Sedentary Behaviour and Cancer

Leisure time television watching, computer use and risks of breast, colorectal and prostate cancer: A Mendelian randomisation analysis

BACKGROUND

Sedentary behaviours have been associated with increased risks of some common cancers in epidemiological studies; however, it is unclear if these associations are causal.

METHODS

We used univariable and multivariable two-sample Mendelian randomisation (MR) to examine potential causal relationships between sedentary behaviours and risks of breast, colorectal and prostate cancer. Genetic variants associated with self-reported leisure television watching and computer use were identified from a recent genome-wide association study (GWAS). Data related to cancer risk were obtained from cancer GWAS consortia. A series of sensitivity analyses were applied to examine the robustness of the results to the presence of confounding.

RESULTS

A 1-standard deviation (SD: 1.5 h/day) increment in hours of television watching increased risk of breast cancer (OR per 1-SD: 1.15, 95% confidence interval [CI]: 1.05-1.26) and colorectal cancer (OR per 1-SD: 1.32, 95% CI: 1.16-1.49) while there was little evidence of an association for prostate cancer risk (OR per 1-SD: 0.94, 95% CI: 0.84-1.06). After adjusting for years of education, the effect estimates for television watching were attenuated (breast cancer, OR per 1-SD: 1.08, 95% CI: 0.92-1.27; colorectal cancer, OR per 1-SD: 1.08, 95% CI: 0.90-1.31). Post hoc analyses showed that years of education might have a possible confounding and mediating role in the association between television watching with breast and colorectal cancer. Consistent results were observed for each cancer site according to sex (colorectal cancer), anatomical subsites and cancer subtypes. There was little evidence of associations between genetically predicted computer use and cancer risk.

CONCLUSIONS

Our univariable analysis identified some positive associations between hours of television watching and risks of breast and colorectal cancer. However, further adjustment for additional lifestyle factors especially years of education attenuated these results. Future studies using objective measures of exposure can provide new insights into the possible role of sedentary behaviour in cancer development.

Leisure time sedentary behaviour and risks of breast, colorectal, and prostate cancer: A Mendelian randomization analysis

Sedentary behaviours have been associated with increased risks of some common cancers in epidemiological studies; however, it is unclear if these associations are causal. We examined potential causal associations between self-reported leisure television watching and computer use and risks of breast, colorectal, and prostate cancer using a two-sample Mendelian randomization framework. Genetic variants were identified from a recent genome-wide association study (GWAS). Cancer data were obtained from cancer GWAS consortia. Additional sensitivity analyses were applied to examine the robustness of the results. A 1-standard deviation increment in hours of television watching increased risk of breast (OR: 1.15, 95% confidence interval [CI]: 1.05,1.26) and colorectal cancer (OR: 1.32, 95%CI: 1.16,1.49) with little evidence of an association for prostate cancer risk. In multivariable models adjusted for years of education, the effect estimates for television watching were attenuated (breast cancer, OR: 1.08, 95%CI: 0.92,1.27; colorectal cancer, OR: 1.08, 95%CI: 0.90,1.31). Post-hoc analyses showed that years of education might have a possible confounding and mediating role in the association between television watching with breast and colorectal cancer. Consistent results were observed by sex (colorectal cancer), anatomical subsites, and cancer subtypes. There was little evidence of associations between computer use and cancer risk. We found evidence of positive associations between hours of television watching and risks of breast and colorectal cancer. However, these findings should be interpreted cautiously given the complex role of education. Future studies using objective measures of exposure can provide new insights into the possible role of sedentary behaviour in cancer development.

Novelty and impact

Evidence from observational studies that examined associations between sedentary behaviours and common cancers is mixed and causality is uncertain. In our Mendelian randomization analyses, higher levels of leisure television watching were found to increase the risks of breast and colorectal cancer, suggesting that the that the promotion of lowering sedentary behaviour time could be an effective strategy in the primary prevention of these commonly diagnosed cancers.

Article category

Cancer Epidemiology.

Physical activity, sedentary time and breast cancer risk: a Mendelian randomisation study

OBJECTIVES

Physical inactivity and sedentary behaviour are associated with higher breast cancer risk in observational studies, but ascribing causality is difficult. Mendelian randomisation (MR) assesses causality by simulating randomised trial groups using genotype. We assessed whether lifelong physical activity or sedentary time, assessed using genotype, may be causally associated with breast cancer risk overall, pre/post-menopause, and by case-groups defined by tumour characteristics.

