Associations between energy balance and body mass index and risk of breast carcinoma in women from diverse racial and ethnic backgrounds in the U.S

Association of serum adiponectin with breast cancer: A meta-analysis of 27 case-control studies

BACKGROUND

Emerging published studies have indicated that adiponectin is involved in tumorigenesis of breast cancer. However, the results of available studies were inconsistent. The aim of this updated meta-analysis was to assess the association of adiponectin with breast cancer.

MATERIALS AND METHODS

PubMed, EMBASE, Wanfang databases, and the China National Knowledge Infrastructure (CNKI) were systematically searched from inception to June 2018. The mean difference (MD) with 95% confidence interval (CI) were estimated and pooled to investigate the effect sizes.

RESULTS

Twenty-seven eligible articles that met the study criteria were included in the current meta-analysis. Overall, there was an evident inverse association between serum adiponectin levels and breast cancer (MD = -0.29, 95%CI = (-0.38, -0.21), P < .001). Asian subgroup showed a significant negative association between serum adiponectin concentrations and breast cancer in subgroup analysis by ethnicity (MD = -2.19, 95%CI = (-3.45, -0.94), P < .001). However, no statistical significance was found in Caucasian subgroup (MD = -0.65, 95%CI = (-1.47, 0.17), P = 0.12). Additionally, a further subgroup analysis of Asian stratified by menopausal status showed higher concentrations of adiponectin in healthy control group, whether they were premenopausal (MD = -0.85, 95%CI = (-1.50, -0.19), P = .01) or postmenopausal (MD = -2.17, 95%CI = (-4.17, -0.18), P = .03). No significant difference was observed concerning the association between serum adiponectin and breast cancer metastasis (MD = -1.56, 95%CI = (-4.90, 1.78), P = .36).

CONCLUSION

The current meta-analysis suggests that the serum adiponectin may be inversely associated with breast cancer. Decreased serum adiponectin levels in premenopausal women may also be inversely associated with breast cancer risk other than postmenopausal status. In addition, low serum adiponectin levels in Asian women were more likely to be associated with breast cancer risk than Caucasian women.

Comparative Study of Serum Lipid Profiles in Nepalese Cancer Patients Attending a Tertiary Care Hospital

Significant efforts have been made to study cancer at the biochemical and cellular level and identify factors associated with progression. The aim of this hospital based randomized comparative study at the Nepalese Army Institute of Health science hospital was to assess factors in 52 people diagnosed with different types of cancer and 56 normal control persons. Fasting blood samples were analyzed for serum total cholesterol (TC), high density lipoprotein (HDL), triglycerides (TG) and low density lipoprotein (LDL). We found that biochemical parameter TC, TG, VLDL (very low density lipoprotein), LDL and HDL were significantly different in the cancer patients and healthy controls. Levels of TC, TG, LDL, HDL and VLDL were higher in the age group below 50 and that of TG was found to be higher in women than men. Our results indicate that TC, TG and HDL are increased, while LDL and VLDL are lowered in cancer patients. Our study provides clues to risk factors associated with life style, eating habits, and exercise regimens. Monitoring of these parameters with aging is recommended.

Deciphering metabolic rewiring in breast cancer subtypes

Metabolic reprogramming, an emerging hallmark of cancer, is observed in breast cancer. Breast cancer cells rewire their cellular metabolism to meet the demands of survival, proliferation, and invasion. However, breast cancer is a heterogeneous disease, and metabolic rewiring is not uniform. Each subtype of breast cancer displays distinct metabolic alterations. Here, we focus on unique metabolic reprogramming associated with subtypes of breast cancer, as well as common features. Therapeutic opportunities based on subtype-specific metabolic alterations are also discussed. Through this discussion, we aim to provide insight into subtype-specific metabolic rewiring and vulnerabilities that have the potential to better guide therapy and improve outcomes for patients.

Dietary Energy Density and Postmenopausal Breast Cancer Incidence in the Cancer Prevention Study II Nutrition Cohort

BACKGROUND

Dietary energy density (ED) is a measure of diet quality that estimates the amount of energy per unit of food (kilocalories per gram) consumed. Low-ED diets are generally high in fiber and fruits and vegetables and low in fat. Dietary ED has been positively associated with body mass index (BMI) and other risk factors for postmenopausal breast cancer.

OBJECTIVE

We evaluated the associations of total dietary ED and energy-dense (high-ED) foods with postmenopausal breast cancer incidence.

METHODS

Analyses included 56,795 postmenopausal women from the Cancer Prevention Study II Nutrition Cohort with no previous history of breast or other cancers and who provided information on diet, lifestyle, and medical history in 1999. Multivariable-adjusted breast cancer incidence rate ratios (RRs and 95% CIs) were estimated for quintiles of total dietary ED and for the consumption of high-ED foods in Cox proportional hazards regression models.

RESULTS

During a median follow-up of 11.7 y, 2509 invasive breast cancer cases were identified, including 1857 estrogen receptor-positive and 277 estrogen receptor-negative tumors. Median dietary ED was 1.5 kcal/g (IQR: 1.3-1.7 kcal/g). After adjusting for age, race, education, reproductive characteristics, and family history, high compared with low dietary ED was associated with a statistically significantly higher risk of breast cancer (RR for fifth quintile compared with first quintile: 1.20; 95% CI: 1.05, 1.36; P-trend = 0.03). The association between the amount of high-ED foods consumed and breast cancer risk was not statistically significant. We observed no differences by estrogen receptor status or effect modification by BMI, age, or physical activity.

CONCLUSION

These results suggest a modest positive association between total dietary ED and risk of postmenopausal breast cancer.

