Physical activity and risks of proximal and distal colon cancers: a systematic review and meta-analysis

Association of sedentary work with colon and rectal cancer: systematic review and meta-analysis

OBJECTIVES

There has been no research on sedentary behaviour in the occupational domain that occupies a large portion of the daily life.

METHODS

We conducted a meta-analysis to investigate the association between sedentary work and colorectal cancer. We searched PubMed, Embase and Cochrane databases up to 12 August 2020 for peer-reviewed journal articles that assessed the association between sedentary work and colon or rectal cancer. Pooled estimates of ORs were obtained using random effects models. Statistical tests for publication bias, heterogeneity and sensitivity analysis were applied.

RESULTS

Of the 5 381 studies initially identified, 23 studies with 64 reports were eligible for inclusion. Sedentary work significantly increased the risk of colon cancer (pooled OR=1.21, 95% CI 1.11 to 1.31, p value ≤0.0001) and rectal cancer (pooled OR=1.08, 95% CI 1.00 to 1.16, p value=0.0395). The adjustment for leisure time physical activity attenuated the association and made the risk estimates non-significant for sedentary behaviour, but the association was independent of sex, control of body mass index and assessment of sedentary behaviour.

CONCLUSIONS

We found evidence of association between sedentary work and the risk of colon or rectal cancer. Limiting excessive sedentary work could be an important means of preventing colon and rectal cancer.

How does occupational physical activity influence health? An umbrella review of 23 health outcomes across 158 observational studies

OBJECTIVE

Physical activity (PA) has substantial benefits across a range of health outcomes. There is uncertainty about the PA-specific health effects, and in particular, the occupational domain. In this umbrella review, we synthesised available evidence on the associations between occupational PA (OPA) and health-related outcomes (including cancer, all-cause mortality and cardiovascular disease). This work informed the development of WHO's guidelines on PA and sedentary behaviour (2020).

DESIGN

Umbrella review of systematic reviews.

DATA SOURCE

We performed a literature search in PubMed, Web of Science, Embase, CINAHL and Sportdiscuss from database inception to 2 December 2019.

ELIGIBILITY CRITERIA FOR SELECTING STUDIES

We included systematic reviews if they contained a quantitative assessment of OPA and its relationship with at least one health-related outcome.

RESULTS

We summarised the evidence of 17 reviews covering 23 unique health-related outcomes. We graded most evidence as low or very low, or moderate quality. We found health benefits for those engaging in high versus low OPA for multiple cancer outcomes (including colon and prostate), ischaemic stroke, coronary heart disease and mental health (ie, mental well-being and life satisfaction). High OPA was associated with unfavourable health outcomes for all-cause mortality in men, mental ill health (ie, depression and anxiety), osteoarthritis, and sleep quality and duration.

CONCLUSIONS

We found favourable associations for most health-related outcomes with high OPA levels, but we also found some evidence for unfavourable associations due to high OPA levels. At this point, there is a need for better quality evidence to provide a unequivocal statement on the health effects of OPA.

Extended healthy lifestyle index and colorectal cancer risk in the Moroccan population

PURPOSE

Little is known about the combined effect of different lifestyle factors on CRC incidence among populations living in developing countries. In this study, we sought to create an Extended Healthy Lifestyle Index (EHLI) and to investigate its association with CRC risk in the Moroccan population.

METHODS

A large case-control study including 1516 cases and 1516 controls, matched on age, sex and center were recruited in 5 Moroccan university hospital centers between 2009 and 2017. EHLI scores, including 9 modifiable factors (smoking, alcohol consumption, physical activity intensity, BMI, fruit and vegetables consumption, drinks that promote weight gain, red and processed meat, relatively unprocessed cereals and/or pulses, and dairy products consumption) were assigned to lifestyle information derived from the participants. We assessed the score based on the answers on each of the nine lifestyle components as unhealthy/un-compliant (0 point), healthy/compliant (1 point) and 0.5 for partial compliance to the recommendation. Conditional logistic regression models were used to assess the association between the EHLI and CRC risk and to estimate multivariate ORs and their 95% confidence intervals (CIs). All potential confounder variables were considered.

RESULTS

After adjusting for potential confounding factors, a significant decrease in the risk of overall CRC was observed when comparing the highest EHLI category with the lowest index category (0.39, 95% CI: 0.33-0.47). These results did not differ by colon or rectum subsite.

CONCLUSION

Combined healthy lifestyle factors are associated with a significantly lower incidence of CRC in Moroccan populations. Prevention strategies should consider targeting of multiple lifestyle factors.

Metabolic Syndrome and Colorectal Cancer Risk: Results of Propensity Score-Based Analyses in a Community-Based Cohort Study

Background: This study aimed to determine the effects of metabolic syndrome (MetS) on colorectal cancer (CRC) using propensity score (PS) methods. Methods: The study subjects were 2417 men and 4568 women from the Korean National Cancer Center (KNCC) Community Cohort enrolled between 2003 and 2010. Odds risks (ORs) and 95% confidence intervals (CIs) using PS matching analysis, regression models adjusted by the PS or stratified into five strata according to PS, and PS weighting methods were calculated. Results: In women, MetS and abnormally high triglyceride (TG) levels were associated with CRC risk using the PS matching analysis (ORs, for MetS, 2.19 (95% CI, 1.10–4.33); for abnormal TG levels, 2.08 (95% CI, 1.07–4.02)). However, there were no significant associations between MetS and TG levels and CRC risk in men. Conclusions: Our study might provide additional evidence that deteriorated metabolic profiles increase the risk of CRC in women rather than men. Thus, this may have an important role in effective population-level interventions for deteriorated metabolic profiles at an early stage.

The effect of exercise-based interventions on health-related quality of life and physical function in older patients with cancer receiving medical antineoplastic treatments: a systematic review

Older patients with cancer are underrepresented in trials investigating the effect of exercise therapy. The aim of this systematic review was to investigate the effect of exercise therapy during medical antineoplastic treatment in older patients (≥ 65 years) with cancer. A systematic review following the Cochrane guidelines was performed. Randomized controlled trials were identified through a systematic literature search in MEDLINE, EMBASE, CENTRAL, and CINAHL up to December 2019. Study selection was performed independently by two reviewers. Four randomized controlled trials published between 2014 and 2019 were included comprising a total of 412 participants. Most participants were diagnosed with breast, prostate or colorectal cancer. The studies were characterized by large differences in design, interventions and outcomes, which prevented meta-analyses. The interventions ranged from 4 weeks to 12 months and involved both supervised and unsupervised exercise programs. Some evidence of beneficial effects from the interventions were documented on physical function, muscle strength, physical activity and cognitive function. No evidence of effects was found for health-related quality of life, aerobic capacity, body composition, cancer-related symptoms and side effects, or for any clinical outcomes. No adverse events were reported. Exercise therapy seems to be safe and feasible in older patients with cancer. However, due to a limited number of studies, small sample sizes and heterogeneity across study design, the effects of exercise in older patients with cancer receiving medical antineoplastic treatment are inconclusive.

The relationship between physical activity and lymphoma: a systematic review and meta analysis

Background

The literature suggests an increased risk between anthropometrics including higher body mass index and lymphoma incidence; however, the association with physical activity remains unclear. A systematic review/meta-analysis was therefore performed to examine this association with physical activity (total, recreational or occupational).

Methods

PubMed, Web of Science and Embase were reviewed from inception to October 2019 identifying relevant observational studies. Non-Hodgkin lymphoma (NHL) including subtypes diffuse large B cell lymphoma, follicular lymphoma and chronic lymphocytic leukemia/small lymphocytic lymphoma, and Hodgkin lymphoma (HL) were analyzed. Included studies reported activity, lymphoma cases, effect size and variability measures, and were restricted to human subjects of any age. Data was pooled generating summary relative risk (RR) estimates with 95% confidence intervals (CI) using random-effects models with primary outcome of histologically confirmed incident lymphoma.

Results

One thousand four hundred studies were initially identified with 18 studies (nine cohort, nine case-control) included in final analysis. Comparing highest vs. lowest activity categories was protective for all lymphoma (RR 0.89, 95%CI 0.81–0.98). Sensitivity analysis demonstrated effect persistence within case-control studies (RR 0.82, 95% CI 0.71–0.96), but not cohort studies (RR 0.95, 95%CI 0.84–1.07). Borderline protective effect was seen for NHL (RR 0.92, 95%CI 0.84–1.00), but not HL (RR 0.72, 95%CI 0.50–1.04). Analysis by NHL subtype or gender showed no effect. Dose response analysis demonstrated a protective effect (p = 0.034) with a 1% risk reduction per 3 MET hours/week (RR 0.99, 95%CI 0.98–1.00).

