Showing papers by "Melinda L. Irwin published in 2009"

Randomized controlled trial of aerobic exercise on insulin and insulin-like growth factors in breast cancer survivors: the Yale Exercise and Survivorship study.

Abstract: Background: High insulin and insulin-like growth factor-I (IGF-I) levels may be associated with an increased breast cancer risk and/or death. Given the need to identify modifiable factors that decrease insulin, IGF-I, and breast cancer risk and death, we investigated the effects of a 6-month randomized controlled aerobic exercise intervention versus usual care on fasting insulin, IGF-I, and its binding protein (IGFBP-3) in postmenopausal breast cancer survivors. Methods: Seventy-five postmenopausal breast cancer survivors were identified from the Yale-New Haven Hospital Tumor Registry and randomly assigned to an exercise ( n = 37) or usual care ( n = 38) group. The exercise group participated in 150 minutes per week of moderate-intensity aerobic exercise. The usual care group was instructed to maintain their current physical activity level. A fasting blood sample was collected on each study participant at baseline and 6 months. Blood levels of insulin and IGF were measured with ELISA. Results: On average, exercisers increased aerobic exercise by 129 minutes per week compared with 45 minutes per week among usual care participants ( P < 0.001). Women randomized to exercise experienced decreases in insulin, IGF-I, and IGFBP-3, whereas women randomized to usual care had increases in these hormones. Between-group differences in insulin, IGF-I, and IGFBP-3 were 20.7% ( P = 0.089), 8.9% ( P = 0.026), and 7.9% ( P = 0.006), respectively. Conclusions: Moderate-intensity aerobic exercise, such as brisk walking, decreases IGF-I and IGFBP-3. The exercise-induced decreases in IGF may mediate the observed association between higher levels of physical activity and improved survival in women diagnosed with breast cancer. (Cancer Epidemiol Biomarkers Prev 2009;18(1):306–13)

Exercise improves body fat, lean mass and bone mass in breast cancer survivors

Abstract: Given the negative effects of a breast cancer diagnosis and its treatments on body weight and bone mass, we investigated the effects of a 6-month randomized controlled aerobic exercise intervention vs. usual care on body composition in breast cancer survivors. Secondary aims were to examine the effects stratified by important prognostic and physiologic variables. Seventy-five physically inactive postmenopausal breast cancer survivors were recruited through the Yale-New Haven Hospital Tumor Registry and randomly assigned to an exercise (n = 37) or usual care (n = 38) group. The exercise group participated in 150 min/week of supervised gym- and home-based moderate-intensity aerobic exercise. The usual care group was instructed to maintain their current physical activity level. Body composition was assessed at baseline and 6-months through dual-energy X-ray absorptiometry (DXA) by one radiologist blinded to the intervention group of the participants. On an average, exercisers increased moderate-intensity aerobic exercise by 129 min/week over and above baseline levels compared with 45 min/week among usual care participants (P < 0.001). Exercisers experienced decreases in percent body fat (P = 0.0022) and increases in lean mass (P = 0.047) compared with increases in body fat and decreases in lean mass in usual care participants. Bone mineral density (BMD) was also maintained among exercisers compared with a loss among usual care participants (P = 0.043). In summary, moderate-intensity aerobic exercise, such as brisk walking, produces favorable changes in body composition that may improve breast cancer prognosis.

Exercise and quality of life during and after treatment for breast cancer: results of two randomized controlled trials

Abstract: Objective: To determine the effect of exercise on quality of life in (a) a randomized controlled trial of exercise among recently diagnosed breast cancer survivors undergoing adjuvant therapy and (b) a similar trial among post-treatment survivors. Methods: Fifty newly diagnosed breast cancer survivors were recruited through a hospital-based tumor registry and randomized to a 6-month, home-based exercise program (n=25) or a usual care group (n=25). In a separate trial, 75 post-treatment survivors were randomized to a 6-month, supervised exercise intervention (n=37) or to usual care (n=38). Participants in both studies completed measures of happiness, depressive symptoms, anxiety, stress, self-esteem, and quality of life at baseline and 6 months. Results: Forty-five participants completed the trial for newly diagnosed survivors and 67 completed the trial for post-treatment survivors. Good adherence was observed in both studies. Baseline quality of life was similar for both studies on most measures. Exercise was not associated with quality of life benefits in the full sample of either study; however exercise was associated with improved social functioning among post-treatment survivors who reported low social functioning at baseline (p<0.05). Conclusions: Exercise did not affect quality of life in either recently diagnosed or post-treatment breast cancer survivors; however this may be due in part to relatively high baseline functioning among participants in both studies. Strategies for future research include limiting enrollment to survivors who report reduced quality of life on screening questionnaires and targeting survivor subgroups known to be at particular risk for quality of life impairment. Copyright © 2009 John Wiley & Sons, Ltd.