Resistin, visfatin, adiponectin, and leptin: risk of breast cancer in pre- and postmenopausal saudi females and their possible diagnostic and predictive implications as novel biomarkers

The mechanisms of obesity-induced breast carcinogenesis are not clear. One hypothesis is that high levels of adipokines could promote breast cancer (BC) development. The aim of this study was to investigate the correlation of resistin, visfatin, adiponectin, and leptin with BC risk in pre- and postmenopausal females. A total of 82 BC newly diagnosed and histologically confirmed patients and 68 age and BMI matched healthy controls were enrolled. Both groups were subdivided into post- and premenopausal subgroups. Resistin, visfatin, adiponectin, and leptin were measured by ELISA. There were significantly higher levels of leptin, resistin, and visfatin in postmenopausal BC patients than their respective controls. Only in postmenopausal subgroups, leptin, resistin, and visfatin levels were positively correlated with TNM staging, tumor size, lymph node (LN) metastasis, and histological grading. In postmenopausal females, multivariate logistic regression analysis revealed that adiponectin, leptin, visfatin, and resistin were risk factors for BC. Our results suggested that serum resistin, leptin, adiponectin, and visfatin levels as risk factors for postmenopausal BC may provide a potential link with clinicopathological features and are promising to be novel biomarkers for postmenopausal BC.

Benign Breast Diseases and Body Mass Index: Is There a Correlation?

Breast cancer is the leading cancer affecting women in America. Body mass index (BMI) is a known risk factor for the development of breast cancer. The relationship of BMI to benign breast disease is less clear. In addition, certain benign pathologies are associated with an increased risk of cancer. We sought to measure the incidence of benign pathologies and to correlate these findings with BMI and age. All patients undergoing breast biopsy at our center from 2000 to 2005 were identified (n = 1717). Age, BMI, family history, sex, and diagnosis were determined. Patients were grouped into BMI, age, and intervention groups. χ2 ( P < 0.05) was used to identify statistical significance. Fibrocystic disease and fibroadenoma were seen with a lower incidence for patients older than 55 years of age, whereas pathologies requiring further surgical intervention were seen in higher proportions in patients older than 55 years of age. All pathologies were noted to decrease with increasing BMI, except for fibroadenoma, which peaked in BMI group 25 to 29.9 kg/m2. The presence of benign pathologies was associated with age as expected. Interestingly, although BMI is associated with increased risk of breast cancer, increasing BMI was not associated with benign pathologies that are associated with increased risk of breast cancer. Further study of this area is warranted.

American Cancer Society Guidelines on nutrition and physical activity for cancer prevention: reducing the risk of cancer with healthy food choices and physical activity

The American Cancer Society (ACS) publishes Nutrition and Physical Activity Guidelines to serve as a foundation for its communication, policy, and community strategies and, ultimately, to affect dietary and physical activity patterns among Americans. These Guidelines, published approximately every 5 years, are developed by a national panel of experts in cancer research, prevention, epidemiology, public health, and policy, and they reflect the most current scientific evidence related to dietary and activity patterns and cancer risk. The ACS Guidelines focus on recommendations for individual choices regarding diet and physical activity patterns, but those choices occur within a community context that either facilitates or creates barriers to healthy behaviors. Therefore, this committee presents recommendations for community action to accompany the 4 recommendations for individual choices to reduce cancer risk. These recommendations for community action recognize that a supportive social and physical environment is indispensable if individuals at all levels of society are to have genuine opportunities to choose healthy behaviors. The ACS Guidelines are consistent with guidelines from the American Heart Association and the American Diabetes Association for the prevention of coronary heart disease and diabetes, as well as for general health promotion, as defined by the 2010 Dietary Guidelines for Americans and the 2008 Physical Activity Guidelines for Americans.

A walking intervention for postmenopausal women using mobile phones and Interactive Voice Response

We conducted a feasibility study of a 12-week walking intervention administered through an Interactive Voice Response (IVR) system and mobile phones. We also examined the added benefit of a human coach. Post-menopausal women (n = 71) were given a daily-steps goal, which they monitored using a pedometer. Each day, they answered an automated call from the IVR system to their mobile phone and provided assessments of walking goals and mood. Every evening, they called the IVR system to report their steps, answered a brief questionnaire and received a message with a helpful hint. Participants took less time to complete a one-mile walk after the intervention, compared to baseline (0.77 min, SE = 0.22, P < 0.001). In addition, a significant loss in body weight (0.93 kg, SE = 0.31) and body-mass index (0.28 kg/m(2), SE = 0.11) were observed. The key psychometric measures of exercise goal setting (0.67 units, SE = 0.12) and exercise planning (0.48 units, SE = 0.09) also improved from baseline (both P < 0.001). However, results in the coach and no-coach conditions were not significantly different. The study suggests that mobile phones can be used to deliver an effective, low-cost walking intervention, irrespective of the addition of a human coach.

An observational study of the prevalence and incidence of comorbid conditions in older women with breast cancer

Background

Longitudinal analyses of comorbid conditions in women with breast cancer are few.

Methods

Using Surveillance, Epidemiology, and End Results–Medicare data, we included 51 950 women aged ≥66 years with in situ and stage I to IV breast cancer diagnosed in 1998–2002. We identified the prevalence and incidence of 34 comorbid conditions in these women, as well as in a matched cohort without cancer whose rates were standardized to the age and race/ethnicity distribution of the cancer patients. We also estimated rates of office encounters and diagnostic or testing procedures during the 12 months before diagnosis.

Results

The prevalence of most conditions at diagnosis was comparable among breast cancer and noncancer patients. New conditions after diagnosis were more common in breast cancer patients, and the incidence rates increased with higher stage at diagnosis. Before diagnosis, women presenting with stage IV disease had 41% [95% confidence interval (CI) 38% to 43%] fewer physician encounters and 34% (95% CI 24% to 31%) fewer unique diagnostic tests than women diagnosed with carcinoma in situ.

Conclusions

Many comorbid conditions are identified as a consequence of the breast cancer diagnosis. There appears to be an important contribution from a lack of interaction with the health care system before diagnosis.

