Physical activity and cancer: lessons learned from nutritional epidemiology

Cardio-oncology Related to Heart Failure: Common Risk Factors Between Cancer and Cardiovascular Disease

There is a growing body of evidence that suggests cancer and cardiovascular disease have a shared biological mechanism. Although there are several shared risk factors for both diseases, including advancing age, gender, obesity, diabetes, physical activity, tobacco use, and diet, inflammation and biomarkers, such as insulinlike growth factor 1, leptin, estrogen, and adiponectin, may also play a role in the biology of these diseases. This article provides an overview of the shared biological mechanism between cancer and cardiovascular disease.

The effect of motivational interviewing-based intervention using self-determination theory on promotion of physical activity among women in reproductive age: A randomized clinical trial

Background

Physical activity (PA) prevents chronic diseases. Self-determination theory (SDT) provides a useful framework to understand the nature of motivational interviewing (MI).

Objective

This study aimed to determine the effect of MI-based intervention using SDT on the promotion of PA among women in reproductive age.

Methods

Seventy women in reproductive age were selected by clustering sampling method for this randomized controlled trial. The questionnaire included the variables of physical fitness test, SDT, and global physical activity questionnaire (GPAQ). The validity of the questionnaires was approved using content validity ratio (CVR) and index (CVI). The reliability and internal consistency of the questionnaires and measures was approved using test-retest method and Cronbach’s alpha test, respectively. The intervention group (n=35) received four MI sessions through theory and one standard education session about PA. The control group (n=35) received a standard education session about PA.

Results

Four months after the intervention, an increase in the mean scores of total PA (p<0.001, ES=4.77), physical fitness tests including flexibility (p<0.001, ES=1.59), muscular endurance (p<0.001, ES=2.0), cardiorespiratory endurance (p<0.001, ES=0.51), and a decrease in mean scores of agility test (p<0.001, ES= − 0.51) and sedentary behavior (p<0.01, ES=− 0.74) was observed in the intervention group compared to the control group. The intervention group reported an increase in the scores of intrinsic motivation (p<0.001, ES=3.34), identified regulation (p<0.001, ES= 1.28), perceptions of competence (p<0.001, ES=0.81) and autonomy (p<0.001, ES=2.01), enjoyment (p<0.001, ES=0.98) and health motives (p<0.01, ES=0.19), health care climate (p<0.001, ES=4.6), and a decreased score of external regulation (p<0.01, ES=−0.55) and amotivation (p<0.01, ES= −0.56) over time, compared to the control group.

Conclusion

MI-based intervention using SDT was effective on the promotion of PA.

Trial registration

The Trial was registered at the Iranian Registry of Clinical Trial (http://www.irct.ir) with the Irct ID: IRCT2015101924592N1.

Physical activity in leisure-time and risk of cancer: 14-year follow-up of 28,000 Danish men and women

Aim: The preventive effect of physical activity on risk of cancer in general remains controversial. This study aimed at assessment of the associations between leisure- time physical activity and incidence of cancer in the general population of adult men and women. Methods: 13,216 women and 18,718 men aged 20—93 years selected from the general population participated in a health examination including a questionnaire with information on physical activity, smoking, alcohol intake, postmenopausal hormones, and socioeconomic status. Incident cases of cancers where recorded during a follow-up period of 14 years. The six most frequent cancer cases in both sexes were included in this analysis. Results: A highly significant inverse association was seen between vigorous physical activity in leisure time and cancer of the ovary, adjusted rate ratio being 0.33 (95% CI 0.16—0.67; p=0.001) for the most physical active women. In men there was a highly significant increase for non-melanoma skin cancer, with adjusted rate ratio of 1.72 (95% CI 1.23—2.40; p=0.001), for the most active men and vigorous activity was associated with a non-significant lower risk of colon cancer, the adjusted rate ratio being 0.72 (95% CI 0.47—1.11; p=0.06). Conclusion: Generally, there were no, or only weakly, inverse associations between physical activity in leisure time and incidence of cancer, except for cancer of the ovary.