Race/ethnicity, physical activity, and quality of life in breast cancer survivors.

Abstract: Purpose: To examine associations between recreational physical activity and quality of life (QOL) in a multiethnic cohort of breast cancer survivors, specifically testing whether associations are consistent across racial/ethnic groups after accounting for relevant medical and demographic factors that might explain disparities in QOL outcomes. Methods: Data were collected from a population-based cohort of non-Hispanic White ( n = 448), Black ( n = 197), and Hispanic ( n = 84) breast cancer survivors (stage 0-IIIa) in the Health, Eating, Activity, and Lifestyle Study. Physical activity was assessed ∼2.5 years after breast cancer diagnosis, with QOL assessed on average 6 to 12 months later. We used structural equation modeling to examine relationships between meeting recommended levels of physical activity and QOL, stratifying by race/ethnicity and adjusting for other demographic, comorbidity, and treatment effects. Results: Structural equation modeling indicated that meeting recommended levels of physical activity had significant positive associations with QOL for Black and non-Hispanic White women ( P < 0.05). Fewer Black women reported meeting recommended physical activity levels ( P < 0.001), but meeting recommendations was associated with better QOL. Post hoc tests showed that meeting physical activity recommendations was specifically associated with better vitality, social functioning, emotional roles, and global QOL ( P < 0.05 for all). Conclusions: These results suggest that meeting recommended levels of physical activity is associated with better QOL in non-Hispanic White and Black breast cancer survivors. Findings may help support future interventions among breast cancer survivors and promote supportive care that includes physical activity, although more research is needed to determine these relationships among Hispanic and other ethnic minority women. (Cancer Epidemiol Biomarkers Prev 2009;18(2):656–63)

Adherence to a randomized controlled trial of aerobic exercise in breast cancer survivors: the Yale exercise and survivorship study

Abstract: To examine predictors of exercise adherence in breast cancer survivors. Seventy-five breast cancer survivors were randomly assigned to exercise (n = 37) or usual care (n = 38). Demographic, prognostic, physiologic, and psychosocial information was collected at baseline and 6 months. The exercise goal was 30 min of exercise 5 days/week for 6 months. Women randomized to exercise participated in moderate-intensity recreational exercise for 123 ± 52 min/week (81% of the prescribed 150 min/week) over 6 months. Baseline variables associated with better adherence were lower body mass index (BMI), smaller waist circumference, higher amounts of physical activity 6 months prior to enrollment, being in the preparation vs. contemplation Stage of Change and higher FACT-B breast cancer subscale score. After adjusting for these variables, lower BMI and higher Stage of Change continued to be associated with better adherence (p < 0.05). Future studies of exercise and breast cancer prognosis should target obese women for participation, as well as women just beginning to contemplate participation and its benefits after a cancer diagnosis.

The Utility of Shorter Epochs in Direct Motion Monitoring

Abstract: This cross-sectional study using direct motion monitoring evaluated whether short epochs increased estimates of moderate or vigorous physical activity (MPA or VPA) and enhanced differences in daily VPA comparing overweight (OW) and nonoverweight (NOW) children. Seventy-seven children (ages 8–10 years) wore accelerometers for 7 days. We calculated two estimates (mean minutes per day) of MPA and VPA using motion counts based on a 15-s epoch and a calculated 60-s epoch produced by totaling each consecutive group of four 15-s motion counts. We compared estimates as a function of mean motion count·min-1 for sex, age, and status as OW or NOW. The results showed that a 15-s epoch produced higher estimates of VPA (mean difference of 7 min per day, p < .001). The average number of VPA minutes added using the 15-s epoch vs. the 60-s epoch was 8.8 for more active children compared with 5.8 for less active children (p < .001). There was no difference in VPA minutes between OW and NOW children. These findings suggest ...