Obesity is associated with breast cancer in African-American women but not Hispanic women in South Los Angeles

BACKGROUND

Obesity is considered a risk factor for breast cancer. Modifying life styles that reduce obesity offers the potential for prevention and improved outcomes from cancer. The effects of obesity and breast cancer among African-American women and Hispanic women have been explored in a limited number of studies. The objective of the current study was to investigate the association of obesity with breast cancer in a minority cohort.

METHODS

This was a cross-sectional study of 471 African-American and Hispanic women with and without breast cancer in South Los Angeles. Data regarding body mass index (BMI) and clinical factors were obtained by medical record abstraction. Data were assessed using logistic regression with multivariate analysis. Kaplan-Meier survival analysis was used to assess disease-free survival.

RESULTS

Women with breast cancer were more likely to be obese (BMI >30 kg/m(2)) than women without breast cancer (odds ratio [OR], 2.0; P = .01). There was a significant association of being overweight or obese and breast cancer among postmenopausal women (OR, 2.3 [P = .03] and 2.9 [P < .01], respectively). The association between obesity and breast cancer was significant only among African-American women (OR, 2.70; P < .01) and was especially significant among postmenopausal African-American women (OR, 4.8; P < .01). There was a borderline significant association between obesity and later disease stage at diagnosis (P = .06). An association also was observed between higher BMI (for cutoff points of both 30 kg/m(2) and 28 kg/m(2)) and poorer disease-free survival (P = .045 and P = .019, respectively).

CONCLUSIONS

The current data suggested an association between obesity and breast cancer, especially among postmenopausal women and most significantly in the African-American cohort.

Obesity, body fat distribution and breast cancer

Abstract Strong epidemiological data exists implicating anthropometric risk factors in breast cancer aetiology. In premenopausal women the risk of breast cancer increases with increased height, yet decreases with increasing weight and BMI. Although the evidence is not strong, a counter-intuitive positive relationship between central adiposity and premenopausal breast cancer risk is emerging. In post-menopausal women an increased risk in breast cancer has been found for all anthropometric measures: height, weight, BMI, measures of central adiposity (waist:hip ratio and waist circumference) and weight gain, with breast size being a possible additional risk factor. Weight loss as a strategy for reducing breast cancer risk seems to offer a viable prophylaxis in obese post-menopausal women, although data are limited. The evidence for anthropometric measures in relation to breast cancer risk is consistently stronger for post-menopausal women compared with premenopausal women and seems to be dependent on age. A number of possible biological mechanisms have been offered to explain the link between breast cancer risk and anthropometric measures. It has been hypothesised that obesity, especially central fat deposits, linked to insulin resistance, increases circulating hormones such as oestrogens, androgens, insulin, insulin-like growth factor-1 (IGF-1), and decreased levels of hormone-binding proteins such as steroid hormone-binding globulin and IGF-1 binding protein-1. Thus there are resulting increased concentrations of bioavailable sex hormones, which have been linked to increased breast cancer risk. As obesity is an important modifiable risk factor, which has been linked to increased post-menopausal breast cancer, public health recommendations to maintain ideal weight throughout life are warranted.

Minireview: Obesity and breast cancer: the estrogen connection

There is now substantial evidence that overweight and/or obesity and/or weight gain are risk factors for the development of postmenopausal breast cancer. In addition, obesity and/or elevated body mass index at breast cancer diagnosis has a negative impact on prognosis for both premenopausal and postmenopausal women. Therefore, understanding the mechanism of how obesity affects the mammary tumorigenesis process is an important health issue. Elevated serum estrogen levels as well as enhanced local production of estrogen have been considered primary mediators of how increased body weight promotes breast cancer development in postmenopausal women. Here, we provide an overview of estrogen's relationship with both obesity and breast cancer as separate entities. Human and relevant preclinical studies are cited. In addition, other growth factors that may be involved in this relationship are considered.

Strategic health communication across the continuum of breast cancer care in limited-resource countries

Strategic health communication is a critical component of healthcare that should be implemented across the continuum of care. Recognizing the importance of communication strategies and incorporating such strategies into healthcare policies, programs, and interventions is essential to the effective delivery of breast cancer care. The authors reviewed relevant literature and suggested practical evidence-based strategies for effective communication interventions across the continuum of care for breast cancer patients, including early detection, diagnosis, treatment, survivorship, palliative care, and end-of-life care. Examples were provided from limited-resource nations to support health communication recommendations.

Leptin utilizes Jun N-terminal kinases to stimulate the invasion of MCF-7 breast cancer cells

In breast tumors, high levels of leptin have been associated with increased incidence of breast cancer metastasis. Breast cancer metastasis is directly associated with breast cancer cell invasion. However, whether leptin could augment breast cancer cell invasion is not known. Here we showed that leptin increased the invasiveness and the matrix metallo-proteinase-2 (MMP-2) activity of the MCF-7 breast cancer cell line. Leptin stimulated the phosphorylation of extracellular signals regulated kinases, signal transducers and activators of transcription 3 and Jun N-terminal kinases (JNK); however, only inhibition of JNK decreased leptin-mediated activation of MMP-2. Furthermore, inhibition of JNK suppressed leptin-mediated breast cancer cell invasion. Here we report the novel findings that leptin increased invasion of breast cancer cells by activating JNK, resulting in increased MMP-2 activity.

Somatotype and risk of breast cancer: a case-control study in Uruguay

According to the evidence, there is a need for more thorough assessment and quantification of body size and shape and the risk of breast cancer. Using the somatotype methodology, we carried out an original research in order to explore possible associations between body shape and the risk of breast cancer in Uruguayan women. With this objective, 254 recent breast cancer cases and 1,000 frequency-matched healthy controls were interviewed on menstrual and reproductive story, and a series of skinfolds, circumferences and diameters were measured specifically to calculate somatotype. A positive association with breast cancer was found for high endomorphy (Odds Ratio [OR] = 2.82, p < 0.001), mainly among pre-menopausal women (OR = 4.98, p <0.001) and normoweight women (OR = 5.12, p = 0.002), whereas almost no differences were observed for mesomorphic and ectomorphic women. Analysis showed a high meso-endomorphic pattern in the study population. Further studies are needed to confirm the present results obtained in a country with high incidence of the disease.

