A case-control study evaluating the association of purposeful physical activity, body fat distribution, and steroid hormones on premenopausal breast cancer risk

Muscle Strength, Body Composition, and Physical Activity in Women Receiving Chemotherapy for Breast Cancer

There is evidence to suggest that treatment of breast cancer with chemotherapy can induce metabolic changes in skeletal muscle. Women undergoing treatment for breast cancer with certain chemotherapeutic agents can experience declines in lean body mass and muscle strength and a subsequent increase in body weight. These alterations not only can lead to declines in physical function but also predispose women to weight-related chronic illness. Excess body weight may also play a role in the development or recurrence of breast cancer. There is evidence that physical exercise may improve body composition and enhance muscular endurance, flexibility, and quality of life (QOL) in women with breast cancer. While studies of aerobic, resistance, and combinations of aerobic and resistance exercise for women with breast cancer have been conducted, most studies employed supervised aerobic exercise sessions. Few studies have examined the role of resistance exercise or the combination of resistance and aerobic exercise in maintaining or increasing muscle strength while preserving lean body mass in this population. The relatively small sample sizes and short duration of physical activity interventions in previous studies make it difficult to detect dose responses to exercise training. Physical activity interventions with larger sample sizes and of longer duration are necessary to achieve long-term health outcomes. Physical activity interventions that include the older or more obese women with breast cancer are also needed, as this population may be most at risk of functional decline and the development of chronic illness. Interventions appropriate for women treated for breast cancer who have comorbid disease are also needed. Newer, more intense chemotherapy regimens may induce a differential effect on muscle strength and body composition. However, the role of physical activity during dose-dense chemotherapy protocols has not been established.

Running away from side effects: physical exercise as a complementary intervention for breast cancer patients

The number of breast cancer survivors increases every year, thanks to the development of new treatments and screening techniques. However, patients present with numerous side effects that may affect their quality of life. Exercise has been demonstrated to reduce some of these side effects, but in spite of this, few breast cancer patients know and follow the exercise recommendations needed to remain healthy. In this review, we describe the different breast cancer treatments and the related side effects and implications of exercise in relation to these. We propose that exercise could be an integrative complementary intervention to improve physiological, physical and psychological factors that affect survival and quality of life of these patients. For that reason, the main objective of this review is to provide a general overview of exercise benefits in breast cancer patients and recommendations of how to design exercise interventions in patients with different side effects.

Adults with greater weight satisfaction report more positive health behaviors and have better health status regardless of BMI

BACKGROUND

Prior studies suggest that weight satisfaction may preclude changes in behavior that lead to healthier weight among individuals who are overweight or obese.

OBJECTIVE

To gain a better understanding of complex relationships between weight satisfaction, weight-related health behaviors, and health outcomes.

DESIGN

Cross-sectional analysis of data from the Aerobics Center Longitudinal Study (ACLS).

PARTICIPANTS

Large mixed-gender cohort of primarily white, middle-to-upper socioeconomic status (SES) adults with baseline examination between 1987 and 2002 (n = 19,003).

MAIN OUTCOME VARIABLES

Weight satisfaction, weight-related health behaviors, chronic health conditions, and clinical health indicators.

STATISTICAL ANALYSES PERFORMED

Chi-square test, t-tests, and linear and multivariate logistic regression.

RESULTS

Compared to men, women were more likely to be dieting (32% women; 18% men) and had higher weight dissatisfaction. Men and women with greater weight dissatisfaction reported more dieting, yo-yo dieting, and snacking and consuming fewer meals, being less active, and having to eat either more or less than desired to maintain weight regardless of weight status. Those who were overweight or obese and dissatisfied with their weight had the poorest health.

CONCLUSION

Greater satisfaction with one's weight was associated with positive health behaviors and health outcomes in both men and women and across weight status groups.

A prospective study of cardiorespiratory fitness and breast cancer mortality

PURPOSE

Physical activity may protect against breast cancer. Few prospective studies have evaluated breast cancer mortality in relation to cardiorespiratory fitness (CRF), an objective marker of physiologic response to physical activity habits.

METHODS

We examined the association between CRF and risk of death from breast cancer in the Aerobics Center Longitudinal Study. Women (N = 14,811), aged 20 to 83 yr with no prior breast cancer history, received a preventive medical examination at the Cooper Clinic in Dallas, Texas, between 1970 and 2001. Mortality surveillance was completed through December 31, 2003. CRF was quantified as maximal treadmill exercise test duration and was categorized for analysis as low (lowest 20% of exercise duration), moderate (middle 40%), and high (upper 40%). At baseline, all participants were able to complete the exercise test to at least 85% of their age-predicted maximal heart rate.

