Relation between intensity of physical activity and breast cancer risk reduction

Transportation Physical Activity Earlier in Life and Areas of the Brain related to Dementia Later in Life

INTRODUCTION

Efforts to preserve brain function may be most effective when administered before there are changes in the brain, which may occur decades before the onset of Alzheimer's disease symptoms. White matter hyperintensities (WMH), a cardiovascular disease biomarker, are areas of hyperintense signals scattered in the white matter of the brain evident on magnetic resonance images. WMH increase with age and are associated with a higher risk of dementia. The purpose of this study was to determine if there was an association between different domains and intensities of physical activity earlier in life and lower risk of dementia later in life as indicated by less WMH.

METHODS

In this cross-sectional study, face-to-face interviews were conducted with the Lifetime Total Physical Activity Questionnaire. The metabolic equivalent of task (MET) hours/week/year of moderate (3.0-5.9 METs) and vigorous-intensity (≥6 METs) occupation, transportation, household and leisure-time physical activity was obtained across school-age (6-11), adolescence (12-18), young (19-39) and middle adulthood (40-64). WMH were calculated as the percent of intracranial volume in cognitively unimpaired middle (age 40-64) and older adults (age 65+). Simultaneous multiple linear regression determined associations between moderate and vigorous-intensity occupation, transportation, household and leisure-time physical activity across school-age, adolescence, young and middle adulthood with WMH.

RESULTS

Greater moderate-intensity transportation physical activity during young (b= -.09, p=.008) and middle adulthood (b= -.14, p=.013) was associated with lower WMH in middle and older adulthood, explaining 28% (p=.003) to 29% (p=.002) of the variance in WMH (n=54).

CONCLUSIONS

Changes to the physical environment that encourage walking, running or biking, such as sidewalks and bike paths, may be strategies to mitigate the age-related increases in WMH, areas of the brain associated with higher risk of dementia.

Physical Activity and Breast Cancer: A Case-Control Study in Southern Brazil

Physical inactivity is one of the greatest public health challenges in the 21st century. More than five million deaths a year are caused by lack of physical activity (PA) around the world. Despite its relevance to public health, about one-third of the world's adults do not meet current PA recommendations for health benefits. Thus, the aim of the present study was to investigate the association between lifetime PA and risk of breast cancer. A case-control study was conducted between November 2016 and June 2017. The cases were recruited from all cancer centers in the city of Pelotas in southern Brazil. Each case was age-matched (±5 years) with a neighborhood control enrolled based on nearby addresses of the cases. Overall, 230 cases and 231 controls were included. Lifetime leisure-time PA may decrease the odds of breast cancer (adjusted OR = 0.44; 95%CI 0.23-0.86) in the comparison between the most active with the least active quartile. PA was associated with a reduction in the odds of breast cancer. Future studies should aim at understanding the physiological pathways that could explain how an active lifestyle influences this disease, helping in the establishment of volume and intensities necessary to obtain the benefits.

Lifetime Physical Activity and White Matter Hyperintensities in Cognitively Intact Adults

BACKGROUND

White matter hyperintensities (WMHs) observed on magnetic resonance images are associated with depression and increase the risk of stroke, dementia, and death. The association between physical activity and WMHs has been inconsistently reported in the literature, perhaps because studies did not account for a lifetime of physical activity or depression.

OBJECTIVES

The aim of this study was to determine the extent to which a lifetime of leisure-time physical activity is associated with less WMHs while accounting for depression.

METHODS

Face-to-face interviews were conducted with the Lifetime Total Physical Activity Questionnaire, where the metabolic equivalent of task hours per week per year was calculated. Cognitively intact participants also underwent magnetic resonance imaging, where WMHs as a percentage of intracranial volume was obtained. Hierarchical multiple linear regression was performed to compare WMHs in a more active group with a group with no psychiatric history (n = 20, mean age = 62.2 years), with a less active group with no psychiatric history (n = 13, mean age = 64.0 years), and a less active group with history of late-onset depression (n = 14, mean age = 62.8 years).

RESULTS

There was not a statistically significant difference in WMHlg10 between the more and less active groups without a psychiatric history (b = .09, p > .05) or between the more active group without a psychiatric history and the less active group with a history of depression (b = .01, p > .05). The model was predictive of WMHlg10, explaining an adjusted 15% of the variance in WMHs (p = .041).

DISCUSSION

A lifetime of leisure-time physical activity was not associated with WMHs when accounting for depression.

Up to one-third of breast cancer cases in post-menopausal Mediterranean women might be avoided by modifying lifestyle habits: the EPIC Italy study

PURPOSE

Breast cancer (BC) is the most frequent cancer among women in developed countries. Physical activity (PA), body mass index (BMI), and alcohol intake have been identified as relevant lifestyle modifiable risk factors for post-menopausal BC. We aimed to evaluate the role of these factors in modulating post-menopausal BC risk and to estimate the proportion of BC cases attributable to low PA, high BMI, and alcohol taking into account non-modifiable factors.