Barriers to adequate follow-up during adjuvant therapy may be important factors in the worse outcome for Black women after breast cancer treatment

Introduction

Black women appear to have worse outcome after diagnosis and treatment of breast cancer. It is still unclear if this is because Black race is more often associated with known negative prognostic indicators or if it is an independent prognostic factor. To study this, we analyzed a patient cohort from an urban university medical center where these women made up the majority of the patient population.

Methods

We used retrospective analysis of a prospectively collected database of breast cancer patients seen from May 1999 to June 2006. Time to recurrence and survival were analyzed using the Kaplan-Meier method, with statistical analysis by chi-square, log rank testing, and the Cox regression model.

Results

265 female patients were diagnosed with breast cancer during the time period. Fifty patients (19%) had pure DCIS and 215 patients (81%) had invasive disease. Racial and ethnic composition of the entire cohort was as follows: Black (N = 150, 56.6%), Hispanic (N = 83, 31.3%), Caucasian (N = 26, 9.8%), Asian (N = 4, 1.5%), and Arabic (N = 2, 0.8%). For patients with invasive disease, independent predictors of poor disease-free survival included tumor size, node-positivity, incompletion of adjuvant therapy, and Black race. Tumor size, node-positivity, and Black race were independently associated with disease-specific overall survival.

Conclusion

Worse outcome among Black women appears to be independent of the usual predictors of survival. Further investigation is necessary to identify the cause of this survival disparity. Barriers to completion of standard post-operative treatment regimens may be especially important in this regard.

Birthweight and body size throughout life in relation to sex hormones and prolactin concentrations in premenopausal women

The association of birthweight and body size throughout life with premenopausal breast cancer risk may be due, in part, to relationships with sex hormones. Therefore, we assessed whether birthweight, body shape at ages 5 and 10, body mass index (BMI) at age 18 and adulthood, adult waist circumference and waist-to-hip ratio (WHR), and attained height were associated with the plasma concentrations of estrogens, androgens, progesterone, prolactin, and sex hormone-binding globulin (SHBG) in 592 premenopausal women, ages 33 to 52 years old, from the Nurses' Health Study II. About 85% of women provided blood samples during follicular and luteal menstrual phases; other women had a single untimed sample. We observed few associations between sex hormone levels and birthweight or body shape in childhood. However, adult BMI was inversely associated with SHBG (P trend < 0.001) and positively associated with free testosterone (P trend < 0.001) concentrations. Adult BMI was not associated with follicular or luteal free estradiol levels (P trend >or= 0.15) because it was inversely associated with total estradiol levels (P trend < 0.001 for follicular and luteal estradiol levels). Testosterone, androstenedione, and progesterone were inversely associated with BMI. Comparing women with a BMI of >or=30 versus <20 kg/m2, levels were higher by 53% for free testosterone and lower by 51% for SHBG, 39% for follicular estradiol, 20% for luteal estradiol, 14% for androstenedione, 13% for testosterone, and 20% for progesterone. We observed no clear associations between BMI at age 18, waist circumference, WHR, or height, and sex hormone concentrations. Our results suggest that effects on premenopausal sex hormone levels may be one mechanism through which adult adiposity, but not birthweight or childhood body size, affects premenopausal breast cancer risk.

Association of energy intake and energy balance with postmenopausal breast cancer in the prostate, lung, colorectal, and ovarian cancer screening trial

Energy restriction remains one of the most effective ways known to prevent breast cancer in animal models. However, energy intake has not been consistently associated with risk of breast cancer in humans. In a prospective study, we assessed whether energy intake, body size, and physical activity each independently influence breast cancer risk in postmenopausal women and estimated the joint effect of combinations of these individual factors. As part of the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial, 38,660 women, ages 55 to 74 years and recruited from 10 centers in the United States during 1993 to 2001, were randomized to the screening arm of the trial. At baseline, the women completed a self-administered questionnaire, including a food frequency questionnaire. During follow-up from 1993 to 2003, 764 incident breast cancer cases were ascertained. Women in the highest quartile of energy intake (> or = 2,084 kcal/d) compared with those in the lowest quartile (<1,316 kcal/d) had a significantly increased risk for breast cancer [multivariate relative risk (RR), 1.25; 95% confidence interval (95% CI), 1.02-1.53; P(trend continuous) = 0.03]. Current body mass index (BMI) was also positively and significantly associated with risk (multivariate RR comparing >30 kg/m2 with <22.5 kg/m2, 1.35; 95% CI, 1.06-1.70; P(trend) = 0.01). Women with > or = 4 hours/wk of vigorous recreational physical activity had a significantly reduced risk of breast cancer compared with those who reported no recreational physical activity (multivariate RR, 0.78; 95% CI, 0.60-0.99; P(trend) = 0.15). None of these associations with individual energy balance measures was substantially confounded by the other two measures. When we estimated the joint effect of all three variables, women with the most unfavorable energy balance (the highest energy intake, highest BMI, and least physical activity) had twice the risk (RR, 2.10; 95% CI, 1.27-3.45) of women with the most favorable energy balance (the lowest energy intake, lowest BMI, and most physical activity). Although our estimates of absolute energy intake, based on a food frequency questionnaire, are imperfect, these results suggest that energy intake, in addition to BMI and physical activity may be independently associated with breast cancer risk. In addition, these three aspects of energy balance may act jointly in determining breast cancer risk.

