 4,575 case patients had histologically confirmed primary invasive breast cancer. The 4,682 control subjects were women without breast cancer identified in the same geographic locations using randomized-digit dialing. INTERVENTION(S): A standardized questionnaire focusing on reproductive health and family history as well as use of oral contraceptives and other hormones and infertility drugs was administered to all subjects. Data on the type of breast cancer were also obtained. MAIN OUTCOME MEASURE(S): Odds ratios examining the association between use of various infertility drugs and invasive breast cancer. RESULT(S): Overall, a history of infertility drug use was not associated with the risk of developing breast cancer. Compared with women who never used any fertility medication, however, women using human menopausal gonadotropin (hMG) for > or = 6 months or for at least six cycles had a relative risk of breast cancer ranging between 2.7 to 3.8. CONCLUSION(S): Long-term use of certain infertility drugs could adversely affect risk of breast cancer. Additional confirmatory studies are needed.

Adult↗
PubMed2003

Combined effect of oral contraceptive use and hormone replacement therapy on breast cancer risk in postmenopausal women.

OBJECTIVE: We examined breast cancer risk related to lifetime exposure to oral contraceptives (OCs) and hormone replacement therapy (HRT) in postmenopausal women. METHODS: The Women's Contraceptive and Reproductive Experiences (CARE) Study was a population-based case-control study that included 1847 postmenopausal women with incident invasive breast cancer, and 1932 control subjects, identified using random digit dialing. RESULTS: 45% of cases and 49% of controls used both OCs and HRT. OC users were not at increased risk regardless of subsequent HRT exposure. HRT users who had used OCs previously did not have a higher risk of breast cancer than women with no exposure to OCs. We observed a negative interaction (p-value: 0.032) of combined hormone replacement therapy (CHRT) and past OC use. The increase in risk with CHRT was stronger in women who had never used OCs in the past (odds ratio: 1.05; 95% confidence interval: 1.01-1.10 per year of exclusive CHRT use) than in women who had used OCs (odds ratio: 1.00; 95% confidence interval: 0.97-1.03). CONCLUSIONS: We found no indication that adverse effects of exposure to OCs or HRT appeared only in the presence of the other hormone or were exacerbated by exposure to the other hormone.

Adult↗
PubMed2003

Association of regimens of hormone replacement therapy to prognostic factors among women diagnosed with breast cancer aged 50-64 years.

This study was conducted to assess the histopathological features of breast cancers in women diagnosed with breast cancer at 50-64 years of age who have and have not used hormone replacement therapy (HRT). A case-case analysis of the tumors from women aged 50-64 years who participated in a multicenter population-based case-control study of invasive breast cancer was conducted. In-person interviews collected a detailed history of all episodes of hormone use. Information was collected on selected tumor characteristics from 2346 women with breast cancer. Polytomous logistic regression was used to calculate the odds ratios (ORs) and 95% confidence intervals (CIs), contrasting the histopathological characteristics of the tumors of women who used various regimens of HRT with those of women who have never used HRT. The tumors of cases who used each regimen of HRT were smaller and of earlier stage than those of non-HRT users. Adjustment for screening diminished the magnitude of the effect, and only cases who used estrogen alone (estrogen replacement therapy) had reduced odds of being diagnosed with later-stage disease (regional or distant) than cases who never used HRT (OR, 0.7; 95% CI, 0.6-0.9). Higher proportions of estrogen receptor (ER)- and progesterone receptor (PR)-positive tumors were seen in cases who used any regimen of HRT versus those who did not use HRT. However, after adjustment for age and race, only the tumors of cases who used continuous combined HRT remained more likely to be ER+ and PR+ [OR ER- = 0.6 (95% CI, 0.4-0.9) and OR PR- = 0.5 (95% CI, 0.4-0.7)]. The tumors of women with breast cancer who used HRT have some better prognostic factors than those of women who have not used HRT. However, with the exception of the results noted above, this advantage may be due to the racial and age differences in those who use the various regimens of HRT and the effect of more frequent screening among HRT users, leading to earlier diagnosis.

Age Factors↗