Conclusions

Physical activity may have a protective effect against lymphoma development; further studies are required to generate recommendations regarding health policy.

Trial registration

This study was registered prospectively at PROSPERO: CRD42020156242.

Association of low skeletal muscle mass with the presence of advanced colorectal neoplasm: integrative analysis using three skeletal muscle mass indices

AIM

This study aimed to evaluate an association between colorectal neoplasm (CRN) and skeletal muscle mass using three widely accepted skeletal muscle mass indices (SMIs) in a large population at average risk.

METHOD

We performed a cross-sectional study using a screening colonoscopy database of 33 958 asymptomatic subjects aged 40-75 years. Appendicular skeletal muscle mass (ASM) was measured using a bioelectrical impedance analyser. ASM adjusted for height squared (ASM/ht² ), weight (ASM/wt) and body mass index (ASM/BMI) were used as indices for muscle mass. Logistic regression models were used to evaluate the association between SMIs and CRN.

RESULTS

In a multivariable-adjusted model, the risk of an advanced CRN increased linearly with decreasing quartiles for all three SMIs. The adjusted odds ratios (ORs) for advanced CRN in quartiles 1, 2 and 3 of ASM/wt compared with that in quartile 4 were 1.279, 1.196 and 1.179, respectively (P_trend  = 0.017); for ASM/BMI, ORs were 1.307, 1.144 and 1.091, respectively (P_trend  = 0.002); and for ASM/ht² , ORs were 1.342, 1.169 and 1.062, respectively (P_trend  = 0.002). The risk of distally located advanced CRN was higher in quartile 1 than in quartile 4 for all three SMIs (ASM/wt, OR = 1.356; ASM/BMI, OR = 1.383; ASM/ht² , OR = 1.430).

CONCLUSION

Our study demonstrated that low skeletal muscle mass was consistently associated with the presence of advanced CRN in a population at average risk regardless of the operational definition of the SMI, and it was particularly associated with distal advanced CRN.

Voluntary exercise in mesothelioma: effects on tumour growth and treatment response in a murine model

Objective

There is substantial evidence that exercise can safely reduce the risk of cancer and improve survival in different human cancer populations. Long latency periods associated with carcinogen–induced cancers like asbestos induced mesothelioma provide an opportunity to implement exercise as an intervention to delay or prevent disease development. However, there are limited studies investigating the ability of exercise to prevent or delay cancer, and exercise as a preventive strategy has never been assessed in models with a known carcinogen. We investigated the potential of voluntary exercise (VE) to delay development of asbestos related disease (ARD) in our well-characterised, asbestos induced MexTAg model of mesothelioma.

Results

Asbestos exposed MexTAg mice were given continuous or delayed access to VE and ARD assessed over time. We found that the addition of VE did not affect ARD development in asbestos exposed MexTAg mice. However, non–asbestos exposed, aged matched control mice participated in significantly more VE behaviours, suggesting subclinical development of ARD after asbestos exposure had a greater impact on VE participation than age alone. These data highlight the importance of model choice and the potential limitation that some pre–clinical studies may not accurately represent the clinical paradigm, particularly in the context of prevention studies.

Aggressive Colorectal Cancer in the Young

Despite the steady decline in the incidence of colorectal cancer (CRC) and cancer-related mortality in Americans of 50 years and older over the last few decades, there has been a disturbing trend of steadily rising incidence in early-onset colorectal cancer (EOCRC), defined as CRC in those younger than 50 years. With the incidence of EOCRC increasing from 4.8 per 100,000 in 1988 to 8.0 per 100,000 in 2015, and with the decreased rates in those older than 50 years largely attributed to improved screening in the older population, new screening recommendations have recently lowered the age for screening average-risk individuals from 50 to 45. EOCRC has been found to present differently from late-onset CRC, with a higher proportion of patients presenting with left-sided and rectal cancer, more aggressive histological features, and more advanced stage at the time of diagnosis. This article reviews the most recent evidence from population-based studies and institutional series, as well as the newest screening guidelines, and provides an up-to-date summary of our current understanding of EOCRC, from clinical presentation to tumor biology and prognosis, and future directions in treatment and prevention.

The Moderating Effects of Social Support and Stress on Physical Activity in African American Women

BACKGROUND

African American women participate in less physical activity (PA), have higher rates of chronic disease, and report higher perceived stress relative to other race and sex demographic groups.

PURPOSE

Based on the stress-buffering hypothesis, this study tested the hypothesis that social support would buffer the negative effects of perceived stress on moderate-to-vigorous PA (MVPA) under high, but not low, perceived stress.

METHODS

Participants were 143 African American women (mean [M] age = 43.94, standard deviation [SD] = 8.62; M body mass index = 37.94, SD = 8.11) enrolled in the Families Improving Together (FIT) for Weight Loss Trial. Average daily minutes of MVPA were obtained via 7 day accelerometer estimates at baseline and 8 and 16 weeks.

RESULTS

A multilevel growth model demonstrated a significant three-way interaction between stress, social support, and time (B = -0.31, standard error [SE] = 0.14, p = .03). Simple slopes analyses revealed that, at baseline, among participants with high social support (+1 SD), stress was positively associated with greater MVPA (B = 0.49, SE = 0.18, p = .008), whereas among participants with low social support (-1 SD), stress was not significantly associated with MVPA (B = -0.04, SE = 0.14, p = .81). However, at 8 and 16 weeks, stress was not significantly associated with MVPA for either high or low support groups.

CONCLUSIONS

Findings highlight the importance of integrating constructs of stress and social support into future physical activity intervention programs for African American women and the need to evaluate changes in stress and social support longitudinally.

Estimation of Absolute Risk of Colorectal Cancer Based on Healthy Lifestyle, Genetic Risk, and Colonoscopy Status in a Population-Based Study

BACKGROUND & AIMS

Estimates of absolute risk of colorectal cancer (CRC) are needed to facilitate communication and better inform the public about the potentials and limits of cancer prevention.

METHODS

Using data from a large population-based case-control study in Germany (Darmkrebs: Chancen der Verhütung durch Screening [DACHS] study, which began in 2003) and population registry data, we calculated 30-year absolute risk estimates for development of CRC based on a healthy lifestyle score (derived from 5 modifiable lifestyle factors: smoking, alcohol consumption, diet, physical activity, and body fatness), a polygenic risk score (based on 90 single-nucleotide polymorphisms), and colonoscopy history.

RESULTS

We analyzed data from 4220 patients with CRC and 3338 individuals without CRC. Adherence to a healthy lifestyle and colonoscopy in the preceding 10 years were associated with a reduced relative risk of CRC in men and women. We observed a higher CRC risk in participants with high or intermediate genetic risk scores. For 50-year-old men and women without a colonoscopy, the absolute risk of CRC varied according to the polygenic risk score and the healthy lifestyle score (men, 3.5%-13.4%; women, 2.5%-10.6%). For 50-year-old men and women with a colonoscopy, the absolute risk of developing CRC was much lower but still varied according to the polygenic risk score and the healthy lifestyle score (men, 1.2%-4.8%; women, 0.9%-4.2%). Among all risk factor profiles, the 30-year absolute risk estimates consistently decreased with adherence to a healthy lifestyle.

CONCLUSIONS

In a population-based study, we found that a colonoscopy can drastically reduce the absolute risk of CRC and that the genetically predetermined risk of CRC can be further reduced by adherence to a healthy lifestyle. Our results show the magnitude of CRC prevention possible through colonoscopy and lifestyle at a predefined genetic risk. This observational study has been registered in the German Clinical Trials Register (DRKS00011793), which is a primary registry in the World Health Organization Registry Network.

Early-onset colorectal cancer: initial clues and current views

Over the past several decades, the incidence of early-onset colorectal cancer (EOCRC; in patients <50 years old) has increased at an alarming rate. Although robust and scientifically rigorous epidemiological studies have sifted out environmental elements linked to EOCRC, our knowledge of the causes and mechanisms of this disease is far from complete. Here, we highlight potential risk factors and putative mechanisms that drive EOCRC and suggest likely areas for fruitful research. In addition, we identify inconsistencies in the evidence implicating a strong effect of increased adiposity and suggest that certain behaviours (such as diet and stress) might place nonobese and otherwise healthy people at risk of this disease. Key risk factors are reviewed, including the global westernization of diets (usually involving a high intake of red and processed meats, high-fructose corn syrup and unhealthy cooking methods), stress, antibiotics, synthetic food dyes, monosodium glutamate, titanium dioxide, and physical inactivity and/or sedentary behaviour. The gut microbiota is probably at the crossroads of these risk factors and EOCRC. The time course of the disease and the fact that relevant exposures probably occur in childhood raise important methodological issues that are also discussed.