METHODS

In the Italian section of the EPIC study, 15,010 post-menopausal women were recruited and provided information about dietary and lifestyle habits including PA, smoking, reproductive history, and anthropometric measurements. During 14.8 years of median follow-up, 672 incident BC cases (607 invasive and 65 in situ) were identified.

RESULTS

In multivariate models, inverse associations with BC risk emerged for increasing level of total (p trend 0.02), leisure time (p trend 0.04), and occupational (p trend 0.007) PA. High BMI (HR 1.21; 95% CI 1.02-1.43 and HR 1.33; 95% CI 1.06-1.65 for overweight and obesity, respectively) and alcohol consumption higher than 10 g/day (HR 1.30; 95% CI 1.09-1.54) were associated with BC risk. We estimated that 30% (95% CI 8-50%) of post-menopausal BC cases would be avoided through an increase of leisure time PA, a BMI below 25.0, and consuming no more than one drink/day.

CONCLUSIONS

This large study carried out in Mediterranean women confirms the role of PA, BMI, and alcohol consumption in modulating post-menopausal BC risk and supports the potential benefits obtainable by modifying these lifestyle factors.

Association between Daytime Activity, Fatigue, Sleep, Anxiety, Depression, and Symptom Burden in Advanced Cancer Patients: A Preliminary Report

BACKGROUND

There is limited research in advanced cancer patients (ACP) regarding association between objectively measured daytime activity and sleep (as measured by actigraphy), patient characteristics, and cancer symptoms (fatigue, sleep, anxiety, depression, cachexia, and symptom distress scores [SDSs]).

OBJECTIVES

Our aim of the study was to determine the association between mean daytime activity (MDTA) and the following items: fatigue (FACIT-F), SDSs (Edmonton Symptom Assessment Scale [ESAS]), sleep quality (Pittsburg Sleep Quality Index [PSQI]), objective sleep variables (OSV) (sleep onset, sleep efficacy, wake after sleep onset, total sleep time), anxiety and depression (Hospital Anxiety and Depression Scale [HADS]), body composition scores, and overall survival (OS). We also examined the association between sleep [PSQI and OSV scores] and FACIT-F, HADS, and ESAS.

METHODS

Secondary analysis of a recent clinical trial of cancer-related fatigue in advanced cancer (NCT00424099). Association between MDTA and OSV (measured by actigraphy) during the first week of the study and patient characteristics, symptoms (FACIT-F, ESAS, HADS, and PSQI), and OS were analyzed.

RESULTS

Seventy-nine eligible patients were evaluable. The median age was 57 years. Median MDTA was 248.43 counts/minute. Multivariate analysis shows that low MDTA was significantly associated with age, gender, Functional Assessment of Cancer Therapy (FACT)-Functional Well-Being (FWB), ESAS dyspnea, HADS-anxiety, and total sleep time. MDTA was not associated with FACIT-F (p = 0.997) and OS (p = 0.18). Sleep quality (PSQI) was significantly associated with FACIT-F, HADS, ESAS anxiety, and depression, but none of these variables was associated with OSV.

CONCLUSION

In ACP, lower MDTA was significantly associated with age, gender, FACT-FWB, ESAS dyspnea, HADS-anxiety, and total sleep time. Both sleep quality and cancer-related fatigue scores were strongly associated with depression and anxiety. More research is needed.

Intensity of recreational physical activity in different life periods in relation to breast cancer among women in the region of Western Pomerania

Background

Recreational physical activity has been consistently associated with lower breast cancer risk, but there is a need to study the intensity and duration of activity that are critical to reduce the risk. The aim of this study was to examine the influence of moderate and vigorous intensity of recreational physical activity performed at different age periods on breast cancer risk.

Material and methods

The case-control study included 858 women with histological confirmation of invasive breast cancer and 1085 women free of any cancer diagnosis, residents of the region of Western Pomerania, aged 28–79 years. The frequency, duration and intensity of lifetime household, occupational and recreational physical activity, sociodemographic characteristics, reproductive factors, family history of breast cancer, current weight and height, and lifestyle habits were measured using a self-administered questionnaire. Unconditional logistic regression analyses were applied to estimate odds ratios (ORs) and 95% confidence intervals (CIs). The risk estimates were controlled for potential risk factors and lifetime household and occupational activities.

Results

We found a risk reduction for recreational activity done early in life (age periods 14–20, 21–34, 35–50 years), particularly at ages 14–20 and 21–34 years, regardless of intensity. Active women engaging in more than 4.5 hours per week of moderate activity during ages 14–20 years had, on average, a 36% lower risk (OR = 0.64, 95% CI: 0.45–0.89) than women who were never or rarely active. For the women who reported 4.5 hours per week of vigorous activity during this period we found about 64% risk reduction (OR = 0.36, 95% CI: 0.26–0.51). For the period after 50 years of age, recreational activity of moderate or vigorous intensity was not significantly associated with the risk.