Active commuting to elementary school and adiposity: an observational study

BACKGROUND

Active commuting to school (ACS; walking or cycling to school) appears promising for decreasing children's obesity risk, although long-term studies are sparse. The aim was to examine whether kindergarten ACS was associated with fifth-grade adiposity.

METHODS

This study was a secondary analysis of the Early Childhood Longitudinal Study, Kindergarten (n=7938). Enrollment in kindergarten (1998-1999) was nationally representative of the United States and follow-up occurred in 2004. Kindergarten ACS was the main exposure variable and fifth-grade BMI z-score was the main outcome measure. Covariates included (1) neighborhood safety and BMI z-score in kindergarten and (2) demographics (i.e., age, gender, race/ethnicity, socioeconomic status, single- vs. two-parent households, region of country, and urbanicity in fifth grade). Three interactions were included: school travel*neighborhood safety; school travel*BMI z-score (kindergarten); and school travel*socioeconomic status. Analysis of covariance accounted for the complex sampling design.

RESULTS

Kindergarten ACS was associated with lower BMI z-score in fifth grade. The interaction of school travel*neighborhood safety indicated that children from less-safe neighborhoods who did ACS in kindergarten had a lower fifth-grade BMI z-score (p<0.05) than their peers who did not do ACS in kindergarten (i.e., in terms of BMI, this difference was -0.49 kg/m(2) for children of average height in less-safe neighborhoods).

CONCLUSION

Among children from less-safe neighborhoods, kindergarten ACS independently predicted lower BMI z-score in fifth grade among a national US cohort. Interventions and policies to increase ACS among young children, especially from unsafe neighborhoods, are warranted and should address parents' safety concerns.

Association of overweight and obesity with breast cancer in India

Background:

In women, cancer of the breast is one of the most common incident cancer and cause of death from cancer. Anthropometric factors of weight, height, and body mass index (BMI) have been associated with breast cancer risk.

Objectives:

To study the association of overweight and obesity with breast cancer in India.

Materials and Methods:

A hospital-based matched case-control study was conducted. Three hundred and twenty newly diagnosed breast cancer patients and three hundred and twenty normal healthy individuals constituted the study population. The subjects in the control group were matched individually with the patients for their age ±2 years and socioeconomic status. Anthropometric measurements of weight and height were recorded utilizing the standard equipments and methodology. The paired ‘t’ test and univariate logistic regression analysis were carried out.

Results:

It was observed that the patients had a statistically higher mean weight, body mass index, and mid upper arm circumference as compared to the controls. It was observed that the risk of breast cancer increased with increasing levels of BMI. Overweight and obese women had Odd's redio of 1.06 and 2.27, respectively, as compared to women with normal weight.

Conclusions:

The results of the present study revealed a strong association of overweight and obesity with breast cancer in the Indian population.

Obesity augmented breast cancer risk: a potential risk factor for Indian women

BACKGROUND

Obesity is caused by disturbances of energy balance, which is homeostasized by the physiological processes. The study aims to determine the possible impact of rising prevalence of obesity and its effect in the development of breast carcinoma (BC) in Indian population.

METHODS

This study is carried out on patients (N = 358) who were diagnosed with BC and breast diseases (BD) by calculating their BMI admitted during the period of 2005 to 2009. NIH criteria were used to categorize the patients. Pathological factors of BC patient were then compared among groups.

RESULT

These results were indicative of significant positive association between BC risks with peri/post menopausal status, residence, diet nature, and tobacco uses. Metastases were identified more commonly with increasing weight. It was found to be independently associated with obesity I (OR = 3.103, 95% CI = 1.633-5.895) and obesity II (OR = 6.803, 95% CI = 2.415-19.162). Disease stage and cancer related mortality were significantly associated with increased BMI.

CONCLUSION

The higher prevalence of severe obesity among Indian population was associated with BC. The only alteration apart from early diagnosis is opting for a more natural lifestyle that will affect energy equilibrium and prove to be a viable option for prevention in carcinoma of breast for better survival.