The Impact of a Structured, Supervised Exercise Program on Daily Step Count in Sedentary Older Adults With and Without HIV

BACKGROUND

People with HIV (PWH) may have lower daily activity levels compared with persons without HIV. We sought to determine the impact of initiating a supervised exercise program on the daily step count of sedentary PWH and uninfected controls.

METHODS

PWH and controls, aged 50-75, were enrolled in a 24-week supervised exercise program. All individuals were given a pedometer and instructed in regular use. A linear mixed model taking into account random effects was used to model daily step count.

RESULTS

Of 69 participants that began the study, 55 completed and 38 (21 PWH, 17 controls) had complete pedometer data. Baseline daily step count on nonsupervised exercise day was (estimated geometric mean, 95% confidence interval) 3543 (1306 to 9099) for PWH and 4182 (1632 to 10,187) for controls. Both groups increased daily steps on supervised [43% (20 to 69)%, P < 0.001] but not unsupervised exercise days [-12% (-24 to 1)%, P = 0.071]. Compared with controls, PWH had 26% [(-47 to 4)%, P = 0.08] fewer daily steps on days with supervised exercise and 35% [-53 to -10)%, P = 0.011] fewer daily steps on days without supervised exercise. Higher body mass index (per 1 unit) and smoking were associated with fewer daily steps [-5% (-9 to -1)%; -49% (-67 to -23)%; P ≤ 0.012]. Days with precipitation [-8% (-13 to -3)%, P = 0.002] or below freezing [-10% [-15 to -4)%, P < 0.001] were associated with fewer steps.

CONCLUSION

Supervised exercise increased daily step counts in sedentary individuals, but at the expense of fewer steps on nonsupervised exercise days.

American College of Sports Medicine Roundtable Report on Physical Activity, Sedentary Behavior, and Cancer Prevention and Control

INTRODUCTION

The American College of Sports Medicine convened an International Multidisciplinary Roundtable on Exercise and Cancer in March 2018 to evaluate and translate the evidence linking physical activity and cancer prevention, treatment, and control. This article discusses findings from the Roundtable in relation to the biologic and epidemiologic evidence for the role of physical activity in cancer prevention and survival.

RESULTS

The evidence supports that there are a number of biologically plausible mechanisms, whereby physical activity can influence cancer risk, and that physical activity is beneficial for the prevention of several types of cancer including breast, colon, endometrial, kidney, bladder, esophageal, and stomach. Minimizing time spent in sedentary behavior may also lower risk of endometrial, colon and lung cancers. Conversely, physical activity is associated with higher risk of melanoma, a serious form of skin cancer. Further, physical activity before and after a cancer diagnosis is also likely to be relevant for improved survival for those diagnosed with breast and colon cancer; with data suggesting that postdiagnosis physical activity provides greater mortality benefits than prediagnosis physical activity.

CONCLUSIONS

Collectively, there is consistent, compelling evidence that physical activity plays a role in preventing many types of cancer and for improving longevity among cancer survivors, although the evidence related to higher risk of melanoma demonstrates the importance of sun safe practices while being physically active. Together, these findings underscore the importance of physical activity in cancer prevention and control. Fitness and public health professionals and health care providers worldwide are encouraged to spread the message to the general population and cancer survivors to be physically active as their age, abilities, and cancer status will allow.

Prevention and adherence in Rheumatic and Musculoskeletal disease

Rheumatic and Musculoskeletal Diseases (RMDs) are chronic conditions that affect a substantial number of people. RMDs are significantly related to co-morbidity. Therefore, focusing on prevention in RMDs is of importance to promote and maintain health. Prevention includes primary-, secondary-, tertiary-, and clinical prevention. Primary prevention aims to prevent the onset of disease before the disease process begins, secondary prevention includes detecting and reducing disease and risk factors at the earliest possible point, and tertiary prevention aims to limit the influence of a recognized or verified disease and to address or reduce further development or worsening of the disease, including physical and psychosocial disability. Clinical prevention attempts to integrate prevention into the disease management to limit disease progression and prevent complications and relapse. This chapter will focus on the evidence for prevention and highlight how innovations and trends can contribute by using digital technologies as an example.

Mild Exercise Rescues Steroidogenesis and Spermatogenesis in Rats Submitted to Food Withdrawal

The present investigation was undertaken to increase our insight into the molecular basis of the physiological changes in rat testis induced by food withdrawal, and to clarify whether reduced testicular function can be ameliorated by mild exercise. Male rats were selected for four separate experiments. The first of each group was chow-fed, the second was chow-fed and submitted to exercise (5 bouts in total for 30 min at 15 m/min, and 0° inclination), the third was submitted to food withdrawal (66 h) and the fourth was submitted to food withdrawal and to exercise. At the end of experiments, we investigated (i) serum and testicular sex hormone levels; (ii) protein levels of StAR, 3β-Hydroxysteroid dehydrogenase (3β-HSD) and P450 aromatase, which play a key role in steroid hormone biosynthesis; and (iii) protein levels of mitotic and meiotic markers of spermatogenesis in rats, in relation to testis morphology and morphometry. We found that mild exercise or food withdrawal alone induced a significant increase or decrease in both serum and testis testosterone levels, respectively. Interestingly, we found that these levels were brought back to basal levels when food withdrawal was combined with mild exercise. The changes in testosterone levels observed in our experimental groups correlated well with the expression of steroidogenic enzymes as well as with spermatogenic activity. With mild exercise the increased testosterone/17β-estradiol (T/E2) ratio in the testis correlated with an increased spermatogenic activity. The T/E2 ratio dropped in fasted rats and was significantly reversed when food withdrawal was combined with exercise. Histological and morphometric analyses confirmed that spermatogenic activity varied in concomitance with each experimental condition. Importantly, the testis and serum T/E2 ratios correlated, confirming that exercise rescues the decline in food withdrawal-induced spermatogenesis. In conclusion, this study highlights that mild exercise normalizes the reduced spermatogenic activity caused by food withdrawal through the modulation of the steroidogenic pathway and restoring the T/E2 ratio, underlining the beneficial effects of mild exercise on the prevention and/or amelioration of reduced testis function caused by restricted caloric intake.

Targeting of oncogenic signaling pathways by berberine for treatment of colorectal cancer

Studies indicate that inhibiting a single signaling pathway or one single product of a gene is insufficient for the prevention and treatment of cancer. This is due to the fact that dysregulation must occur in more than 500 genes in order to produce a cancerous phenotype. Despite this evidence, available drugs used for cancer treatment focus on a single target. Meanwhile, berberine as a nutraceutical is capable of targeting various processes involved in tumor development including proliferation, invasion, angiogenesis, and metastasis. In comparison with synthetic agents, berberine is cheaper, safer, and more available. Berberine has shown anti-inflammatory properties which make it an ideal option in order to prevent inflammation-associated cancers. Colorectal cancer is one of the most common cancers all over the world and its incidence is increasing each day. Therefore, further investigations about berberine could be helpful in the discovery of novel agents for preventing and/or treating colorectal cancer. This review emphasizes the studies investigating the roles of berberine in colorectal cancer such as controlling cell signaling pathways, inducing apoptosis, regulating microRNAs, attenuating oxidative stress, and affecting inflammation.

Age Moderates the Effect of Self-Paced Exercise on Exercise Adherence among Overweight Adults

Objective: The present study tested the hypothesis that the effect of self-paced exercise on adherence to exercise programs is more pronounced with increasing age. Method: Fifty-nine low-active overweight adults (18-65 years) were encouraged to walk 30 to 60 min/day and randomized to either self-paced (n = 30) or prescribed moderate-intensity (n = 29) conditions. Results: The effect of study condition was moderated by age (main effect: b = 6.14, SE = 2.54, p = .02; Condition × Age: b = -11.55, SE = 3.77, p < .01), such that among participants >50 years, those in the self-paced condition exercised 6 more min/day than participants in the prescribed moderate-intensity condition (p = .02), whereas among participants <50 years, those in the self-paced condition exercised 5.4 fewer min/day compared with those in the moderate-intensity condition (p = .05). Affective response to physical activity did not mediate the moderating effect of age. Discussion: As age increases, adults may be more likely to adhere to self-paced versus prescribed moderate-intensity exercise.