Measures of adiposity and risk of breast cancer in older postmenopausal women

OBJECTIVES

To determine whether higher adiposity is associated with greater breast cancer risk in older postmenopausal women.

DESIGN

Prospective cohort study with mean follow-up of 11.3 years.

SETTING

Four U.S. clinical centers.

PARTICIPANTS

Seven thousand five hundred twenty-three women (mean age 73.5) enrolled in the Study of Osteoporotic Fractures.

MEASUREMENTS

Weight, height, and waist and hip circumference were measured at baseline. Body composition was determined using bioelectrical impedance. Risk factor information was obtained by interview and questionnaire. Bone mineral density was measured using dual energy x-ray absorptiometry. The outcome was incident invasive breast cancer, confirmed using medical records.

RESULTS

After adjustment for multiple risk factors, including bone density, women in the uppermost quartiles of weight, weight gain since age 25, body mass index, waist circumference, and percentage of body fat had higher breast cancer rates than women in the first quartiles of each measure. For example, breast cancer rates were 49% higher for women in the uppermost quartile of weight (hazard ratio (HR)=1.49, 95% confidence interval (CI)=1.05-2.10), 64% higher for women in the top quartile of weight gain since age 25 (HR=1.64, 95% CI=1.15-2.34), and 58% higher for women in the top quartile of percentage of body fat (HR=1.58, 95% CI=1.11-2.23) than for women in the lowest quartile of each measure. The associations between adiposity measures and breast cancer rates were not altered when the analyses were limited to very elderly women (> or = 70).

CONCLUSION

Higher adiposity is an independent risk factor for breast cancer in elderly women.

Obesity, hormone therapy, estrogen metabolism and risk of postmenopausal breast cancer

Hormone therapy (HT) and body mass index (BMI) have been associated with postmenopausal breast cancer. Because estrogen metabolism may affect breast cancer risk and can be altered by weight and HT, it might play a role in the HT-BMI-breast cancer associations. We undertook a nested case-control study within the Observational Study of the Women's Health Initiative. Baseline levels of 2- and 16alpha-hydroxy estrone (2-OHE1 and 16alpha-OHE1) were measured in 200 women who developed breast cancer during follow-up and 200 healthy controls matched to cases by ethnicity, enrollment date, clinic site, type of HT and years since menopause. Wilcoxon nonparametric tests were used to compare estrogen metabolite levels between cases and controls. Conditional logistic regression was used to assess the relationship between BMI, estrogen metabolites and breast cancer risk. 16alpha-OHE1 levels were modestly but significantly higher in HT users among cases (median 356 pg/ml vs. 315 pg/ml) and controls (354 pg/ml vs. 298 pg/ml). 2-OHE1 levels were substantially and significantly higher in HT users among cases (369 pg/ml vs. 125 pg/ml) and controls (347 pg/ml vs. 134 pg/ml). For non-HT users only, greater BMI and higher 16alpha-OHE1 levels were individually and jointly associated with increased breast cancer risk (OR for women with high BMI and high 16alpha-OHE1 compared to those with low BMI and low 16alpha-OHE1 = 3.51, 95% CI = 1.34-9.16). No associations between BMI, estrogen metabolism and breast cancer risk were found for HT users. Estrogen metabolism differs according to both BMI and HT use, potentially explaining the interaction between BMI and HT in relation to breast cancer risk.

Nutrition, Lifestyle, and Breast Cancer Risk Among Turkish Women

Breast cancer is the most common malignancy in women, with more than 1 million cases occurring worldwide annually. Cancer is one of the leading causes of mortality in Turkey; deaths due to breast cancer constitute 24.1% of all carcinoma cases reported among women. We conducted a case-control study of Turkish women with and without breast cancer to investigate the relationships of selected lifestyle and nutritional risk factors with breast cancer risk. Factors were chosen based upon published associations with breast cancer. Subjects were women in Izmir, Turkey. Cases were 123 women with breast cancer registered with the Department of Oncology, Ege University Hospital, in February through July 2004. The control group included 120 randomly selected women without a breast cancer diagnosis, registered with the Evka-4 Health Care Center and having similar sociodemographic characteristics. Inclusion criteria for participation consisted of 40 yr of age and over and willingness to participate. Chi2 tests and t-tests were used to determine statistical differences between cases and controls based on selected variables. Logistic regression was used to find the association between selected risk factors and breast cancer occurrence. Cases had smoked for more years, their age of first pregnancy was higher, and breast cancer occurrence was more common in first-degree relatives such as mothers and sisters of cases compared with controls. Cases were found to have consumed higher amounts of vegetable oil in contrast to controls. These findings are consistent with similar studies conducted in both developed and developing countries.

Racial and ethnic disparities in breast cancer: a multilevel perspective

Although the etiology of racial and ethnic disparities in breast cancer is complex, the studies reviewed here suggest many possible culprits. In the authors' model, outcomes at the cellular level reflect not only genetic constitution and the hormonal milieu but also the interactions of predictors at multiple levels. At the societal level, important predictors include toxin and hormone exposure, access to care, quality of care, and social support. At the individual level, reproductive history, exogenous hormone use, diet,exercise, and response to stress all may influence cellular outcomes. The smooth transition from normal cell function to apoptosis occurs when the interactions between factors at the societal, individual, and cellular levels are harmonious. Perturbations at the societal level, however, such as inferior quality of care, or at the individual level, such as exogenous hormone use,can have profound effects on cell biology and predispose to neoplasia. When these perturbations are systematic and vary by race or ethnicity, disparities in breast cancer incidence and mortality result. Increasing incidence of breast cancer among both men and women likely reflects important trends at the societal and individual levels. These trends may include increased toxin exposure, increased obesity, and changes in the timing and number of births. Efforts to reduce breast cancer incidence and disparities must consider societal and individual factors and the important effects these factors can have on normal cell function.