A multicomponent model of the theory of planned behaviour

The purpose of this study was to investigate the measurement and predictive structure of multiple components of attitude (affective and instrumental), subjective norm (injunctive and descriptive) and an alternative measure of perceived behavioural control (PBC; skills/ability, opportunity, and resources) in the exercise domain. An additional purpose of the study was to compare the validity of the alternative PBC measure to a standard PBC measure for predicting exercise intention and behaviour. Participants were 220 undergraduates who completed measures of the theory of planned behaviour (TPB) and a 2-week follow-up of exercise behaviour. Results supported the discriminant validity in the measurement domains of all TPB components. Predictive validity of exercise behaviour for these components, however, was only evident for attitude and PBC components. Our alternative PBC measure was found commensurate with the standard PBC measure. Finally, intention significantly (p < .05) predicted exercise behaviour (R2 = .42), while affective attitude, and perceived opportunity significantly (p < .05) predicted intention (R2 = .47).

Exercise prescription for Iranian midlife women

Objectives:

The purpose of this study is to determine the effect of a multimodal intervention (including the Women’s Wellness Program) on increasing levels of physical activity in Iranian midlife women.

Study design:

This 12-week study was conducted in women aged 50–65 years living in the general population. Women who were allocated to the intervention group (n = 40) received an intervention, which combined a multimodal program of physical activity and health education. Women in the control group continued their normal physical activities (n = 45).

Mean outcome measure:

The women completed a questionnaire that included measures for items of interest for this analysis, such as menopausal status, sociodemographic, and exercise and activity levels.

Results:

Analysis of covariance indicated that the intervention was effective in improving women’s physical activity. The test showed that there was a significant difference between intervention and control in current vigorous activity.

Conclusion:

Physical activity should be encouraged for prevention and reduction of risks for chronic disease and for improvement of health in midlife women. The multimodal intervention program may offer implications for designing and implementing exercise interventions in further studies.

Older adults' perceived physical activity enablers and barriers: a multicultural perspective

This study identified perceived physical activity (PA) enablers and barriers among a racially/ethnically and geographically diverse group of older adults. Data were from 42 focus groups conducted with African Americans, American Indians, Latinos, Chinese, Vietnamese, and non-Hispanic Whites (hereafter Whites). Constant-comparison methods were used to analyze the data. Common barriers were health problems, fear of falling, and inconvenience. Common enablers were positive outcome expectations, social support, and PA program access. American Indians mentioned the built environment and lack of knowledge about PA as barriers and health benefits as an enabler more than participants in other groups. Whites and American Indians emphasized the importance of PA programs specifically designed for older adults. Findings suggest several ways to promote PA among older people, including developing exercise programs designed for older adults and health messages promoting existing places and programs older adults can use to engage in PA.

The role of body weight in the relationship between physical activity and endometrial cancer: results from a large cohort of US women

Factors influencing circulating estrogen levels, insulin-mediated pathways or energy balance through obesity-related mechanisms, such as physical activity, have been proposed as potential risk factors for endometrial cancer. We examined measures of physical activity in relation to endometrial cancer risk in the American Cancer Society Cancer Prevention Study II Nutrition Cohort, a prospective study of cancer incidence and mortality, using information obtained at baseline in 1992. From 1992 to 2003, 466 incident endometrial cancers were identified among 42,672 postmenopausal women with intact uteri who were cancer-free at enrollment. Cox proportional hazards modeling was used to compute hazard rate ratios (RR) while adjusting for potential confounders. To assess the role of body mass index (BMI) in this relationship, we computed multivariate RR with and without adjustment for BMI and stratifying by BMI. All measures of physical activity and the avoidance of sedentary behavior were associated with lower endometrial cancer risk. Baseline recreational physical activity was associated with 33% lower risk (RR = 0.67, 95% CI 0.44-1.03 for 31.5+ vs. <7 MET-hr/week, trend p = 0.007) in the multivariate model without BMI. However, the trend was attenuated after further adjustment for BMI (trend p = 0.18). BMI significantly modified the association between physical activity and endometrial cancer risk (heterogeneity of trends p = 0.01). The inverse relationship was seen only among overweight or obese women (trend p = 0.003) and not in normal weight women (trend p = 0.51). In summary, light and moderate physical activity including daily life activities were associated with lower endometrial cancer risk in our study, especially among women who are overweight or obese.