Colorectal Cancer in the Young: Epidemiology, Prevention, Management

Colorectal cancer (CRC) incidence rates in the United States overall have declined since the mid-1980s because of changing patterns in risk factors (e.g., decreased smoking) and increases in screening. However, this progress is increasingly confined to older adults. CRC occurrence has been on the rise in patients younger than age 50, often referred to as early-onset disease, since the mid-1990s. Young patients are more often diagnosed at an advanced stage and with rectal disease than their older counterparts, and they have numerous other unique challenges across the cancer management continuum. For example, young patients are less likely than older patients to have a usual source of health care; often need a more complex treatment protocol to preserve fertility and sexual function; are at higher risk of long-term and late effects, including subsequent primary malignancies; and more often suffer medical financial hardship. Diagnosis is often delayed because of provider- and patient-related factors, and clinicians must have a high index of suspicion if young patients present with rectal bleeding or changes in bowel habits. Educating primary care providers and the larger population on the increasing incidence and characteristic symptoms is paramount. Morbidity can further be averted by increasing awareness of the criteria for early screening, which include a family history of CRC or polyps and a genetic predisposition.

Tea polyphenols and their chemopreventive and therapeutic effects on colorectal cancer

Colorectal cancer (CRC), a multifactorial disease, is usually induced and developed through complex mechanisms, including impact of diet and lifestyle, genomic abnormalities, change of signaling pathways, inflammatory response, oxidation stress, dysbiosis, and so on. As natural polyphenolic phytochemicals that exist primarily in tea, tea polyphenols (TPs) have been shown to have many clinical applications, especially as anticancer agents. Most animal studies and epidemiological studies have demonstrated that TPs can prevent and treat CRC. TPs can inhibit the growth and metastasis of CRC by exerting the anti-inflammatory, anti-oxidative or pro-oxidative, and pro-apoptotic effects, which are achieved by modulations at multiple levels. Many experiments have demonstrated that TPs can modulate several signaling pathways in cancer cells, including the mitogen-activated protein kinase pathway, phosphatidylinositol-3 kinase/Akt pathway, Wnt/β-catenin pathway, and 67 kDa laminin receptor pathway, to inhibit proliferation and promote cell apoptosis. In addition, novel studies have also suggested that TPs can prevent the growth and metastasis of CRC by modulating the composition of gut microbiota to improve immune system and decrease inflammatory responses. Molecular pathological epidemiology, a novel multidisciplinary investigation, has made great progress on CRC, and the further molecular pathological epidemiology research should be developed in the field of TPs and CRC. This review summarizes the existing in vitro and in vivo animal and human studies and potential mechanisms to examine the effects of tea polyphenols on CRC.

Across-Site Differences in the Mechanism of Alcohol-Induced Digestive Tract Carcinogenesis: An Evaluation by Mediation Analysis

A genetic variant on aldehyde dehydrogenase 2 (ALDH2 rs671, Glu504Lys) contributes to carcinogenesis after alcohol consumption. Somewhat conversely, the ALDH2 Lys allele also confers a protective effect against alcohol-induced carcinogenesis by decreasing alcohol consumption due to acetaldehyde-related adverse effects. Here, we applied a mediation analysis to five case-control studies for head and neck, esophageal, stomach, small intestine, and colorectal cancers, with 4,099 cases and 6,065 controls, and explored the potentially heterogeneous impact of alcohol drinking on digestive tract carcinogenesis by decomposing the total effect of the ALDH2 Lys allele on digestive tract cancer risk into the two opposing effects of the carcinogenic effect (direct effect) and the protective effect (indirect effect mediated by drinking behavior). Alcohol was associated with an increased risk of most digestive tract cancers, but significant direct effects were observed only for upper gastrointestinal tract cancer risk, and varied substantially by site, with ORs (95% confidence interval) of 1.83 (1.43-2.36) for head and neck cancer, 21.15 (9.11-49.12) for esophageal cancer, and 1.65 (1.38-1.96) for stomach cancer. In contrast, a significant protective indirect effect was observed on risk for all cancers, except small intestine cancer. These findings suggest that alcohol is a major risk factor for digestive tract cancers, but its impact as a surrogate for acetaldehyde exposure appears heterogeneous by site. Meanwhile, the behavior-related effect of the ALDH2 Lys allele results in a decreased risk of most digestive tract cancers. SIGNIFICANCE: These findings support that genetic alcohol avoidance is a factor against alcohol-induced cancers.

Development of a Tool to Increase Physical Activity among People at Risk for Diabetes in Low-Resourced Communities in Cape Town

Targeted lifestyle interventions, including physical activity (PA), have been proven to prevent or delay the onset of diabetes. South Africa’s unique context, complex environment and varied cultures and ethnicities require tailored interventions. Our objective was to develop a context-appropriate tool for the South African Diabetes Prevention Programme’s PA lifestyle component in order to enable people at risk of developing diabetes to adopt PA. We used mixed methods to inform the development of the tool. Descriptive analyses of baseline survey data included socio-demographics, anthropometrics, blood pressure and biochemical measurements, reported medical history, PA behaviours, and built environment information. Focus group discussions assisted in understanding perceived challenges, barriers and facilitators/opportunities to PA. A literature search on successful South African PA interventions was done, and PA experts in Cape Town were consulted. Quantitative data were analysed using the software R, version 3.4.4 and qualitative data were thematically analysed. Participants (n = 316) recruited were mostly black (54.4%) and of mixed-ancestry (44.6%); they were mainly female (80.1%), obese (75.2%), and had an haemoglobin A1c (HbA1c) above 5.7% (65.5%), with 30% having hypertension and 87% (self-reported) meeting the World Health Organisation (WHO) PA recommendation. Main barriers to PA practice were safety, cost and accessibility of sports facilities, and laziness. We included practising moderate-intensity aerobic and resistance exercises and take-home self-help materials as recommended. By combining results, we produced a targeted, practical and promotional PA booklet.

Post Genome-Wide Gene-Environment Interaction Study Using Random Survival Forest: Insulin Resistance, Lifestyle Factors, and Colorectal Cancer Risk

Molecular and genetic pathways of insulin resistance (IR) connecting colorectal cancer and obesity factors in postmenopausal women remain inconclusive. We examined the IR pathways on both genetic and phenotypic perspectives at the genome-wide level. We further constructed colorectal cancer risk profiles with the most predictive IR SNPs and lifestyle factors. In our earlier genome-wide association gene-environmental interaction study, we used data from a large cohort of postmenopausal women in the Women's Health Initiative Database for Genotypes and Phenotypes Study and identified 58 SNPs in relation to IR phenotypes. In this study, we evaluated the identified IR SNPs and selected 34 lifestyles for their association with colorectal cancer risk in a total of 11,078 women (including 736 women with colorectal cancer) using a 2-stage multimodal random survival forest analysis. In overall and subgroup (defined via body mass index, exercise, and dietary-fat intake) analyses, we identified 2 SNPs (LINC00460 rs1725459 and MTRR rs722025) and lifetime cumulative exposure to estrogen (oral contraceptive use) and cigarette smoking as the most common and strongest predictive markers for colorectal cancer risk across the analyses. The combinations of genetic and lifestyle factors had much greater impact on colorectal cancer risk than any individual risk factors, and a possible synergism existed to increase colorectal cancer risk in a gene-behavior dose-dependent manner. Our findings may inform research on the role of IR in the etiology of colorectal cancer and contribute to more accurate prediction of colorectal cancer risk, suggesting potential intervention strategies for women with specific genotypes and lifestyles to reduce their colorectal cancer risk.

Global patterns and trends in colorectal cancer incidence in young adults

OBJECTIVE

Early-onset colorectal cancer (CRC) is increasing in the USA despite rapid declines in older ages. Similar patterns are reported in Australia and Canada, but a comprehensive global analysis of contemporary data is lacking.

DESIGN

We extracted long-term data from Cancer Incidence in Five Continents and supplemental sources to report on worldwide CRC incidence rates and trends by age (20-49 years and ≥50 years) through diagnosis year 2012 or beyond (Australia, Finland, New Zealand, Norway, Sweden, USA).

RESULTS

During 2008-2012, age-standardised CRC incidence rates in adults <50 ranged from 3.5 per 100 000 (95% CI 3.2 to 3.9) in India (Chennai) to 12.9 (95% CI 12.6 to 13.3) in Korea. During the most recent decade of available data, incidence in adults <50 was stable in 14 of 36 countries; declined in Austria, Italy and Lithuania; and increased in 19 countries, nine of which had stable or declining trends in older adults (Australia, Canada, Denmark, Germany, New Zealand, Slovenia, Sweden, UK and USA). In Cyprus, Netherlands and Norway, inclines in incidence in young adults were twice as rapid as those in older adults (eg, Norway average annual per cent change (AAPC), 1.9 (95% CI 1.4 to 2.5) vs 0.5 (95% CI 0.3 to 0.7)). Among most high-income countries with long-term data, the uptick in early-onset disease began in the mid-1990s. The steepest increases in young adults were in Korea (AAPC, 4.2 (95% CI 3.4 to 5.0)) and New Zealand (AAPC, 4.0 (95% CI 2.1 to 6.0)).