Sedentarism: a concept analysis

TOPIC

Concept analysis of sedentarism.

PURPOSE

To analyze the concept of sedentarism and provide a definition and model of sedentarism to guide practice and research.

SOURCES

Published literature.

CONCLUSIONS

Prevention and treatment of sedentarism is a priority for healthcare providers serving all developmental groups. Research is urgently needed to describe the prevalence, risk factors, and consequences of sedentarism, and to identify the most effective intervention strategies and public policy changes to promote a physically active lifestyle.

A combined breast health/weight loss intervention for Black women

BACKGROUND

Overall incidence of breast cancer is slightly lower, but mortality rates are higher, for Black women compared to White women. Higher body mass index (BMI), sedentary lifestyles, and lower compliance with recommended breast health behaviors may contribute to higher risk and mortality.

METHODS

A randomized pilot intervention trial was conducted to assess feasibility and efficacy of a combined breast health/weight loss intervention for 64 overweight or obese Black women, ages 35-65. The primary objectives were to determine whether a 20-week (twice weekly) intervention could decrease weight and dietary fat intake and increase physical activity and breast self-exam (BSE) proficiency.

RESULTS

The project was implemented in two cohorts and retention was high for both (96% and 89%, respectively). Both cohorts showed increased proficiency in BSE in the intervention versus the control group (2.4 vs. -0.4, P<0.05; 3.3 vs. -0.2, P<0.001, respectively), but only cohort 2 showed decreased percent body weight (4.0% decrease vs. 0.9% increase, P<0.01), increased physical activity frequency (2.4 vs. 0.1 times/week, P<0.05), and a trend for decreased dietary fat (-2.6% kcal vs. 0.0% kcal, P=0.07) in the intervention compared to the control group.

CONCLUSION

Few studies have documented weight loss among Black women, and no combined breast health/weight loss intervention has been conducted. This study documents the feasibility of recruiting, randomizing, and retaining women in a combined intervention and demonstrated weight loss and associated lifestyle changes.

Cancer risk-reduction behaviors of breast cancer survivors

Using secondary data analysis, the aim was to determine if postmenopausal women, who have survived breast cancer, have adopted healthy nutritional and physical activity behaviors recommended in the American Cancer Society guidelines as cancer risk-reduction strategies, and in guidelines for prevention of other chronic diseases or for improving general health. From their personal health history, women who have survived breast cancer would be likely candidates to adopt healthy behaviors recommended as cancer risk-reduction strategies or for prevention of other chronic diseases. A secondary aim was to determine the perceived general health and affective state of these women. These breast cancer survivors had a high perception of their general health, a positive affective state, and have adopted some healthy lifestyle behaviors, but they are not fully adhering to the ACS nutrition and physical activity guidelines or other health related guidelines for cancer risk reduction or prevention of other chronic diseases.

Diet-Induced Obesity and Mammary Tumor Development in MMTV-neu Female Mice

Obesity is a risk factor for postmenopausal breast cancer and is associated with shortened latency and/or increased mammary tumor (MT) incidence in animals. Elevated body weight is usually associated with hormone-responsive tumors. In agreement with these data we previously showed that latency of hormone-responsive MTs in MMTV-TGF-alpha mice with diet-induced obesity was significantly shortened. Here, we used the same protocol to determine the impact of diet-induced obesity on estrogen receptor-negative MT development in MMTV-neu (strain 202) mice. Mice were fed a low-fat diet (n=20) or a high-fat diet (n=54) from 10 wk of age. Body weight at 19 wk of age was used to assign high-fat mice to obesity-prone, overweight, and obesity-resistant groups. Mice were euthanized due to MT size or at 85 wk of age. Final body weights of obesity-prone mice were heaviest, and those of obesity-resistant and low-fat groups were similar. Fat pad weights were heaviest in obesity-prone mice followed by overweight and obesity-resistant groups, and lightest in low-fat mice. Serum IGF-I levels were similar for low-fat and high-fat mice, whereas leptin was higher in high-fat mice (P <0.0001). MT latency, incidence, metastasis, and burden were similar for all groups. These findings support that obesity is not a risk factor for development of estrogen-negative breast cancer.

Breast cancer size in postmenopausal women is correlated with body mass index and androgen serum levels

Our objective was to investigate the effects of age, weight, body mass index (BMI), sex steroid receptor status and serum parameters such as estradiol, testosterone, androstenedione, dehydroepiandrosterone sulfate (DHEAS) and leptin on the size of a malignant breast tumor. A total of 62 premenopausal (median age 44.0 years) and 151 postmenopausal (median age 59.1 years) Caucasian women undergoing lumpectomy or mastectomy for invasive breast cancer were examined. Patient parameters (age, body weight, BMI), tumor parameters (tumor size, estrogen and progesterone receptor status) and serum parameters (estradiol, testosterone, androstenedione, DHEAS and leptin) were measured. An increase of BMI and DHEAS levels was associated with larger tumors by partial correlation (rp) analysis (rp = 0.418, p = 0.008; and rp = 0.329, p = 0.041, respectively), whereas higher androstenedione levels corresponded with smaller tumors. Furthermore, BMI, androstenedione and DHEAS levels were correlated: an increase in DHEAS was associated with higher androstenedione serum concentrations (rp = 0.603, p < 0.001), but was also associated with a lower BMI (rp = -0.378, p < 0.001). BMI and androstenedione serum concentrations were also associated (rp = 0.242, p = 0.009), thus closing a circle of mutual interactions. We conclude that, although breast cancer progression is characterized by autonomous growth that has become independent of growth regulatory mechanisms, tumor size at the time of detection is influenced by a complex system of counter-regulatory feedback mechanisms that might represent the body's physiological attempt to control the size of a malignant tumor.

Behavioral risk factors in breast cancer: can risk be modified?