A transdisciplinary model integrating genetic, physiological, and psychological correlates of voluntary exercise

OBJECTIVE

Physical inactivity contributes to as many as 250,000 premature deaths per year (R. R. Pate et al., 1995). The authors' objective was to test a transdisciplinary model of the ways in which genetic variants, physiological factors, and psychological factors are thought to influence exercise with 64 healthy, regular exercisers.

DESIGN

In a within-subjects design, psychological and physiological responses to exercise were compared with responses to a sedentary activity.

MAIN OUTCOME MEASURES

The authors measured affective state, perceived exertion, heart rate, and temperature change in response to moderate exercise versus sedentary activity. They also quantified genotypes on a single nucleotide polymorphism in the brain-derived neurotrophic factor (BDNF) gene.

RESULTS AND CONCLUSIONS

The data show a relation between increases in positive affective states and acute exercise behavior, as opposed to a sedentary control. The BDNF gene moderated the effect of exercise on mood, heart rate, and perceived exertion. Physiological factors were, in turn, related to mood response, and mood response was a significant correlate of motivation to exercise in the future and of current exercise behavior. The model has potential as a framework for the basic study of the genetic, physiological, and psychological processes involved with voluntary exercise and as a tool for the applied examination of tailored exercise interventions and their efficacy for different subsets of individuals.

Recreational physical activity and sedentary behavior in relation to ovarian cancer risk in a large cohort of US women

Factors that influence circulating sex hormones, such as physical activity, have been proposed to influence ovarian cancer risk; however, results from previous epidemiologic studies have been inconsistent. The authors examined the association among physical activity, sedentary behavior, and ovarian cancer risk in the American Cancer Society Cancer Prevention Study II Nutrition Cohort, a prospective study of cancer incidence and mortality, using information obtained at baseline in 1992. From 1992 to 2001, 314 incident ovarian cancer cases were identified among 59,695 postmenopausal women who were cancer free at enrollment. Cox proportional hazards modeling was used to compute hazard rate ratios while adjusting for potential confounders. No overall association was observed between measures of past physical activity or with recreational physical activity at baseline and risk of ovarian cancer in this study (for the highest category of physical activity compared with none: hazard rate ratio = 0.73, 95% confidence interval: 0.40, 1.34). However, a prolonged duration of sedentary behavior was associated with an increased risk (for > or = 6 vs. < 3 hours per day: hazard rate ratio = 1.55, 95% confidence interval: 1.08, 2.22; p(trend) = 0.01). Results from this study suggest that high levels of sedentary behavior may increase the risk of ovarian cancer, but they do not support a major impact of light and moderate physical activity on ovarian cancer risk.

Diet, nutrition, and the life-course approach to cancer prevention

Cancer results from the interaction of genetic susceptibility and environmental exposures. The diagnosis of cancer is age related; there is a marked increase in cancer incidence after the reproductive years. Nutrient and toxicant exposures are important contributors to the risk of some cancers. Nutrition, as a determinant of growth and body composition, also influences cancer risk, directly due to carcinogens in foods or indirectly by the hormonal and metabolic response to growth and obesity. There is strong evidence that obesity and rapid growth enhance the risk of cancer. The prevention of cancer should start before conception; mothers should start pregnancy with a healthy weight and avoid excessive or low weight gain during pregnancy. Key micronutrients are important for normal embryonic development and fetal growth. Infant growth should be assessed based on optimal health across all stages of the life course, rather than following the present approach of "bigger is better. " This model may increase cancer risk in later life, because bigger is closely linked to fatter. Recent studies of energy expenditure in children indicate that excess energy intakes may have been recommended over the past decades, contributing to the surge in global obesity. Food preferences and habits regarding physical activity and play become set relatively early in life; parents and teachers provide key guidance leading to the adoption of a healthy or an unhealthy lifestyle. Thus, cancer prevention efforts should begin with childhood and continue through all stages of the life course.