CONCLUSION

CRC incidence increased exclusively in young adults in nine high-income countries spanning three continents, potentially signalling changes in early-life exposures that influence large bowel carcinogenesis.

Revisiting the impact of lifestyle on colorectal cancer risk in a gender perspective

Colorectal cancer (CRC) is a leading cause of cancer-related mortality in the world. Patterns and trends in CRC incidence and mortality correlate with increasing adoption of Western lifestyles and with the overweight/obesity epidemic. Both genetic background and a range of modifiable environmental/lifestyle factors play a role in CRC etiology. Among these the links of body weight, dietary patterns and physical activity (PA) behavior with CRC risk are some of the strongest for any type of cancer, with a different impact in women and men. Nonetheless, gender disparities still represent a neglected aspect of CRC management. This review sheds light on gender-related association of obesity and different dietary/PA habits with CRC risk, highlighting the importance of lifestyle modifications in the prevention of this neoplastic disease. In this scenario, intervention studies are strongly recommended to define the most effective dietary/PA regimens for primary prevention of cancer in women and men.

Trends of colorectal cancer incidence by education and socioeconomic status in Finland

Background: The aim of this study was to investigate if the incidence of colorectal cancer (CRC) is associated with education and socioeconomic status (SES) in Finland, and if there are any changes in incidence differences between the groups over the period 1976-2014.Material and methods: CRC cases (N = 77,614) were retrieved from the Finnish Cancer Registry and linked with information on the education level and SES from Statistics Finland. We used Poisson regression model to quantify differences in incidence rates between the groups, and to assess changes over calendar time.Results and conclusions: Colon cancer incidence was higher among the highly educated, than in those with basic education. Similar differences were observed by SES in men. Incidence rates increased steeply over time among men with basic education (from 16.7/100,000 in 1976-1979 to 31.8 in 2010-2014), resulting in narrowed differences between the groups (p < .001). Incidence trends of proximal and distal colon and rectal cancer in men showed similar patterns. Heterogeneity across time periods by SES was observed only in colon cancer incidence in men (p = .009). No such large differences were detected in women. Steep increase in colon cancer incidence in men with basic education, and the respective persistent high incidence in the highly educated highlights the importance of focusing the preventive measures on modifiable lifestyle factors in order to reduce CRC incidence and to narrow the educational and socioeconomic health differences.

Sugar-sweetened beverages and colorectal cancer risk in the California Teachers Study

BACKGROUND

The association between sugar-sweetened beverage (SSB) consumption and colorectal cancer (CRC) risk remains unclear and published data are limited.

METHODS

The analytic cohort included 99,798 women, free of cancer at baseline, from the California Teachers Study, a longitudinal cohort comprised of 133,477 female teachers and administrators who were active or recently retired members of the California State Teachers Retirement System in 1995. SSB consumption constituted caloric soft drinks, sweetened bottled waters and teas, and fruit drinks, derived from a self-administered food frequency questionnaire. Consumption was divided into four categories: Rare or never, >rare/never to <1 serving/week, ≥1 serving/week to <1 serving/day, and ≥1 serving/day. CRC endpoints were based on annual linkage with California Cancer Registry, defined as first diagnosis of CRC, and classified following the Surveillance, Epidemiology, and End Results Program coding system. Multivariable-adjusted Cox proportional hazards models were used to generate hazard ratios (HR) and 95% confidence intervals (CI) for assessing the association between SSB consumption and incident CRC.

RESULTS

A total of 1,318 incident CRC cases were identified over 20 years of follow-up (54.5% proximal colon and 45.5% distal colorectum). Compared with rare/never consumers, the multivariable-adjusted HRs (95% CI) were 1.14 (0.86, 1.53) for total CRC; 1.11 (0.73, 1.68) for proximal colon; and 1.22 (0.80, 1.86) for distal colorectum cancers among women consuming ≥ 1 serving/day of SSBs.

CONCLUSION

SSBs were not significantly associated with CRC risk. The biological effects of high SSB consumption make it important to continue to evaluate whether SSBs are associated with CRC. Additionally, future studies should further assess SSBs in large, racial/ethnically diverse cohorts of males and females, and, if feasible, address changes in SSB consumption over time.

Lifestyle and dietary environmental factors in colorectal cancer susceptibility

Colorectal cancer (CRC) incidence changes with time and by variations in diet and lifestyle, as evidenced historically by migrant studies and recently by extensive epidemiologic evidence. The worldwide heterogeneity in CRC incidence is strongly suggestive of etiological involvement of environmental exposures, particularly lifestyle and diet. It is established that physical inactivity, obesity and some dietary factors (red/processed meats, alcohol) are positively associated with CRC, while healthy lifestyle habits show inverse associations. Mechanistic evidence shows that lifestyle and dietary components that contribute to energy excess are linked with increased CRC via metabolic dysfunction, inflammation, oxidative stress, bacterial dysbiosis and breakdown of gut barrier integrity while the reverse is apparent for components associated with decreased risk. This chapter will review the available evidence on lifestyle and dietary factors in CRC etiology and their underlying mechanisms in CRC development. This short review will also touch upon available information on potential gene-environment interactions, molecular sub-types of CRC and anatomical sub-sites within the colorectum.

CAC1 knockdown reverses drug resistance through the downregulation of P-gp and MRP-1 expression in colorectal cancer

CDK2-associated cullin domain 1 (CAC1) is as a novel cell cycle regulator widely expressed in colorectal cancer (CRC). However, its expression and function in drug resistant CRC cells remains elusive. Therefore, the present study aimed to assess the biochemical function and relevance of CAC1 in drug resistant CRC cells, and detect the potential mechanism. For this purpose, a total of 83 CRC cases were collected for the immunohistochemical analysis of CAC1 expression. Functional studies (stable transfection, flow cytometry, colony formation, and invasion and migration assays) were performed in SW480, LoVo and their corresponding 5-FU resistant cells. In addition, a nude mice xenograft model was established for further observation in vivo. In the present study, CAC1 protein expression was higher in CRC tissues than that in normal tissues (P<0.05). Furthermore, CAC1 protein expression was higher in SW480/5-FU cells than in SW480 cells. CAC1 knockdown arrested 5-FU resistant cells at the G1/S phase and increased the sensitivity of 5-FU resistant cells to 5-FU by inducing apoptosis. In addition, CAC1 reduced the invasive and migration ability of SW480/5-FU and LoVo/5-FU cells in vitro, and reduced their tumorigenicity and metastatic ability in vivo. Finally, CAC1 knockdown resulted in decreased P-glycoprotein and MRP-1 protein expression. Based on these results, it can be concluded that CAC1 plays an important role in the occurrence and promotion of drug resistance in CRC. Therefore, the knockdown of CAC1 may be considered as a new strategy for the development of CRC drug resistance treatments in the future.

Effect of physical fitness on colorectal tumor development in patients with familial adenomatous polyposis

Although accumulated epidemiological evidence indicates that a good physical fitness level may prevent the development of sporadic colorectal cancer (CRC), few studies have examined the effect of physical fitness level on familial adenomatous polyposis (FAP). This cross-sectional study aimed to examine the relationship between physical fitness and CRC development in patients with FAP.A total of 119 patients (54 male; 65 female) with FAP, aged 17 to 73 years, underwent a step test to induce exercise stress. Predicted maximal oxygen uptake (VO2max) was calculated for each patient by using heart rate as an index of physical fitness. The association of VO2max with the presence or absence of CRC and polyp diameter was examined. Patients with FAP were divided into 3 categories according to their VO2max (high, medium, and low). The association between maximum polyp size and VO2max among the patients with FAP without a history of colectomy was examined.The risk of CRC was significantly higher in the low VO2max group than in the high VO2max group (odds ratio = 4.07; 95% confidence interval, 1.02-16.26). The maximum polyp diameter was significantly negatively correlated with the VO2max among the patients with FAP without a history of colectomy (r = -.44, P = .01). In the multiple linear regression analysis, maximum polyp diameter was independently correlated with VO2max.Our results suggest a preventive association between physical fitness and CRC development or colorectal adenoma growth exists in patients with FAP.