Conclusions

Recreational physical activity of moderate or vigorous intensity done during adolescence, early and middle adulthood, particularly at ages 14–20 and 21–34 years, is associated with significantly decreased breast cancer risk.

Influence of prediagnostic recreational physical activity on survival from breast cancer

Recreational physical activity (RPA) is associated with a reduced risk of developing breast cancer, but there is limited research on whether prediagnostic RPA influences survival after breast cancer diagnosis or not. We evaluated the association between prediagnostic RPA and risk of death in 1508 women with a first breast cancer diagnosis during 1996 and 1997 in the population-based Long Island Breast Cancer Study Project. A 5-year mortality, through the end of 2002, was assessed using the National Death Index (N=196). An in-person interview was completed shortly after diagnosis to obtain information on lifetime RPA, which was expressed as metabolic equivalent task hours per week (MET-h/week). A lower risk of all-cause death was observed for women who engaged in an average of 9 or more MET-h/week of RPA from menarche to diagnosis compared with women who did not exercise [age-adjusted and BMI adjusted hazard ratio (HR)=0.57; 95% confidence interval (CI)=0.39-0.83], an association that was similar when evaluated according to menopausal status. Compared with women who did not engage in moderate RPA, those who engaged in any moderate intensity lifetime RPA (>0 MET-h/week) were found to have lower all-cause mortality (HR=0.62; 95% CI=0.46-0.84) and breast cancer-specific mortality (HR=0.64; 95% CI=0.43-0.93). Among postmenopausal women, RPA that took place after menopause resulted in a decrease in overall mortality, whereas no association was observed for RPA which took place prior to menopause (for >0 MET-h/week of RPA vs. no RPA, the HR=0.61; 95% CI=0.39-0.94 and HR=1.00; 95% CI=0.65-1.54, respectively). This study provides support that RPA prior to breast cancer diagnosis improves survival.

A systematic review of the evidence for Canada's Physical Activity Guidelines for Adults

This systematic review examines critically the scientific basis for Canada's Physical Activity Guide for Healthy Active Living for adults. Particular reference is given to the dose-response relationship between physical activity and premature all-cause mortality and seven chronic diseases (cardiovascular disease, stroke, hypertension, colon cancer, breast cancer, type 2 diabetes (diabetes mellitus) and osteoporosis). The strength of the relationship between physical activity and specific health outcomes is evaluated critically. Literature was obtained through searching electronic databases (e.g., MEDLINE, EMBASE), cross-referencing, and through the authors' knowledge of the area. For inclusion in our systematic review articles must have at least 3 levels of physical activity and the concomitant risk for each chronic disease. The quality of included studies was appraised using a modified Downs and Black tool. Through this search we identified a total of 254 articles that met the eligibility criteria related to premature all-cause mortality (N = 70), cardiovascular disease (N = 49), stroke (N = 25), hypertension (N = 12), colon cancer (N = 33), breast cancer (N = 43), type 2 diabetes (N = 20), and osteoporosis (N = 2). Overall, the current literature supports clearly the dose-response relationship between physical activity and the seven chronic conditions identified. Moreover, higher levels of physical activity reduce the risk for premature all-cause mortality. The current Canadian guidelines appear to be appropriate to reduce the risk for the seven chronic conditions identified above and all-cause mortality.

Case-control study of lifetime total physical activity and endometrial cancer risk

A population-based case–control study of physical activity and endometrial cancer risk was conducted in Alberta between 2002 and 2006. Incident, histologically confirmed cases of endometrial cancer (n = 542) were frequency age-matched to controls (n = 1,032). The Lifetime Total Physical Activity Questionnaire was used to measure occupational, household, and recreational activity levels. Multivariable logistic regression analyses were conducted. Total lifetime physical activity reduced endometrial cancer risk (odds ratio [OR] for >129 vs. <82 MET-h/week/year = 0.86, 95% confidence interval [95% CI]: 0.63, 1.18). By type of activity, the risks were significantly decreased for greater recreational activity (OR = 0.64, 95% CI: 0.47, 0.87), but not for household activity (OR = 1.09, 95% CI: 0.75, 1.58) and/or occupational activity (OR = 0.90, 95% CI: 0.67, 1.20) when comparing the highest to lowest quartiles. For activity performed at different biologically defined life periods, some indication of reduced risks with activity done between menarche and full-term pregnancy and after menarche was observed. When examining the activity by intensity of activity (i.e., light <3, moderate 3–6, and vigorous >6 METs), light activity slightly decreased endometrial cancer risk (OR = 0.68, 95% CI: 0.48, 0.97) but no association with moderate or vigorous intensity activity was found. Endometrial cancer risk was increased with sedentary occupational activity by 28% (95 CI%: 0.89, 1.83) for >11.3 h/week/year versus ≤2.4 h/week/year or by 11% for every 5 h/week/year spent in sedentary behavior. This study provides evidence for a decreased risk between lifetime physical activity and endometrial cancer risk and a possible increased risk associated with sedentary behavior.