Regulation of body mass and management of childhood overweight

Obesity has become an increasingly important public health problem. Recent evidence suggests that obesity has become a close second to tobacco use as a preventable cause of death in the United States. During the past decade an increase in the prevalence of type 2 diabetes in adolescents has been observed. The association of type 2 diabetes and obesity is well established and most adolescents with type 2 diabetes have body mass index (BMI) in a range that would already be considered obese in an adult. Childhood overweight is also associated with the atherosclerotic process. In the Bogalusa autopsy study, Berenson et al. found that the extent of fatty streaks and fibrous plaques in the aorta and coronary arteries was associated with BMI. There are three modalities currently available for the treatment of overweight in children and adolescents, including behavioral approaches, pharmacologic approaches, and surgical approaches. Surgical intervention may be considered if the BMI > or = 40 kg/m2 and a severe medical comorbidity including type 2 diabetes, obstructive sleep apnea or pseudotumor cerebri, or if the BMI is > or = 50 kg/m2 and comorbid conditions such as hypertension, dyslipidemia, or the metabolic syndrome are present. Behavioral intervention is usually made by a psychologist, behavioral therapist, dietician, or exercise physiologist. There is evidence that the effect of behavioral therapy for weight loss in childhood will be longer lasting than that seen in adults.

Fatty acids and exercise affect glucose transport but not tumour growth in F-344 rats

This study examined the effect of diet and exercise on tumour growth, and the effect of dietary fatty acids on glucose uptake. Male Fischer 344 rats were divided into 4 dietary groups and fed for 2 weeks. The diets were 5% (wt/wt) safflower oil, 10% safflower oil, 5% docosahexaenoic acid(DHA)-rich, and 10% DHA-rich. On Day 14 the animals were injected with rat fibrosarcoma tumour cells. After 3 days of tumour growth the animals in each diet group were divided into exercise and nonexercise groups. Exercise was achieved by voluntary wheel running. Dietary intake, body weight, tumour growth, and distance run were determined daily. Two weeks later the animals were euthanized and the following tissues were dissected out: tumour, liver, heart, epididymal fat pads, gastrocnemius, epitrochlearis, and soleus muscles. Glucose transport experiments were performed on the epitrochlearis and soleus muscles whereas phospholipid analysis was completed on the gastrocnemius muscle. We observed no effect of either diet or exercise on tumour growth. The glucose transport data demonstrates that short-term voluntary running can cause increased insulin-sensitive transport and that DHA may inhibit transport. DHA-containing diets were associated with increased oxidation products TBARM. In conclusion, exercise benefits on glucose disposal are maintained in tumour-bearing animals but are influenced by fat content and composition. High DHA diets may also increase oxidative damage in muscle through enhanced TBARM production.

Physical activity and colorectal cancer

Physical activity has been shown to reduce risk of colon cancer. Some studies have shown site-specific associations while others have not. The inverse association between physical activity and colon cancer is consistent although only 7 of 13 studies that have collected both colon and rectal cancer data in the same manner report reduced risk for rectal cancer; four of these studies detected statistically significant inverse associations. The frequency, duration and intensity of activity are important components of a public health message to reduce risk of colon cancer through performance of physical activity. However, difficulties in estimating the exact amount of activity needed and frequency and intensity of activity result in only crude estimates of dose needed for a protective effect. Much of the literature suggest that more intense activity is needed to reduce colon cancer risk and that somewhere between 3.5 and 4 hours of vigorous activity per week may be needed to optimise protection. Several biological mechanisms have been proposed to explain the association between physical activity and colon cancer; many of these mechanisms also support the observation that intense activities are most protective. Biological mechanisms include: physical activity increasing gut motility; enhancing the immune system; decreasing insulin and insulin-like growth factor levels; decreasing obesity; enhancing free radical scavenger systems; and influencing prostaglandin levels. The evidence taken together provides strong support for lack of physical activity being causally related to colon cancer. It has been estimated that 12-14% of colon cancer could be attributed to lack of frequent involvement in vigorous physical activity.