The International Agency for Research on Cancer estimates that 25% of breast cancer cases worldwide are due to overweight/obesity and a sedentary lifestyle. The preponderance of epidemiologic studies indicates that women who engage in 3-4 hours per week of moderate to vigorous levels of exercise have a 30%-40% lower risk for breast cancer than sedentary women. Women who are overweight or obese have a 50%-250% greater risk for postmenopausal breast cancer. Alcohol use, even at moderate levels (two drinks per day) increases risk for both premenopausal and postmenopausal breast cancer. Certain dietary patterns, such as high fat, low vegetables/fruits, low fiber, and high simple carbohydrates, may increase risk, but definitive data are lacking. These lifestyle factors are likely associated with breast cancer etiology through hormonal mechanisms. The worldwide trends of increasing overweight and obesity and decreasing physical activity may lead to an increasing incidence of breast cancer unless other means of risk reduction counteract these effects. Thus, adoption of lifestyle changes by individuals and populations may have a large impact on the future incidence of this disease.

Breast cancer risk and lifestyle differences among premenopausal and postmenopausal African-American women and white women

BACKGROUND

Very little is known about the role of lifestyle in breast cancer risk, and even less is known about whether differences in lifestyle contribute to the disparities in this risk between African-American women and white women. In this study, the authors examined differences in diet and physical activity between African-American women and white women and discuss the research that is needed regarding the role of lifestyle in breast cancer risk.

METHODS

The authors used bivariate and multiple regression analyses to estimate the difference between African-American women and white women in body mass index (BMI), physical activity, the Healthy Eating Index, intake of selected nutrients, and serum levels of some micronutrients. Data were taken from the National Health and Nutrition Examination Survey III, 1988-1994.

RESULTS

African-American women had a higher BMI, and older African-American women were less active physically compared with white women. African-American women of all ages had a poorer quality diet, and they consumed more protein and cholesterol but less dietary fiber, folate, and vitamin A. African-American women had lower predicted serum levels of folate and vitamin A but higher predicted serum levels of lutein.

CONCLUSIONS

The current findings generally are consistent with the hypothesis that nutrition differences may contribute to the higher rate of breast cancer experienced by younger African-American women, although extensive research is needed. More longitudinal data and research on nutrition, genetics, and breast cancer among African-American women are needed. Studies should examine how to help African-American women make behavioral changes to reduce their risk of breast cancer.

African-American ethnicity, socioeconomic status, and breast cancer survival: a meta-analysis of 14 studies involving over 10,000 African-American and 40,000 White American patients with carcinoma of the breast

BACKGROUND

African-American women are at increased risk for breast cancer mortality compared with white American women, and the extent to which socioeconomic factors account for this outcome disparity is unclear.

METHODS

A MEDLINE search was conducted to identify published studies that used a Cox proportional hazards regression model to evaluate the outcome of African-American women and white American women with breast carcinoma after adjusting for socioeconomic status. A meta-analysis was performed using specialized statistical software; the random-effects method of statistical evaluation was used because of the a priori impression that the studies reviewed would be at least moderately heterogeneous in study design and patient populations.

RESULTS

The initial literature search yielded 3962 studies. Fourteen studies met all criteria for inclusion in the meta-analysis, resulting in a sample size of 10,001 African-American patients and 42,473 white American patients with breast carcinoma. There was substantial variation in the method used for defining socioeconomic status. Summary statistics revealed a significant odds ratio of 1.22 (95% confidence interval, 1.13-1.30) for the adverse effect of African-American ethnicity on breast cancer mortality. Subset meta-analyses yielded similar results, supporting the robustness of this finding.

CONCLUSIONS

This meta-analysis revealed that African-American ethnicity is an independent predictor of a worse breast cancer outcome. The pooled analysis has added strength because of the aggregate sample size and indicates that the true biologic and/or therapeutic determinants of disparities in breast cancer outcome for different ethnic groups and for different socioeconomic strata are incompletely understood.

Is obesity a risk factor for prostate cancer, and does it even matter? A hypothesis and different perspective

Measurement of obesity is not as simple as its definition. Currently, several methods of measuring obesity are used in clinical studies. Skinfold thickness, crude weight, lean body mass (LBM), body mass index (BMI), and waist-to-hip ratio (WHR) are some of the more popular methods, but each contains its inherent strengths and flaws. In general, the results of the largest studies on prostate cancer and obesity have not been conclusive. One of the largest studies found an inverse relation to prostate cancer in the youngest age groups. The age and duration of obesity or any rapid changes in weight gain, along with other unhealthy exposures, may have some relation to prostate cancer incidence and mortality. Early intrinsic or extrinsic exposure to estrogen or estrogenlike compounds may provide a protective effect. The timing and duration of a higher estrogen and/or lower testosterone exposure may have a beneficial or detrimental impact on the prognosis of an established prostate tumor. Negative exposures over time such as low levels of sex hormone-binding globulin (SHBG), a greater exposure to growth factors, elevated insulin levels, greater sympathetic activity, higher cholesterol levels, immune system dysfunction, inadequate diets, smoking status, and other factors may be associated with an increased risk of prostate cancer and other diseases. Obesity may also be associated with other cancers for similar and different reasons. For example, morbidity and mortality from postmenopausal breast cancer, colon, kidney, and other cancers are potentially associated with obesity. Other comorbidities such as cataracts, coronary heart disease, diabetes, erectile dysfunction, hypertension, and others are also associated with obesity. The 2 largest prospective studies on BMI and overall mortality have also demonstrated the substantial negative impact of excess weight on society. Prostate cancer risk and obesity need further research to establish if a true association exists, but at this time, does it really matter? Overall, the profound adverse effect of being obese on general health is dramatic, and this is what clinicians and patients need to remember.