Intensity and timing of physical activity in relation to postmenopausal breast cancer risk: the prospective NIH-AARP diet and health study

BACKGROUND

Despite strong evidence of an inverse association of physical activity with postmenopausal breast cancer risk, whether a certain intensity or time of life of physical activity is most effective for lowering breast cancer risk is not known.

METHODS

In 118,899 postmenopausal women in the prospective NIH-AARP Diet and Health Study, we examined the relations of light and moderate-to-vigorous intensity physical activity during four periods of life ("historical": ages 15-18, 19-29, 35-39 years; "recent": past 10 years) to postmenopausal breast cancer risk. Physical activity was assessed by self-report at baseline, and 4287 incident breast cancers were identified over 6.6 years of follow-up.

RESULTS

In age-adjusted and multivariate Cox regression models, >7 hours/week of moderate-to-vigorous activity during the past 10 years was associated with 16% reduced risk of postmenopausal breast cancer (RR:0.84; 95%CI:0.76,0.93) compared with inactivity. The association remained statistically significant after adjustment for BMI (RR:0.87; 95%CI:0.78,0.96). Neither moderate-to-vigorous activity during other periods of life nor light intensity activity during any period of life was related to breast cancer risk, and associations did not vary by tumor characteristics.

CONCLUSION

A high level of recent, but not historical, physical activity of moderate-to-vigorous intensity is associated with reduced postmenopausal breast cancer risk. More precise recall of recent physical activity than activity in the distant past is one possible explanation for our findings.

Effects of a yoga program on cortisol rhythm and mood states in early breast cancer patients undergoing adjuvant radiotherapy: a randomized controlled trial

Objectives. This study compares the effects of an integrated yoga program with brief supportive therapy in breast cancer outpatients undergoing adjuvant radiotherapy at a cancer center.

METHODS

Eighty-eight stage II and III breast cancer outpatients are randomly assigned to receive yoga (n = 44) or brief supportive therapy (n = 44) prior to radiotherapy treatment. Assessments include diurnal salivary cortisol levels 3 days before and after radiotherapy and self-ratings of anxiety, depression, and stress collected before and after 6 weeks of radiotherapy.

RESULTS

Analysis of covariance reveals significant decreases in anxiety (P < .001), depression (P = .002), perceived stress (P < .001), 6 a.m. salivary cortisol (P = .009), and pooled mean cortisol (P = .03) in the yoga group compared with controls. There is a significant positive correlation between morning salivary cortisol level and anxiety and depression.

CONCLUSION

Yoga might have a role in managing self-reported psychological distress and modulating circadian patterns of stress hormones in early breast cancer patients undergoing adjuvant radiotherapy.

Effects of aerobic exercise on uric acid, total antioxidant activity, oxidative stress, and nitric oxide in human saliva

The aim of this study was to determine the effect of aerobic exercise on uric acid (UA), total antioxidant activity (TAA), lipid hydroperoxides, and nitric oxide (NO) metabolites in human saliva. Twenty-four healthy male and female subjects were studied during a 10,000-m race. Saliva samples were collected 1 h before and immediately after exercise. The NO concentration was determined by the Griess reaction, UA by enzymatic method, TAA by the ABTS method, and lipid hydroperoxide by the ferrous iron/xylenol orange (FOX) method. A repeated measures ANOVA was used to examine the effect of aerobic exercise on salivary UA, TAA, lipid hydroperoxides, and NO metabolites. Aerobic exercise caused an increase in both salivary UA and TAA, and a decrease in salivary lipid hydroperoxide. There was no, however, change in nitrite concentration. These results suggested that aerobic exercise-induced increment in both UA and TAA seems to inhibit lipid hydroperoxide generation, a marker of oxidative stress in human saliva.

Information Needs of Women At Risk of Breast Cancer

Purpose: Information needs and current information sources related to healthy eating, active living, and healthy body weight were examined in women attending breast cancer risk assessment clinics.

Methods: Convenience sampling was used to recruit 257 women over 20 years old. The women completed a selfadministered survey (52.8% response rate) containing both closed- and open-ended questions. Most respondents were 49 or younger, were English-speaking, reported annual family incomes over $140,000, and resided in urban communities.

Results: Participants reported a need for general information concerning healthy eating, active living, and healthy body weight. For example, they wanted information on reading food labels (51.0%), healthy recipes (51.0%), activities for increasing overall fitness (52.5%), and achieving healthy body weights (48.6%). They also wanted information concerning the relationships between cancer risk and specific foods and nutrients, such as antioxidants (65.0%), supplements (60.7%), phytochemicals (47.5%), and omega-3 fatty acids (45.5%). Participants most often turned to magazines, friends, and family members when they wanted information on healthy eating, active living, and healthy body weight.