METHODS

We performed two-sample inverse-variance-weighted MR using individual-level Breast Cancer Association Consortium case-control data from 130 957 European-ancestry women (69 838 invasive cases), and published UK Biobank data (n=91 105-377 234). Genetic instruments were single nucleotide polymorphisms (SNPs) associated in UK Biobank with wrist-worn accelerometer-measured overall physical activity (nsnps=5) or sedentary time (nsnps=6), or accelerometer-measured (nsnps=1) or self-reported (nsnps=5) vigorous physical activity.

RESULTS

Greater genetically-predicted overall activity was associated with lower breast cancer overall risk (OR=0.59; 95% confidence interval (CI) 0.42 to 0.83 per-standard deviation (SD;~8 milligravities acceleration)) and for most case-groups. Genetically-predicted vigorous activity was associated with lower risk of pre/perimenopausal breast cancer (OR=0.62; 95% CI 0.45 to 0.87,≥3 vs. 0 self-reported days/week), with consistent estimates for most case-groups. Greater genetically-predicted sedentary time was associated with higher hormone-receptor-negative tumour risk (OR=1.77; 95% CI 1.07 to 2.92 per-SD (~7% time spent sedentary)), with elevated estimates for most case-groups. Results were robust to sensitivity analyses examining pleiotropy (including weighted-median-MR, MR-Egger).

CONCLUSION

Our study provides strong evidence that greater overall physical activity, greater vigorous activity, and lower sedentary time are likely to reduce breast cancer risk. More widespread adoption of active lifestyles may reduce the burden from the most common cancer in women.

Substituting bouts of sedentary behavior with physical activity: adopting positive lifestyle choices in people with a history of cancer

Purpose

To determine in people with a history of cancer, whether substituting sitting time with other daily activities (i.e., sleeping, walking, moderate and vigorous physical activity) was associated with changes in waist circumference (WC), an important surrogate marker of cardiometabolic risk.

Methods

Cross-sectional analyses from the Atlantic Partnership for Tomorrow’s Health (Atlantic PATH) cohort was conducted using isotemporal substitution models to explore the associations of substituting sedentary time, physical activity behavior (International Physical Activity Questionnaire), or sleep (Pittsburgh Sleep Quality Index) with changes in WC. Analyses were conducted using sex-specific WC classifications.

Results

In 3,684 people with a history of cancer [mean age (SD) 58.2 (7.3) years; BMI 28.9 (5.2) kg m⁻²; 71% female], reallocating 10 min of sleep or sedentary time for 10 min of walking was associated with lower WC in women (p < 0.01). In men, PA intensity appeared to be more strongly associated with a reduced WC. Replacing 10 min of sedentary time with 10 min of moderate or vigorous PA and replacing 10 min of sleep with moderate PA were associated with a significantly reduced WC (p < 0.001). The largest effect was when 10 min of moderate PA was replaced with vigorous PA, a reduction in WC (p < 0.01) was evident.

Conclusion

For people with a history of cancer, adopting small but positive changes in lifestyle behaviors could help reduce WC and potentially offset negative health-related outcomes associated with higher WC. Further research is required to examine whether such an intervention may be acceptable and manageable among this population.

Physical health effects of sedentary behaviour on adults with an intellectual disability: A scoping review

This literature review was designed to establish the effects of sedentary behaviour on the physical health of adults with an intellectual disability. Sedentary behaviour is defined as any waking behaviour characterized by an energy expenditure of ≤1.5 METs while in a sitting, lying or reclining posture. An extensive search was executed in six databases: EMBASE, Medline, CINAHL, PsycINFO, ASSIA and Web of Science. Following screening, 18 articles remained for inclusion in the review. A thematic analysis using the Braun and Clarke six step process resulted in the identification of seven broad health areas. Studies showed a prevalence of obesity, multimorbidity and metabolic syndrome as well as elevated levels of sedentary behaviour in adults with an intellectual disability. This literature review demonstrated that sedentary behaviour could be a contributor to the poor health which is common in adults with an intellectual disability. However to date the body of evidence does not confirm a cause-and-effect relationship.