Colorectal cancer in Saudi Arabia as the proof-of-principle model for implementing strategies of predictive, preventive, and personalized medicine in healthcare

Colorectal cancer (CRC) is the most commonly diagnosed cancer among Saudi males and ranks third in females with up to 73% of cases diagnosed at late stage. This review provides an analysis of CRC situation in the Kingdom of Saudi Arabia (KSA) from healthcare perspective. A PUBMED (1986-2018) search was done to identify publications focusing on CRC in KSA. Due to reports of increased CRC incidence among young age group (< 50), and given the young population of KSA, the disease may burden the national healthcare system in the next decades. Environmental factors attributed to increasing incidence rates of CRC include red meat consumption, sedentary lifestyle, and increased calorie intake. Despite substantial investment in healthcare, attention to predictive diagnostics and targeted prevention is lacking. There is a need to develop national screening guidelines based on evidence that supports a reduction in incidence and mortality of CRC when screening is implemented. Future approaches are discussed based on multi-level diagnostics, risk assessment, and population screening programs focused on the needs of young populations that among others present the contents of the advanced approach by predictive, preventive, and personalized medicine. Recommendations are provided that could help to develop policies at regional and national levels. Countries with demographics and lifestyle similar to KSA may gain insights from this review to shape their policies and procedures.

Cardiorespiratory fitness and incident lung and colorectal cancer in men and women: Results from the Henry Ford Exercise Testing (FIT) cohort

BACKGROUND

To the authors' knowledge, the relationship between cardiorespiratory fitness (CRF) and lung and colorectal cancer outcomes is not well established.

METHODS

A retrospective cohort study was performed of 49,143 consecutive patients who underwent clinician-referred exercise stress testing from 1991 through 2009. The patients ranged in age from 40 to 70 years, were without cancer, and were treated within the Henry Ford Health System in Detroit, Michigan. CRF, measured in metabolic equivalents of task (METs), was categorized as <6 (reference), 6 to 9, 10 to 11, and ≥12. Incident cancer was obtained through linkage to the cancer registry and all-cause mortality from the National Death Index.

RESULTS

Participants had a mean age of 54 ± 8 years. Approximately 46% were female, 64% were white, 29% were black, and 1% were Hispanic. The median follow-up was 7.7 years. Cox proportional hazard models, adjusted for age, race, sex, body mass index, smoking history, and diabetes, found that those in the highest fitness category (METs ≥12) had a 77% decreased risk of lung cancer (hazard ratio [HR], 0.23; 95% CI, 0.14-0.36) and a 61% decreased risk of incident colorectal cancer (HR, 0.39; 95% CI, 0.23-0.66; with additional adjustment for aspirin and statin use). Among those diagnosed with lung and colorectal cancer, those with high fitness had a decreased risk of subsequent death of 44% and 89%, respectively (HR, 0.56 [95% CI, 0.32-1.00] and HR, 0.11 [95% CI, 0.03-0.37], respectively).

CONCLUSIONS

In what to the authors' knowledge is the largest study performed to date, higher CRF was associated with a lower risk of incident lung and colorectal cancer in men and women and a lower risk of all-cause mortality among those diagnosed with lung or colorectal cancer.

Physically active individuals have a 23% lower risk of any colorectal neoplasia and a 27% lower risk of advanced colorectal neoplasia than their non-active counterparts: systematic review and meta-analysis of observational studies

BACKGROUND

Few studies have examined the associations between physical activity (PA), sedentary behaviour (SB) and risk of colorectal neoplasia (CN).

METHODS

We systematically searched Medline, Embase, PsyInfo, Cochrane and other sources from their inception to 30 September 2018 for cohort, case-control and cross-sectional studies that evaluated these associations in asymptomatic, average-risk subjects. Random-effect models were used to estimate relative risks (RRs) of any-type CN, advanced CN, and non-advanced CN, respectively, in individuals with the highest versus the lowest level of PA and SB. Dose-response analyses and subgroup analyses were conducted. The I² statistic was used to examine heterogeneity among studies.

RESULTS

We identified 32 observational studies, including 17 cross-sectional studies, 10 case-control studies and five longitudinal studies. PA (highest vs lowest) was inversely associated with risk for any-type CN (n=23 studies) and advanced CN (n=15 studies), with a RR of 0.77 (95% CI=0.71 to 0.83, I²=57.5%) and 0.73 (95% CI=0.63 to 0.82, I²=45.5%), respectively. There was no association between PA and non-advanced CN (n=5 studies). There was an as association between PA and any-type CN in both sexes, and also for the distal colon. We found no dose-response relationship between PA and any-type or advanced CN. Based on three studies identified, SB time (longest vs shortest) was associated with an increased risk of advanced CN (RR=1.24, 95% CI 1.04 to 1.49, I²=14.4%). No publication bias was detected by Begg's test.

CONCLUSION

We report a 23% lower relative risk of any type of CN and a 27% lower risk of advanced CN in people with the highest level of PA compared with those in the lowest.

Energy balance related lifestyle factors and risk of endometrial and colorectal cancer among individuals with lynch syndrome: a systematic review

Lifestyle factors related to energy balance, such as excess body weight, poor diet, and physical inactivity, are associated with risk of sporadic endometrial cancer (EC) and colorectal cancer (CRC). There are limited data on energy balance-related lifestyle factors and EC or CRC risk among individuals with lynch syndrome, who are at extraordinarily higher risk of developing EC or CRC. We conducted a systematic review of evidence related to weight status, weight change, dietary habits, and physical activity on EC and CRC risk among individuals with lynch syndrome. Findings are reported narratively. We searched Medline, EMBASE, CENTRAL, PubMed, and clinicaltrials.gov up to June 14th, 2018. In total, 1060 studies were identified and 16 were included. Three studies were related to EC and 13 to CRC. Overall, evidence suggests that weight status/weight change may not be associated with EC risk and multivitamin and folic-acid supplementation may be associated with decreased EC risk. Early-adulthood overweight/obese weight-status and adulthood weight-gain may be associated with increased CRC risk, whereas multivitamin supplementation, tea and high fruit intake, and physical activity may be associated with decreased CRC risk. Current evidence proposes that recommendations related to weight, some dietary habits, and physical activity recommended for the general public are also relevant to individuals with lynch syndrome. More research is needed, specifically prospective cohorts and randomized controlled trials, to determine if tailored recommendations are needed among individuals with lynch syndrome.

Heterogeneity of Colorectal Cancer Risk Factors by Anatomical Subsite in 10 European Countries: A Multinational Cohort Study

BACKGROUND & AIMS

Colorectal cancer located at different anatomical subsites may have distinct etiologies and risk factors. Previous studies that have examined this hypothesis have yielded inconsistent results, possibly because most studies have been of insufficient size to identify heterogeneous associations with precision.

METHODS

In the European Prospective Investigation into Cancer and Nutrition study, we used multivariable joint Cox proportional hazards models, which accounted for tumors at different anatomical sites (proximal colon, distal colon, and rectum) as competing risks, to examine the relationships between 14 established/suspected lifestyle, anthropometric, and reproductive/menstrual risk factors with colorectal cancer risk. Heterogeneity across sites was tested using Wald tests.

RESULTS

After a median of 14.9 years of follow-up of 521,330 men and women, 6291 colorectal cancer cases occurred. Physical activity was related inversely to proximal colon and distal colon cancer, but not to rectal cancer (P heterogeneity = .03). Height was associated positively with proximal and distal colon cancer only, but not rectal cancer (P heterogeneity = .0001). For men, but not women, heterogeneous relationships were observed for body mass index (P heterogeneity = .008) and waist circumference (P heterogeneity = .03), with weaker positive associations found for rectal cancer, compared with proximal and distal colon cancer. Current smoking was associated with a greater risk of rectal and proximal colon cancer, but not distal colon cancer (P heterogeneity = .05). No heterogeneity by anatomical site was found for alcohol consumption, diabetes, nonsteroidal anti-inflammatory drug use, and reproductive/menstrual factors.

CONCLUSIONS

The relationships between physical activity, anthropometry, and smoking with colorectal cancer risk differed by subsite, supporting the hypothesis that tumors in different anatomical regions may have distinct etiologies.

Physical activity during adolescence and risk of colorectal adenoma later in life: results from the Nurses' Health Study II

Background

Physical activity during adulthood has been consistently associated with lower risk of colorectal cancers, but whether physical activity during adolescence may also play a role in colorectal carcinogenesis is unclear.

Methods

We included 28,250 women in the Nurses’ Health Study II who provided data on physical activity during adolescence (ages 12–22 years) in 1997 and underwent lower bowel endoscopy (1998–2011). We used logistic regression models for clustered data to examine the association between physical activity during adolescence and risk of adenoma later in life.

Results

Physical activity during adolescence was inversely associated with risk of colorectal adenoma (2373 cases), independent of physical activity during adulthood. The multivariable-adjusted odds ratio (OR) of adenoma was 0.89 (95% CI 0.77–1.02; P_trend = 0.03) comparing women with ≥ 72 metabolic equivalent of tasks-hours/week (MET-h/week) to < 21 MET-h/week. Women with high physical activity during both adolescence (≥53.3 MET-h/week) and adulthood (≥23.1 MET-h/week) had significantly lower risk of adenoma (all adenomas: OR 0.76; 95% CI 0.66–0.88; advanced adenoma: OR 0.61; 95% CI 0.45–0.82) compared to women with low physical activity during both stages of life.