Conclusions: These findings present an opportunity for dietitians to enhance their leadership role in creating and disseminating evidence-based information to meet the expressed needs of women who may be at increased risk for breast cancer.

Exercise for health and wellness at midlife and beyond: balancing benefits and risks

As noted in research on frailty in women, regular exercise can limit age-related functional decline. However, physical activity has been implicated in the etiology of such musculoskeletal disorders as osteoarthritis. Proper exercise plans must strike a balance between promoting health and limiting the risk of injury. This article discusses age-related musculoskeletal changes and gender-specific conditions that may predispose midlife and older women to musculoskeletal injuries. The controversy about how physical activity may relate to osteoarthritis is discussed, along with common osteoarthritic-related spinal and appendicular conditions. Exercise prescription for women is briefly presented. The consistent message in the literature is that exercise is a safe and powerful tool to prevent and treat many medical, psychological, and musculoskeletal conditions in females at midlife and beyond.

Effect of Energy Deficiency on Estrogen Metabolism in Premenopausal Women

PURPOSE

Physical activity has been associated with decreased breast cancer risk, potentially through changes in estrogen metabolism. Two-hydroxyestrone (2-OHE1) and 16alpha-hydroxyestrone (16alpha-OHE1) have different biological properties, and the ratio of these metabolites (2/16) has been proposed to predict breast cancer risk. Diet and exercise have been found to influence estrogen metabolism, particularly when a state of negative energy balance is achieved. We sought to determine whether 4 months of moderate-intensity exercise coupled with calorie restriction would result in changes in urinary 2-OHE1, 16alpha-OHE1, or 2/16 in sedentary, premenopausal, eumenorrheic women.

METHODS

Average age was 31.5 yr, average body fat was 31.6%, and average BMI was 23.7. Urinary estrogen metabolites were measured in 24 women during the baseline and for four intervention months in the midfollicular and midluteal phases.

RESULTS

The intervention produced a significant drop in body fat (4.5%) and body weight (3.7 kg). Aerobic fitness increased significantly (26%; P < 0.001). Overall, there were no significant effects of the diet and exercise intervention on 2-OHE1, 16alpha-OHE1, or 2/16. However, when divided into tertiles according to baseline 2/16, the intervention resulted in significant increases in 2/16 in women in the lowest tertile. Women in the lowest tertile (average 2/16 = 0.91) did not differ from the other tertiles in baseline estradiol concentrations, body fat, weight, fitness, or changes in these variables with the intervention.

CONCLUSION

The data suggest that women at higher risk for developing breast cancer because of low 2/16 may reduce their risk by participating in lifestyle interventions such as exercise/calorie restriction.

Lifetime recreational and occupational physical activity and risk of in situ and invasive breast cancer

Numerous studies have observed reduced breast cancer risk with increasing levels of physical activity, yet these findings have been inconsistent about optimal times of activity and effect modification by other factors. We investigated the association between recreational and occupational physical activity and breast cancer risk in a population-based case-control study in Massachusetts, New Hampshire, and Wisconsin. During structured telephone interviews, 7,630 controls, 1,689 in situ, and 6,391 invasive breast cancer cases, ages 20 to 69 years, reported lifetime history of recreational physical activity and occupation. Neither lifetime recreational nor strenuous occupational physical activity appeared to be associated with risk of breast carcinoma in situ. In contrast, recreational physical activity was associated with a reduced risk of invasive breast cancer. After adjustment for potentially confounding factors, women averaging >6 h per week of strenuous recreational activity over their lifetime had a 23% reduction in the odds ratio of invasive breast cancer when compared with women reporting no recreational activity (95% confidence interval, 0.65-0.92; P(trend) = 0.05). However, this reduction in risk was limited to women without a first-degree family history of breast cancer (P(interaction) = 0.02). Inverse associations were observed for physical activity early in life, in the postmenopausal years, and in the recent past, but these findings were confined to women without a family history of breast cancer. Lifetime strenuous occupational activity was not associated with invasive breast cancer risk. These results provide further evidence that, for most women, physical activity may reduce the risk of invasive breast cancer.

Physical Activity and Breast Cancer

BACKGROUND

Many epidemiologic studies have found an association between physical activity and breast cancer risk, although this has not been a consistent finding.

METHODS

Studies were identified through a systematic review of literature available on PubMed through February 2006. We included all cohort and case-control studies that assessed total or leisure time activities in relation to occurrence or mortality of breast cancer. The fully adjusted risk estimates and 95% confidence intervals for the highest versus lowest level of activity were documented for each study as well as evidence for a dose-response relationship. Methodologic quality was also assessed. Due to statistical and methodologic heterogeneity among studies, we did not carry out statistical pooling. To draw conclusions, we performed a best-evidence synthesis taking study quality into account.