Identifying and counseling women at increased risk for breast cancer

Women at increased risk for breast cancer should be identified and counseled about options for risk reduction. Identifying such women is simplified with use of the National Cancer Institute Risk Assessment tool, a computer-based tool that incorporates information on 6 risk factors for estimating an individual's risk of developing breast cancer. However, the tool does not incorporate all known or possible risk factors and may underestimate risk, particularly among women with a complex family history of breast cancer for whom alternative models of risk assessment are more appropriate. Women found to have an increased risk of breast cancer should be counseled about options for management, including close surveillance, lifestyle modifications, chemoprevention with tamoxifen, enrollment in a breast cancer prevention clinical trial, and prophylactic mastectomy and/or oophorectomy. In the absence of consensus about which risk level is best suited to which option, decisions about risk reduction depend as much on an individual's priorities and risk aversion as on numerical risk estimates.

Changes and tracking of physical activity across seven years in Mexican-American and European-American mothers

Longitudinal changes in physical activity among 129 Mexican-American (mean age 30.8; SD = 5.6) and 97 European-American (mean age 31.2; SD = 5.4) women were studied. Two physical activity recall interviews were administered at baseline and 7 years later. At baseline, European-American women reported more vigorous leisure activity (p < .005) than Mexican-Americans, and Mexican-Americans reported more moderate work activity (p < .02) than European-Americans. Virtually all components of physical activity increased significantly over the 7 years. Pearson tracking correlations for total energy expenditure were about r = 0.30. The finding that both groups increased physical activity overtime was unexpected and was unrelated to a reduction in the number of preschool children in the homes over time.

Diet and environmental carcinogenesis in breast/gynaecological cancers

This paper reports on recent advances on the relation between diet, other environmental factors and breast and gynaecological cancers. Despite considerable research the issue remains still unsettled. The protective effect of a diet rich in vegetables and fruit, and thus selected (antioxidant) micronutrients, is not consistently reported in various studies. The possible relationship between fats and breast and female genital tract neoplasms also remains unconfirmed, while the potential benefits of physical activity remains unquantified. Alcohol appears to be related to the risk of breast cancer and overweight is associated with post-menopausal breast cancer and is strongly related to the risk of endometrial cancer.

Breast cancer prevention: present and future

Increased risk of breast cancer may result from modifiable factors such as endogenous hormone levels, obesity, HRT, and non-lactation, or non-modifiable factors such as genetic susceptibility or increasing age. Those factors that are easiest to modify may have a limited impact on the totality of breast cancer. The Gail model, based on known factors may be useful for estimating life-time risk in some individuals. Tamoxifen prevention still remains contentious. In the NSABP-P1 study, there was a 49% reduction in risk of breast cancer in women given tamoxifen but in the Italian and Royal Marsden trials, no effect on breast cancer incidence was detected, possibly because of the different case-mix in these studies. Raloxifene, tested in the MORE trial reduced the incidence of breast cancer by 65%. The effect was restricted to ER positive tumours: no reduction in ER negative cancers was seen. Life-style factors such as diet, obesity, exercise, and age of first full term pregnancy and number of pregnancies have a mild to moderate impact on risk and so may have little effect on the incidence of breast cancer. Reduction of alcohol intake could lead to a modest reduction in the risk of breast cancer but possibly adversely affect other diseases. So far, studies of retinoids have not shown a benefit in terms of breast cancer risk reduction. Fat reduction and GnRH analogues reduce mammographic density but have not yet been shown to affect risk.

Diet and cancer prevention

Research from several sources provides strong evidence that vegetables, fruits, and whole grains, dietary fibre, certain micronutrients, some fatty acids and physical activity protect against some cancers. In contrast, other factors, such as obesity, alcohol, some fatty acids and food preparation methods may increase risks. Unravelling the multitude of plausible mechanisms for the effects of dietary factors on cancer risk will likely necessitate that nutrition research moves beyond traditional epidemiological and metabolic studies. Nutritional sciences must build on recent advances in molecular biology and genetics to move the discipline from being largely 'observational' to focusing on 'cause and effect'. Such basic research is fundamental to cancer prevention strategies that incorporate effective dietary interventions for target populations.

Review of anthropometric factors and breast cancer risk

Epidemiological evidence implicating anthropometric risk factors in breast cancer aetiology is accumulating. For premenopausal women, breast cancer risk increases with increasing height, but decreases with higher weight or body mass index, and no association with increased central adiposity exists. For postmenopausal women, an increased risk of breast cancer is found with increasing levels of all the anthropometric variables including height, weight, body mass index, waist-hip ratio, waist circumference and weight gain. Weight loss appears to decrease risk, particularly if it occurs later in life. Breast size may be a risk factor for breast cancer, however, the current evidence is inconclusive. Several hypothesized biologic mechanisms exist to explain how anthropometric factors influence breast cancer risk. Obesity may increase levels of circulating endogenous sex hormones, insulin and insulin-like growth factors that all, in turn, increase breast cancer risk. Genetic predisposition to obesity and to specific body fat distributions are also implicated. With obesity, there are increased levels of fat tissue that can store toxins and can serve as a continuous source of carcinogens. Recommendations for future research on anthropometric factors and breast cancer are provided. Sufficient evidence exists to support strategies to avoid weight gain throughout life as a means of reducing postmenopausal breast cancer risk.

Breast cancer--can risks really be lessened?

Breast cancer, although uncommon in western populations in the past, continues to rise in incidence, and now affects up to one woman in nine. In some countries, such as the US and Australia, the mortality rate is decreasing, albeit slightly. In developing populations, while of low occurrence, the disease is rising in incidence. Risk factors, which include certain reproductive practices, diet and physical activity, while apparent in some contexts, appear much less so in others; moreover, the avoiding measures do not lend themselves to primary prevention. For early detection, although regular mammography is advocated, it is a subject of controversy. Basically, avoiding measures fall within the usual recommendations for a 'prudent' lifestyle - avoid obesity, increase physical activity, stop smoking and restrict alcohol consumption.