RESULTS

A total of 68 breast cancer deaths occurred during follow-up (mean = 16 yr). Age-adjusted breast cancer mortality rates per 10,000 woman-years were 4.4, 3.2, and 1.8 for low, moderate, and high CRF groups, respectively (trend P = 0.008). After further controlling for body mass index, smoking, drinking, chronic conditions, abnormal exercise ECG responses, family history of breast cancer, oral contraceptive use, and estrogen use, hazard ratios (95% CI) for breast cancer mortality across incremental CRF categories were 1.00 (referent), 0.67 (0.35-1.26), and 0.45 (0.22-0.95) (trend P = 0.04).

CONCLUSIONS

These results indicate that CRF is associated with a reduced risk of dying from breast cancer in women.

How old are African American women when they receive their first mammogram? Results from a church-based study

African American women in the U.S. have the highest breast cancer mortality though not the highest breast cancer incidence. This high mortality rate has been attributed in part to discrepancies in screening between African American and White women. Although this gap in mammography utilization is closing, little is known about what has been and is driving the screening practices of African American women, in particular age at first mammogram. This study examined the rates of breast cancer screening in an African American community sample from eight churches in greater Baltimore, Maryland and investigated the association between various factors and age at first mammogram. Participants were 213 women ages 22-89 years. About 77% of women had ever had a mammogram. Over 40% had their first mammogram before age 40. Women who first screened before age 40 had greater odds than women who had never screened of being knowledgeable about screening guidelines, of having received a physician recommendation to screen, and of having three or more female relatives who had been screened. Women who first screened at or after age 40 were more likely to have stronger religious beliefs of health than women who never had screened. These findings suggest the importance of reinforcing factors in screening behavior for African American women and have implications for physician training and public health education about breast cancer screening. A better understanding of African American women's mammography practice including early screening is needed to reduce this population's disproportionate breast cancer mortality risk.

Body size, weight change, fat distribution and breast cancer risk in Hispanic and non-Hispanic white women

INTRODUCTION

The incidence of breast cancer varies among women living in the Southwestern part of the US. We evaluate how body size influences breast cancer risk among these women.

METHODS

Cases (n = 2,325) diagnosed with breast cancer between October 1, 1999 and May 2004 residing in Arizona, Colorado, New Mexico, or Utah were matched to controls (n = 2,525). Participants were interviewed; height, weight, waist, and hip circumference were measured at the time of interview; blood was drawn.

RESULTS

A large body mass index (BMI) at age 15 was inversely associated with pre-menopausal breast cancer risk in both non-Hispanic white (NHW) and Hispanic women (Odds ratio, ORs 0.68 95% CI 0.44, 1.04, and 0.65 95% CI 0.39, 1.08, respectively); BMI at age 15 also had an impact on subsequent breast cancer associated with obesity after menopause. Among post-menopausal women, recent exposure to hormones was an important modifier of risk associated with body size. Among women not recently exposed to hormones risk associated with obesity was 1.61 (95% CI 1.05, 2.45) for NHW women; gaining > or = 25 kg between 15 and age 50 was inversely associated with breast cancer among Hispanic women (OR 0.51, 95% CI 0.23, 1.14). A large weight gain and a large waist-to-hip ratio (WHR) was associated with an increased odds of having an estrogen receptor negative tumor among NHW only (OR 1.81, 95% CI 1.07, 3.08, and 2.04 95% CI 1.20,3.50).

CONCLUSIONS

These findings suggest that the metabolic consequences of obesity on breast cancer risk differ between NHW and Hispanic women living in the Southwest.

Physical activity and breast cancer risk among women in the southwestern United States

Physical activity may influence breast cancer risk through multiple mechanisms and at different periods in life. In this study we evaluate breast cancer risk associated with total and vigorous physical activity at ages 15, 30, and 50 years and the referent year prior to diagnosis/selection. Participants were non-Hispanic white (NHW) (1527 cases and 1601 control subjects) and Hispanic/American Indian (HAI) (798 cases and 924 controls) women. Both total and vigorous activity reduced risk of breast cancer in a dose-response manner. Among premenopausal women, only high total metabolic equivalent of the task (MET) hours of activity during the referent year was associated with reduced breast cancer risk in NHW women (odds ratio [OR] 0.62; 95% confidence interval [CI] 0.43, 0.91). Among postmenopausal women, physical activity had the greatest influence among women not recently exposed to hormones. Among these women, high total lifetime activity reduced risk of breast cancer for both NHW (OR 0.60; 95% CI 0.36, 1.02; p trend 0.01) and HAI women (OR 0.52; 95% CI 0.23, 1.16; p trend 0.07). Additionally, high total MET hours of activity at age 30 years (OR 0.56; 95% CI 0.37, 0.85) and at age 15 years (OR 0.57; 95% CI 0.38, 0.88) reduced breast cancer risk among postmenopausal NHW women not recently exposed to hormones. Among HAI women, more recent activity performed during the referent year and at age 50 appeared to have the greatest influence on breast cancer risk. Among postmenopausal NHW women. there was a significant interaction between physical activity and hormone replacement therapy (p value, 0.01), while among postmenopausal HAI women, physical activity interacted with body mass index (p value, 0.04). These data suggest that physical activity is important in reducing risk of breast cancer in both NHW and HAI women.