Sedentary behavior and cancer-an umbrella review and meta-analysis

Several systematic reviews and meta-analyses have summarized the association between sedentary behavior (SB) and cancer. However, the level of evidence and the potential for risk of bias remains unclear. This umbrella review summarized the current data on SB in relation to cancer incidence and mortality, with a particular emphasis on assessing the risk of bias. We searched PubMed, Web of Science and Cochrane Database for systematic reviews and meta-analyses on the association between SB and cancer incidence and mortality. We also searched for recent observational studies not yet included in existing meta-analyses. We re-calculated summary risk estimates for cancer incidence and mortality using random effects models. We included 14 meta-analyses covering 17 different cancer sites from 77 original studies. We found that high SB levels increase the risk for developing ovarian, endometrial, colon, breast, prostate, and rectal cancers, with relative risks of 1.29 (95% confidence interval (CI) = 1.08-1.56), 1.29 (95% CI = 1.16-1.45), 1.25 (95% CI = 1.16-1.33), 1.08 (95% CI = 1.04-1.11), 1.08 (95% CI = 1.00-1.17), and 1.07 (95% CI = 1.01-1.12), respectively. Also, we found an increased risk of cancer mortality of 1.18 (95% CI = 1.09-1.26). Most associations between SB and specific cancer sites were supported by a "suggestive" level of evidence. High levels of SB are associated with increased risk of several types of cancer and increased cancer mortality risk.

Translating 2019 ACSM Cancer Exercise Recommendations for a Physiatric Practice: Derived Recommendations from an International Expert Panel

In 2018, the American College of Sports Medicine (ACSM) reconvened an international, multi-disciplinary group of professionals to review pertinent published literature on exercise for people with cancer. The 2018 roundtable resulted in the publication of three articles in 2019. The three articles serve as an important update to the original ACSM Roundtable on Cancer, which convened in 2010. Although the focus of the three 2019 articles is on exercise, which is only one part of comprehensive cancer rehabilitation, the evidence presented in the 2019 ACSM articles has direct implications for physiatrists and other rehabilitation professionals who care for people with cancer. As such, the narrative review presented here has two primary objectives. First, we summarize the evidence within the three ACSM articles and interpret it within a familiar rehabilitation framework, namely the Dietz model of Cancer Rehabilitation, in order to facilitate implementation broadly within rehabilitation practice. Second, via expert consensus, we have tabulated relevant exercise recommendations for specific cancer populations at different points in the cancer care continuum and translated them into text, tables, and figures for ease of reference. Notably, the authors of this article are members of the Cancer Rehabilitation Physician Consortium (CRPC), a group of physicians who subspecialize in cancer rehabilitation medicine (CRM).

Sedentary behaviour in relation to ovarian cancer risk: a systematic review and meta-analysis

Sedentary behaviour is an emerging risk factor for several site-specific cancers. Ovarian cancers are often detected at late disease stages and the role of sedentary behaviour as a modifiable risk factor potentially contributing to ovarian cancer risk has not been extensively examined. We systematically searched relevant databases from inception to February 2020 for eligible publications dealing with sedentary behaviour in relation to ovarian cancer risk. We conducted a systematic review and meta-analysis, calculating summary relative risks (RR) and 95% confidence intervals (CI) using a random-effects model. We calculated the E-Value, a sensitivity analysis for unmeasured confounding. We tested for publication bias and heterogeneity. Seven studies (three prospective cohort studies and four case–control studies) including 2060 ovarian cancer cases were analysed. Comparing highest versus lowest levels of sedentary behaviour, the data indicated a statistically significant increase in the risk of ovarian cancer in relation to prolonged sitting time (RR = 1.29, 95% CI = 1.07–1.57). Sub-analyses of prospective cohort studies (RR = 1.33, 95% CI = 0.92–1.93) and case–control studies (RR = 1.28, 95% CI = 0.98–1.68) showed statistically non-significant results. Sensitivity analysis showed that an unmeasured confounder would need to be related to sedentary behaviour and ovarian cancer with a RR of 1.90 to fully explain away the observed RR of 1.29. Our analyses showed a statistically significant positive association between sedentary behaviour and ovarian cancer risk.

American Cancer Society guideline for diet and physical activity for cancer prevention

The American Cancer Society (ACS) publishes the Diet and Physical Activity Guideline to serve as a foundation for its communication, policy, and community strategies and, ultimately, to affect dietary and physical activity patterns among Americans. This guideline is developed by a national panel of experts in cancer research, prevention, epidemiology, public health, and policy, and reflects the most current scientific evidence related to dietary and activity patterns and cancer risk. The ACS guideline focuses on recommendations for individual choices regarding diet and physical activity patterns, but those choices occur within a community context that either facilitates or creates barriers to healthy behaviors. Therefore, this committee presents recommendations for community action to accompany the 4 recommendations for individual choices to reduce cancer risk. These recommendations for community action recognize that a supportive social and physical environment is indispensable if individuals at all levels of society are to have genuine opportunities to choose healthy behaviors. This 2020 ACS guideline is consistent with guidelines from the American Heart Association and the American Diabetes Association for the prevention of coronary heart disease and diabetes as well as for general health promotion, as defined by the 2015 to 2020 Dietary Guidelines for Americans and the 2018 Physical Activity Guidelines for Americans.