Conclusions

Our findings suggest that physical activity during adolescence may lower the risk of colorectal adenoma later in life.

Oxidative stress in biological systems and its relation with pathophysiological functions: the effect of physical activity on cellular redox homeostasis

The body of evidence from the past three decades demonstrates that oxidative stress can be involved in several diseases. This study aims to summarise the current state of knowledge on the association between oxidative stress and the pathogenesis of some characteristic to the biological systems diseases and aging process. This review also presents the effect of physical activity on redox homeostasis. There is strong evidence from studies for participation of reactive oxygen and nitrogen species in pathogenesis of acute and chronic diseases based on animal models and human studies. Elevated levels of pro-oxidants and various markers of the oxidative stress and cells and tissues damage linked with pathogenesis of cancer, atherosclerosis, neurodegenerative diseases hypertension, diabetes mellitus, cardiovascular disease, atherosclerosis, reproductive system diseases, and aging were reported. Evidence confirmed that inflammation contributes widely to multiple chronic diseases and is closely linked with oxidative stress. Regular moderate physical activity regulates oxidative stress enhancing cellular antioxidant defence mechanisms, whereas acute exercise not preceded by training can alter cellular redox homeostasis towards higher level of oxidative stress. Future studies are needed to clarify the multifaceted effects of reactive oxygen/nitrogen species on cells and tissues and to continue study on the biochemical roles of antioxidants and physical activity in prevention of oxidative stress-related tissue injury.

Effect of exercise on colorectal cancer prevention and treatment

In recent years, because of improved cancer screening, detection and treatment modalities, a rapid increase in the population of colorectal and other cancer survivors has been observed. The increasing population has justified the requirement of preventive strategies such as lifestyle modifications with regard to obesity, physical activity, diet and smoking. Physical activity may prevent approximately 15% of the colon cancers. Furthermore, several observational studies have demonstrated the efficacy and dose-dependent and anti-cancer effects of exercise on decreasing the mortality and risk of recurrence before and after the colorectal cancer (CRC) diagnosis. However, the required exercise dose, type and intensity are yet unclear. The results of randomised prospective studies are expected to determine the optimal amount, type and intensity of exercise and formulate the most appropriate exercise plan and guidelines, according to the requirements and comorbidities of the patients. In addition, recent studies have focused on the molecular and genetic mechanisms underlying the effect of physical activity on disease outcomes and recurrence rates. This review aimed to investigate the effects of physical activity and the biological basis of these effects in preventing the risk and recurrence of CRC and decreasing the hazards of cancer and cancer treatment.

Colon cancer stem cells: Potential target for the treatment of colorectal cancer

Despite incessant research, colon cancer still is one of the most common causes of fatalities in both men and women worldwide. Also, nearly 50% of patients with colorectal cancer show tumor recurrence. Recent investigations have highlighted the involvement of colon cancer stem cells (CCSCs) in cancer relapse and chemoresistance. CCSCs deliver a significant protumorigenic niche through persistent overexpression of self-renewal capabilities. Moreover, CSCs cross network with stromal cells, immune infiltrates, and cyotokine-chemokine, which potentiate their aggressive proliferative potential. Targeting CCSCs through small molecule inhibitors, miRNAs, and monoclonal antibodies (mAbs) in in vivo studies has generated compelling evidence for the effectiveness of these various treatments. This review effectively compiles the role of CCSC surface markers and dysregulated and/or upregulated pathways in the pathogenesis of colorectal cancer that can be used to target CCSCs for effective colorectal cancer treatment.

Lifestyle and cancer-a joint pairwise association of lifestyle habits with subsequent cancer diagnosis

BACKGROUND

Unhealthy behaviours increase cancer risk. However, lifestyle habits co-occur and their joint association with cancer is not known.

METHODS

A survey among midlife employees included data on lifestyle habits and covariates (N = 8960, response rate 67%, 80% women). The joint variables of lifestyle habits were prospectively linked with register data on cancer diagnosis (mean follow-up time 12.1 years). Cox proportional hazard model was used to calculate hazard ratios (HR), and their 95% confidence intervals.

RESULTS

Smoking was associated with subsequent cancer risk and the association was strengthened by inactivity (HR 1.94, 1.46-2.59) and unhealthy diet (HR 1.92, 1.43-2.57). Smoking combined with both low (HR 1.70, 1.19-2.41) and moderate (HR 1.68, 1.27-2.23) alcohol consumption was also associated with increased cancer risk, as was unhealthy diet combined with moderate alcohol consumption (HR 1.55, 1.17-2.06) and inactivity (HR 1.44, 1.10-1.88). Inactivity combined with either low (HR 1.44, 1.06-1.96) or moderate (HR 1.47, 1.11-1.95) alcohol use was associated with subsequent cancer risk.

CONCLUSIONS

Key unhealthy behaviours have additive effects. Preventive measures should be targeted to especially smokers and those having several adverse lifestyle habits.

Physical Activity and Colorectal Cancer Risk by Sex, Race/Ethnicity, and Subsite: The Multiethnic Cohort Study

Physical activity has been associated with a lower risk of colorectal cancer. However, data is lacking on whether the association is consistent between sexes and across different races/ethnicities and anatomic subsites of tumors. We analyzed data from the Multiethnic Cohort in Hawaii and California, consisting of mostly African Americans, Native Hawaiians, Japanese Americans, Latinos, and whites ages 45-75 years at recruitment. During a mean follow-up of 16.8 years, 4,430 invasive adenocarcinoma cases of the colorectum were identified among 172,502 eligible participants. Cox proportional hazards models were used to estimate the HR and 95% confidence interval (CI). The multivariate-adjusted HR (95% CI) for the highest versus lowest quintiles of physical activity (metabolic equivalent hours of moderate or vigorous activities per day) was 0.76 (0.66-0.87) in men (P _trend < 0.001) and 0.94 (0.80-1.11) in women (P _trend = 0.53, P _{heterogeneity by sex} = 0.07). Sleeping and sitting hours were not associated with colorectal cancer risk both in men and women. In men, the inverse association was statistically significant among African Americans and Japanese Americans, for right colon and rectal cancer, and in all body mass index groups, although heterogeneity tests were not significant across race/ethnicity or anatomic subsite of tumors. The findings confirm the inverse association between physical activity and colorectal cancer, which appears to be stronger in men, and suggest possible differences in the strength of the association by race/ethnicity and anatomic subsite of tumors.

Physical Activity and Gastrointestinal Cancer Risk: A Review

Introduction: Western lifestyle characterized by increased consumption of red meat, fat, processed food, smoking, alcohol drinking, lower consumption of vegetables and physical inactivity has been associated with a higher gastrointestinal cancer risk. Digestive system cancers are diagnosed at late stages when they show poor response to treatment and are associated with a high mortality rate. Colorectal, gastric, esophageal and pancreatic cancers are among the most common cancers worldwide. Studies show that more than 50% of gastrointestinal cancers develop as a result of inappropriate lifestyle. An inverse association between physical activity and many chronic diseases has been proved so far. However, the association between physical activity and some gastrointestinal cancers is still controversial. This study was aimed to determine the association between physical activity and gastrointestinal cancers risk.

Methods: We conducted a comprehensive search of English and Persian databases from February 2007 till December 2017, for studies investigating the association of physical activity and risk of gastrointestinal cancers. Finally, after reading full text of articles, 123 studies were included.

Results: Physical activity can be helpful in reducing the risk of gastrointestinal cancer, especially colon and pancreatic cancers. The risk reduction is not similar for different types of gastrointestinal cancers and also among males and females.

Conclusion: Different types of physical activity are associated with a lower risk of gastrointestinal cancer. However, it is unknown which type and intensity of physical activity are associated with a protective effect against gastro-intestinal cancer.

Anthropometric characteristics, physical activity and risk of hematological malignancies: A systematic review and meta-analysis of cohort studies

Overweight/obesity, adult attained height and physical activity are possible risk factors for hematological malignancies. This meta-analysis aims to evaluate the associations between these factors and hematological cancer risk in adults. Eligible cohort studies were sought in PubMed up to May 31, 2016; overall, 44 studies were included in the present analyses. Pooled relative risk estimates were calculated using random-effects models; separate analyses were conducted for non-Hodgkin lymphoma (NHL) and subtypes (diffuse large B-cell lymphoma, DLBCL; follicular cell lymphoma; small lymphocytic lymphoma/chronic lymphocytic leukemia, SLL/CLL), Hodgkin lymphoma (HL), multiple myeloma (MM), leukemia and subtypes (acute lymphoblastic leukemia, acute myeloid leukemia, AML). Obesity was associated with increased risk of NHL, HL, MM, leukemia overall and AML in both sexes, as well as with higher DLBCL risk in women; the dose-response meta-regression analysis confirmed these associations. Less pronounced effects were observed regarding overweight, as it was associated with increased MM risk in both sexes, NHL risk in males, DLBCL and overall leukemia risk in females. Taller men presented with significantly higher risk of NHL and taller women were affected by higher risk of NHL, DLBCL, FL, CLL/SLL, MM, leukemia and AML. On the other hand, physical activity and abdominal fatness were not associated with the risk of hematological malignancies. In conclusion, this meta-analysis highlights the pivotal role of anthropometric measures in shaping the risk of hematological malignancies in adults. Additional, well-designed studies stemming from all the continents are needed for the further substantiation and generalization of the results.