RESULTS

Nineteen cohort studies and 29 case-control studies were evaluated. There was strong evidence for an inverse association between physical activity and postmenopausal breast cancer with risk reductions ranging from 20% to 80%. For premenopausal breast cancer, however, the evidence was much weaker. For pre- and postmenopausal breast cancer combined, physical activity was associated with a modest (15-20%) decreased risk. Evidence for a dose-response relationship was observed in approximately half of the higher-quality studies that reported a decreased risk. A trend analysis indicated a 6% (95% confidence interval = 3% to 8%) decrease in breast cancer risk for each additional hour of physical activity per week assuming that the level of activity would be sustained.

CONCLUSIONS

There is evidence for an inverse association between physical activity and breast cancer risk. The evidence is stronger for postmenopausal breast cancer than for premenopausal breast cancer.

Physical Activity and Breast Cancer Risk: The European Prospective Investigation into Cancer and Nutrition

There is convincing evidence for a decreased risk of breast cancer with increased physical activity. Uncertainties remain, however, about the role of different types of physical activity on breast cancer risk and the potential effect modification for these associations. We used data from 218,169 premenopausal and postmenopausal women from nine European countries, ages 20 to 80 years at study entry into the European Prospective Investigation into Cancer and Nutrition. Hazard ratios (HR) from multivariate Cox regression models were calculated using metabolic equivalent value-based physical activity variables categorized in quartiles, adjusted for age, study center, education, body mass index, smoking, alcohol use, age at menarche, age at first pregnancy, parity, current oral contraceptive use, and hormone replacement therapy use. The physical activity assessment included recreational, household, and occupational activities. A total physical activity index was estimated based on cross-tabulation of these separate types of activity. During 6.4 years of follow-up, 3,423 incident invasive breast cancers were identified. Overall, increasing total physical activity was associated with a reduction in breast cancer risk among postmenopausal women (P(trend) = 0.06). Specifically, household activity was associated with a significantly reduced risk in postmenopausal (HR, 0.81; 95% confidence interval, 0.70-0.93, highest versus the lowest quartile; P(trend) = 0.001) and premenopausal (HR, 0.71; 95% confidence interval, 0.55-0.90, highest versus lowest quartile; P(trend) = 0.003) women. Occupational activity and recreational activity were not significantly related to breast cancer risk in both premenopausal and postmenopausal women. This study provides additional evidence for a protective effect of physical activity on breast cancer risk.

Reliability and validity of the Past Year Total Physical Activity Questionnaire

The authors determined the validity and reliability of their Past Year Total Physical Activity Questionnaire (PYTPAQ), which assesses the frequency, duration, and intensity of occupational, household, and recreational activities performed over the past year. The PYTPAQ was completed twice at baseline, 9 weeks apart (on average), by 154 healthy Canadian men and women aged 35-65 years for assessment of reliability. The PYTPAQ was completed again 1 year later as a self-administered questionnaire. Four times during the year, participants wore an accelerometer for 7 days and completed 7-day physical activity logs. The authors assessed validity by comparing PYTPAQ summary values with 1-year averages of the physical activity logs and accelerometer data and with physical fitness and anthropometric data measured at baseline and 1 year. Spearman correlations for reliability (metabolic equivalent-hours/week) were 0.64 for total activity, 0.70 for occupational activity, 0.73 for recreational activity, and 0.65 for household activity. For total activity, the intraclass correlation coefficient for correlation between the PYTPAQ and the 7-day physical activity logs was 0.42 (95% confidence interval: 0.28, 0.54), and for the accelerometer data it was 0.18 (95% confidence interval: 0.03, 0.32). Spearman correlations between PYTPAQ hours/week of vigorous activity and maximal oxygen uptake were 0.37 and 0.32 at baseline and follow-up, respectively. In general, the PYTPAQ has acceptable reliability and validity for measurement of past-year physical activity that is comparable to that of similar questionnaires.

Effect of Physical Activity on Women at Increased Risk of Breast Cancer: Results from the E3N Cohort Study

PURPOSE

There is a need to investigate the type, duration, frequency, and intensity of physical activity that are critical to reduce the risk of breast cancer, and if this relation differs among subgroups of women.

METHODS

We analyzed the relation between physical activity and breast cancer incidence between 1990 and 2002 (n=3,424 cases), among 90,509 women of the French E3N cohort, ages between 40 and 65 years in 1990. We gave special attention to effect modification by body mass index (BMI), family history of breast cancer, parity, and hormone replacement therapy (HRT).

RESULTS

A linear decrease in risk of breast cancer was observed with increasing amounts of moderate (P(trend)<0.01) and vigorous (P(trend)<0.0001) recreational activities. Compared with women who reported no recreational activities, those with more than five weekly hours of vigorous recreational activity had a relative risk of 0.62 (0.49-0.78). This decrease was still observed among women who were overweight, nulliparous, had a family history of breast cancer, or used HRT. Compared with the whole cohort, among nulliparous women, the reduction of risk observed was of a higher magnitude, although the test for heterogeneity did not reach statistical significance.