The Change of Interleukin-6 Level-Related Genes and Pathways Induced by Exercise in Sedentary Individuals

Sedentary behavior increases the risk of many chronic disorders, in addition, these chronic diseases are associated with elevated markers interleukin-6 (IL-6). Increasing evidence indicates that physical activity can prevent chronic inflammatory disease. However, the effect of exercise on sedentary individuals with disparate basal serum IL-6 level was not well elucidated. In this study, the gene expression profile of GES12384 was downloaded from the Gene Expression Omnibus (GEO) database. This data set contained 12 sedentary middle-aged men (6 high IL-6 and 6 low IL-6 level), and their blood samples were taken in the pre-exercise period and at the end of 24 weeks of exercise. The differentially expressed genes (DEGs) of 24 weeks group were identified, followed by functional enrichment analysis. Subsequently, protein-protein interaction (PPI) network and transcription factors (TFs)-DEGs network were constructed. A total of 193 DEGs were identified between high and low IL-6 level in the 24 weeks group. Functional enrichment analysis showed that DEGs were mainly involved in African trypanosomiasis pathway. PPI network revealed that the hub genes included C-C motif chemokine receptor 7 (CCR7), hemoglobin subunit delta (HBD), and interferon gamma (IFNG). Subnetworks analysis indicated that these genes were relevant to immune response, and participated in African trypanosomiasis pathway. The TF targets network found that myocyte enhancer factor 2A (MEF2A) was a key regulatory factor. In conclusion, the inflammation-related genes (CCR7, HBD, and IFNG) in sedentary individuals could be affected by exercise, and the identified DEGs and TFs in this study promoted our understanding of exercise inhibited the development of chronic disease. [Figure: see text].

Motivational interviewing added to oncology rehabilitation did not improve moderate-intensity physical activity in cancer survivors: a randomised trial

QUESTION

Does adding weekly, physiotherapist-delivered motivational interviewing to outpatient oncology rehabilitation for cancer survivors increase physical activity levels and improve physical and psychosocial outcomes that are typically impaired in this cohort?

DESIGN

Randomised controlled trial with blinded outcome assessment, concealed allocation and intention-to-treat analysis.

PARTICIPANTS

A heterogeneous sample of 46 cancer survivors (n=29 female; mean age 59 years) participating in a public outpatient oncology rehabilitation program.

INTERVENTION

Participants were randomly allocated to receive oncology rehabilitation (n=24) or oncology rehabilitation with motivational interviewing delivered once weekly for 7 weeks via telephone by a physiotherapist (n=22).

OUTCOME MEASURES

The primary outcome was amount of physical activity of at least moderate intensity completed in 10-minute bouts, measured by an accelerometer worn continuously for 1 week. Secondary outcomes included other measures of physical activity, sedentary behaviour, physical function, psychosocial function, and quality of life.

RESULTS

When added to oncology rehabilitation, motivational interviewing caused no appreciable increase in the amount of moderate-intensity physical activity (MD -1.2 minutes/day, 95% CI -2.5 to 0.02). Among many secondary outcomes, the only statistically significant result was a small effect on nausea, which probably represents a Type I error. However, several secondary outcomes related to lower-intensity physical activity had non-significant confidence intervals that included large effects such as: sedentary time (SMD -0.67, 95% CI -1.32 to 0.02), light-intensity physical activity (SMD 0.56, 95% CI -0.12 to 1.21) and daily step count (SMD 0.37, 95% CI -0.30 to 1.02).

CONCLUSION

Adding motivational interviewing to oncology rehabilitation did not increase moderate-intensity physical activity. Favourable trends on measures of lower-intensity physical activity suggest that motivational interviewing should be further investigated for its effects on reducing sedentary time and improving light-intensity physical activity for cancer survivors participating in rehabilitation.

TRIAL REGISTRATION

ANZCTR 12616001079437. [Dennett AM, Shields N, Peiris CL, Prendergast LA, O'Halloran PD, Parente P, Taylor NF (2018) Motivational interviewing added to oncology rehabilitation did not improve moderate-intensity physical activity in cancer survivors: a randomised trial. Journal of Physiotherapy 64: 255-263].