Prevalence of and Risk Factors for Colorectal Neoplasia in Asymptomatic Young Adults (20-39 Years Old)

BACKGROUND & AIMS

The incidence of colorectal cancer is increasing among persons 50 years old or younger. However, data on the epidemiology of young-onset colorectal neoplasia (CRN) are limited. Although some studies have investigated the epidemiology of CRN in persons younger than 50 years, most have focused on persons 40 years or older. We evaluated the prevalence of and risk factors for CRN in adults younger than 40 years.

METHODS

We performed a cross-sectional analysis of 72,356 asymptomatic individuals, 20-39 years old, who underwent colonoscopies as participants in the Kangbuk Samsung Health Study in South Korea, from August 2004 through December 2015. Data on medical history and health-related behavior were collected from self-administered questionnaires. Patients were divided into groups based on age (20-29 years, n = 7340 or 30-39 years, n = 65,016), and χ² tests were used to compare categorical variables between groups. A multivariate logistic regression model was used to assess the risk factors for overall and advanced CRN.

RESULTS

The prevalence of overall CRN in group of 20-29 years was 5.9% and in the group of 30-39 years was 9.5% (P < .001); prevalence values for advanced CRN were 0.6% and 0.9%, respectively (P = .005). In the group of 30-39 years, age, smoking, alcohol intake, obesity, and abdominal obesity were independent risk factors for overall and advanced CRN. Additionally, male sex and metabolic syndrome were independent risk factors for overall CRN, whereas regular exercise reduced risk of overall CRN. Even in the 20-29 years group, obesity, abdominal obesity, and increased levels of triglycerides were independent risk factors for overall and advanced CRN, whereas age, increased blood pressure, and increased fasting blood glucose level were independent risk factors for overall CRN.

CONCLUSION

In a retrospective analysis of 72,356 asymptomatic persons under 40 years of age evaluated by colonoscopy in Korea, we found modifiable factors, such as smoking, alcohol intake, obesity, and metabolic syndrome, to be significant risk factors for CRN-even in persons of 20-39 years old. Colorectal cancer screening strategies should consider these risk factors.

Body Mass Index and Long-Term Outcomes in Patients With Colorectal Cancer

Background: The association between body mass index (BMI) and colorectal cancer is unique. There are several patient- and tumor-related factors that affect this and associations are not entirely clear. The primary aim of this study is to examine the association between BMI and survival after colorectal cancer diagnosis.

Methods: Among 26,908 Mayo Clinic patients diagnosed with colorectal cancer between 1972 and 2017, 3,799 patients had information on BMI within 6 months prior to cancer diagnosis. Multivariable Cox regression models were used to assess the differences in overall survival between BMI groups in each cancer stage, controlling for age, gender, year of diagnosis, and cancer location. The impact of change of BMI at 30, 60, and 90 days on survival afterwards were also analyzed.

Results: Among 3,799 patients included in the study, there were 29% normal weight, 2% underweight, 36% overweight, and 33% obese patients. With all stages combined together, the overall 5-years survival rates for underweight, normal weight, overweight, and obese patients were 33, 56, 60, and 65%, respectively (p < 0.001). The results show that, the difference in overall survival was not statistically significant when underweight, overweight, and obese patients were compared to normal weight patients in stage 1 and stage 2, although there was a trend that overweight patients had better survival than normal weight group in stage 2 cancer patients (HR = 0.8, p = 0.086). In stage 3 and 4 patients combined, underweight group demonstrated a significant disadvantage (HR = 1.96, p = 0.007) for overall survival compared to the normal weight group. Additionally, post-diagnosis BMI drop more than 10% from either a previous time (HR = 1.88, p = 0.002) or pre-diagnosis time (HR = 1.61, p < 0.001) was associated with worse overall survival after adjusting for baseline variables.

Conclusions: BMI is an important consideration in patients with colorectal cancer. Outcomes are stage-dependent where in some situations obesity maybe an advantage. More importantly, being underweight is a significant negative predictor of outcome. The impact of drop in BMI or weight, on survival of CRC patients, needs to be studied further since this is potentially an actionable variable and a dynamic biomarker that may help improve outcome in these patients.

Setting larger session duration goals is associated with greater future physical activity

Many national (US) and International guidelines for physical activity provide guidance that under-active and sedentary adults can begin by accumulating moderate-to-vigorous physical activity (MVPA) in bouts as brief as 10 minutes. This guidance fits well with Goal Setting theory in that goals should be realistic and achievable, and is also consistent with Social Cognitive theory since achieving small goals should boost self-efficacy and thus, encourage continued physical activity. In contrast, Behavioral Economics might suggest that fewer, longer bouts would be more conducive to the adoption of physical activity due to the costs incurred with each separate bout of MVPA. This paper examines patterns of MVPA adoption among a sample of under-active adults from the perspective of goal setting theory and behavioral economics to explore specific strategies to help people who are in the early stages of PA activity adoption. Under-active men and women (N = 225; mean age = 46 ± 10; mean BMI = 28 ± 4.48) who enrolled in a PA intervention participated in a single goal setting session at enrollment. Participants were encouraged to set realistic goals and to increase their activity to meet national recommendations (150 minutes/week of moderate to vigorous physical activity [MVPA]) by the 6-month follow up. This process included identifying a specific frequency goal (days/week) and session duration goal (minutes/day). At baseline, participants reported average weekly MVPA of 14.59 min (± 24), which increased to an average of 140.52 (± 143.55) at 6 months. MVPA goals at baseline averaged 33.24 min/day (± 18.08) and 3.85 days/week (± 1.31). Analyses showed that longer session duration goals set at baseline were associated with more weekly minutes of MVPA at 6 months (b = 1.26, SE = 0.58, t = 2.17, p = 0.03). There was no significant association between goals for number of days per week (frequency) or total minutes of weekly MVPA (minutes x frequency) and MVPA at 6 months. Widely promoted guidelines for uptake of physical activity recommend accumulating physical activity in bouts as short as 10 minutes. This recommendation may ultimately hinder the adoption of physical activity among under-active and sedentary individuals. For the purposes of behavioral adoption of MVPA, more ambitious session duration goals appear to result in higher levels of physical activity participation.

Healthy Lifestyle Factors Associated With Lower Risk of Colorectal Cancer Irrespective of Genetic Risk

BACKGROUND & AIMS

The combined effects of healthy lifestyle factors on colorectal cancer (CRC) risk are unclear. We aimed to develop a healthy lifestyle score, to investigate the joint effects of modifiable lifestyle factors on reduction of CRC risk and determine whether associations differ with genetic risk.

METHODS

We collected data from a large population-based case-control study in Germany and used multiple logistic regression analyses to examine associations between the healthy lifestyle score (derived from 5 modifiable lifestyle factors: smoking, alcohol consumption, diet, physical activity, and body fatness) and CRC risk. We created a genetic risk score, based on 53 risk variants, to investigate the association of the healthy lifestyle score and risk of CRC, stratified by genetic risk.

RESULTS

We included 4092 patients with CRC and 3032 individuals without CRC (controls) in our analysis. In adjusted models, compared with participants with 0 or 1 healthy lifestyle factor, participants with 2 (odds ratio [OR] 0.85; 95% confidence interval [CI] 0.67-1.06), 3 (OR 0.62; 95% CI 0.50-0.77), 4 (OR 0.53; 95% CI 0.42-0.66), or 5 (OR 0.33; 95% CI 0.26-0.43) healthy lifestyle factors had increasingly lower risks of CRC (P trend <.0001). We found no differences among subgroups stratified by genetic risk score, history of colonoscopy, or family history of CRC. Overall, 45% of CRC cases (95% CI 34%-53%) could be attributed to nonadherence to all 5 healthy lifestyle behaviors.

CONCLUSIONS

In a large population-based case-control study, we identified a combination of lifestyle factors that appears to reduce risk of CRC, regardless of the patient's genetic profile. These results reinforce the importance of primary prevention of CRC.