CONCLUSION

A risk reduction of breast cancer was particularly observed with vigorous recreational activity. Further investigations are needed to confirm that intensity is an important variable to consider in risk reduction and to identify the precise biological mechanisms involved in such a risk reduction.

Mindfulness-based stress reduction in relation to quality of life, mood, symptoms of stress and levels of cortisol, dehydroepiandrosterone sulfate (DHEAS) and melatonin in breast and prostate cancer outpatients

OBJECTIVES

This study investigated the relationships between a mindfulness-based stress reduction meditation program for early stage breast and prostate cancer patients and quality of life, mood states, stress symptoms, and levels of cortisol, dehydroepiandrosterone-sulfate (DHEAS) and melatonin.

METHODS

Fifty-nine patients with breast cancer and 10 with prostate cancer enrolled in an eight-week Mindfulness-Based Stress Reduction (MBSR) program that incorporated relaxation, meditation, gentle yoga, and daily home practice. Demographic and health behavior variables, quality of life, mood, stress, and the hormone measures of salivary cortisol (assessed three times/day), plasma DHEAS, and salivary melatonin were assessed pre- and post-intervention.

RESULTS

Fifty-eight and 42 patients were assessed pre- and post-intervention, respectively. Significant improvements were seen in overall quality of life, symptoms of stress, and sleep quality, but these improvements were not significantly correlated with the degree of program attendance or minutes of home practice. No significant improvements were seen in mood disturbance. Improvements in quality of life were associated with decreases in afternoon cortisol levels, but not with morning or evening levels. Changes in stress symptoms or mood were not related to changes in hormone levels. Approximately 40% of the sample demonstrated abnormal cortisol secretion patterns both pre- and post-intervention, but within that group patterns shifted from "inverted-V-shaped" patterns towards more "V-shaped" patterns of secretion. No overall changes in DHEAS or melatonin were found, but nonsignificant shifts in DHEAS patterns were consistent with healthier profiles for both men and women.

CONCLUSIONS

MBSR program enrollment was associated with enhanced quality of life and decreased stress symptoms in breast and prostate cancer patients, and resulted in possibly beneficial changes in hypothalamic-pituitary-adrenal (HPA) axis functioning. These pilot data represent a preliminary investigation of the relationships between MBSR program participation and hormone levels, highlighting the need for better-controlled studies in this area.

Mindfulness-based stress reduction in relation to quality of life, mood, symptoms of stress, and immune parameters in breast and prostate cancer outpatients

OBJECTIVES

This study investigated the relationships between a mindfulness-based stress reduction meditation program for early stage breast and prostate cancer patients and quality of life, mood states, stress symptoms, lymphocyte counts, and cytokine production.

METHODS

Forty-nine patients with breast cancer and 10 with prostate cancer participated in an 8-week MBSR program that incorporated relaxation, meditation, gentle yoga, and daily home practice. Demographic and health behavior variables, quality of life (EORTC QLQ C-30), mood (POMS), stress (SOSI), and counts of NK, NKT, B, T total, T helper, and T cytotoxic cells, as well as NK and T cell production of TNF, IFN-gamma, IL-4, and IL-10 were assessed pre- and postintervention.

RESULTS

Fifty-nine and 42 patients were assessed pre- and postintervention, respectively. Significant improvements were seen in overall quality of life, symptoms of stress, and sleep quality. Although there were no significant changes in the overall number of lymphocytes or cell subsets, T cell production of IL-4 increased and IFN-gamma decreased, whereas NK cell production of IL-10 decreased. These results are consistent with a shift in immune profile from one associated with depressive symptoms to a more normal profile.

CONCLUSIONS

MBSR participation was associated with enhanced quality of life and decreased stress symptoms in breast and prostate cancer patients. This study is also the first to show changes in cancer-related cytokine production associated with program participation.

Physical activity and breast cancer risk among Asian-American women in Los Angeles: a case-control study

BACKGROUND

To the authors' knowledge, there have been few studies published to date regarding physical activity patterns and breast cancer risk in Asian and Asian-American women.

METHODS

The authors conducted a population-based case-control study of 501 Asian-American women with incident breast cancer and a control group of 594 Asian-American women in Los Angeles County to evaluate the role of lifetime physical activity on breast cancer risk. Information concerning lifetime recreational physical activity (i.e., type of activity, duration [years], and frequency [average hours per week]) and occupational physical activity was obtained using a structured questionnaire that was administered in person.

RESULTS

Increasing years and levels (average metabolic equivalent [MET] hours per week) of lifetime recreational activity were associated with a significantly reduced risk of breast cancer after adjusting for demographic factors, migration history, and menstrual and reproductive factors. Compared with women who had no lifetime recreational physical activity, <or= 3 MET hours per week, > 3-6 MET hours per week, > 6-12 MET hours per week, and > 12 MET hours per week of activity were associated with significantly reduced risk, with odds ratios (and 95% confidence intervals) of 0.91 (0.55-1.49), 0.65 (0.39-1.10), 0.53 (0.31-0.90), and 0.47 (0.28-0.80), respectively (P value for trend < 0.001). The risk of breast cancer was associated inversely with occupational physical activity, although the result was not statistically significant.