Physical Activity and Risk of Ovarian Cancer: A Prospective Cohort Study in the United States

Increased physical activity may lower the risk of ovarian cancer by reducing the frequency of ovulation, decreasing body fat, or diminishing chronic inflammation. Previous epidemiological studies examining the association between physical activity and risk of ovarian cancer have been inconsistent. We investigated the association of physical activity with ovarian cancer in a prospective cohort of 27,365 individuals from the Breast Cancer Detection Demonstration Project. During 227,045 person-years of follow-up, 121 cases of ovarian cancer were ascertained. Usual physical activity during the past year was assessed by a self-administered questionnaire. After adjusting for potential risk factors for ovarian cancer, the relative risks (95% confidence intervals) across increasing quintiles of total physical activity were 1.0, 0.73 (0.43–1.25), 0.84 (0.50–1.40), 0.56 (0.31–1.00), and 0.70 (0.41–1.21), respectively (P for trend = 0.13). In this prospective cohort study among U.S. women, we found no overall significant association between physical activity and risk of ovarian cancer, although the results are suggestive of an inverse association.

Exercise delays allogeneic tumor growth and reduces intratumoral inflammation and vascularization

This investigation determined whether daily strenuous exercise would alter the progression and regression of an allogeneic lymphoid tumor in mice. We also determined whether exercise would alter the cellular composition and vascularity of the tumor. Female BALB/c mice (age 6-8 wk) were randomly assigned to sedentary control (Con) or daily exercised groups (EXH). EXH mice ran on a treadmill at incremental speeds (20-40 m/min) for 3 h or until fatigue. Each mouse was subcutaneously injected with 20 x 10(6) EL-4 lymphoma cells immediately after the first exercise bout (day 1) and run daily. Tumor volume was measured daily with calipers. In some experiments, mice were euthanized on days 5-10, 12, and 14. Tumors were excised and stained with hematoxylin and eosin or for Factor VIII-associated antigen using immunohistochemistry and analyzed in a blinded fashion under a light microscope. There was no significant treatment main effect found for tumor volumes. Interestingly, a significant treatment x time interaction was found, such that there was a 2-day delay in peak tumor volume and a more rapid tumor regression in EXH. Tumors isolated from Con exhibited significantly higher numbers of apoptotic bodies, blood vessels, macrophages, and neutrophils when compared with EXH. Intratumoral lymphocytes were higher in Con early in tumor growth but higher in EXH at peak tumor size. These data indicate that daily strenuous exercise may influence tumor growth by affecting the microenvironment of the tumor, resulting in a delay in tumor growth and a more rapid regression.

The effect of cardiorespiratory fitness and obesity on cancer mortality in women and men

PURPOSE

The purpose of this study was to determine the independent and combined effects of cardiorespiratory fitness and obesity on all-cause cancer mortality for women and men.

METHODS

Using the Lipids Research Clinics Prevalence Study, we examined the relationship of fitness and obesity on cancer mortality among 2585 women and 2890 men followed from 1972-1976 to 1998. Cardiorespiratory fitness was measured using a treadmill test and obesity was assessed using body mass index (BMI) calculated from measured height and weight. Gender-specific hazard ratios (HR) were calculated from proportional hazard models, which included covariates for age, education, smoking, alcohol intake, Keys score, and menopause (women only).

RESULTS

Adjusted cancer mortality was significantly lower in the most fit quintile relative to the other four quintiles for men (HR = 0.47; 95% CI, 0.27-0.81) but not for women (HR = 0.84; 95% CI, 0.52-1.36). Adjusted cancer mortality was significantly higher in the highest BMI quintile relative to the other four BMI quintiles for women (HR = 1.49; 95% CI, 1.06-2.09) but not for men (HR = 1.05; 95% CI, 0.77-1.43). Further adjustment for BMI on fitness and adjustment for fitness on BMI did not meaningfully change the HR. There were no significant interactions between fitness and obesity in predicting cancer mortality for either women or men.

CONCLUSION

In this study, high fitness was a stronger predictor of cancer mortality in men, whereas high BMI was a stronger predictor of cancer mortality in women.