CONCLUSIONS

The findings of the current study provide further support for the finding that physical activity has a protective role in breast cancer.

Exercise, cachexia, and cancer therapy: a molecular rationale

Evidence from recent publications indicates that repeated exercise may enhance the quality of life of cancer patients. The lack of reported negative effects and the consistency of the observed benefits lead one to conclude that physical exercise may provide a low-risk therapy that can improve patients' capacity to perform activities of daily living and improve their quality of life. Repeated physical activity may attenuate the adverse effects of cancer therapy, prevent or reverse cachexia, and reduce risk for a second cancer through suppression of inflammatory responses or enhancement of insulin sensitivity, rates of protein synthesis, and anti-oxidant and phase II enzyme activities. These results most likely come about through the ability of physical exercise to attenuate a chronic inflammatory signaling process and to transiently activate the mitogen-activated protein kinase, c-Jun NH2-terminal kinase, c-Jun NH2-terminal kinase-mitogen-activated protein kinase, and nuclear factor-kappa B pathways and through its ability to enhance insulin sensitivity. Expanded molecular-based research into these areas may provide new insights into the biological mechanisms associated with cancer rehabilitation and endogenous risk.

Lifetime physical activity and breast cancer risk in pre- and postmenopausal women

PURPOSE

This research examined associations between leisure time and occupational physical activity (PA) across the lifespan and pre- and postmenopausal breast cancer.

METHODS

In a population-based case-control study, 301 premenopausal cases, 316 premenopausal controls, 439 postmenopausal cases, and 494 postmenopausal controls, 40- to 85-yr-old reported time spent in exercise or sports strenuous enough to sweat and miles walked per week for time periods 2, 10, and 20 yr before the interview and at age 16. Lifetime occupational history was obtained. Jobs were coded according to the National Cancer Institute's PA job matrix.

RESULTS

Strenuous PA was generally associated with a reduced breast cancer risk. Among women categorized as active at all four periods [at least 91+ h.yr(-1) (1.75+ h.wk(-1) avg)], a strong, significant protective effect was observed in postmenopausal [odds ratio (OR) 0.50 (0.28-0.90)] but not in premenopausal women [OR 1.06 (0.54-2.08)]. A strong protective effect was observed for activity performed 20 yr prior, in both pre- and postmenopausal women, although CIs overlapped for different time periods. Using women who reported no strenuous activity as the referent, OR (95% CIs) for the highest PA category [182+ h.yr(-1) (3.5 h.wk(-1) avg)] 20 yr ago were 0.57(0.31-1.05) and 0.51(0.31-0.83) for pre- and postmenopausal women, respectively. Walking was generally unrelated to risk. There was some indication of increased risk for the upper category of occupational PA for postmenopausal women, perhaps related to other industrial occupational exposures.

CONCLUSION

Our results suggest a modest protective effect of strenuous leisure time PA on breast cancer risk in both pre- and postmenopausal women. The effects appear strongest for those active at least 20 yr prior and among postmenopausal women who were consistently active throughout their lifetime.

Case-control study of anthropometric measures and breast cancer risk

A population-based case-control study of 1,233 incident breast cancer cases and 1,241 controls was conducted in Alberta between 1995 and 1997 to examine the influence of anthropometric factors on the risk of breast cancer using several newly derived variables. Data on current height, weight and waist and hip circumference were collected by interviewers using standardized methods. Respondents recalled their body weight at each decade from age 20 to the referent year. Several variables were estimated, and unconditional logistic regression was used to estimate odds ratios (ORs) and 95% confidence intervals (95% CIs). No statistically significant associations for any of the estimated variables with breast cancer risk for premenopausal women (462 cases, 475 controls) were found. The results for postmenopausal women (771 cases, 762 controls) in the highest vs. lowest quartiles were, for waist circumference, OR = 1.30 (95% CI 0.97-1.73); waist-hip ratio, OR = 1.43 (95% CI 1.07-1.93); weight gain since age 20, OR = 1.35 (05% CI 1.01-1.81); difference between maximum and minimum weights over adult lifetime, OR = 1.56 (95% CI 1.16-2.08); and the reference weight minus the minimum weight since age 20, OR = 1.47 (95% CI 1.10-1.97). Statistically significant trends in risk were observed for these variables. Effect modification with hormone replacement therapy use was found for most variables assessed for postmenopausal women, with much stronger associations found among never-users compared to ever-users. We found strong evidence that waist-hip ratio and weight gained over lifetime, as assessed by different variables, are postmenopausal breast cancer risk factors. These effects were independent of dietary intake and lifetime total physical activity.