Modifying modularity: aerobic exercise improves functional connectivity in breast cancer survivors

IntroductionAerobic exercise has been shown to improve cancer-associated cognitive decline (CACD) in breast cancer survivors (BCS), and recent findings suggest that one mechanism by which exercise may reduce cognitive decline is through alteration of the brain's functional organization. Many cognitive abilities and measures of functional brain organization change with age and disease, typically reflected in cognitive decline and reduced differentiation of brain networks, or “modularity.” Although previous research has identified associations between lifestyle interventions, such as exercise, and increased modularity, no studies have examined these relationships in cancer populations. The primary aim of this study was to investigate the preliminary effects of a 12-week aerobic exercise program on changes in brain network modularity in BCS. As a secondary aim, we explored correlations between changes in modularity with moderate-to-vigorous physical activity (MVPA) and cognitive function. Data were exploratory and used for hypothesis generation for a future, larger study.MethodsParticipants included a subsample of 10 BCS (M age = 65.9 ± 9.3 years) from a larger pilot study (N = 30 BCS) who were randomized to a 12-week aerobic exercise program (AE) or usual care (UC). The present study collected brain magnetic resonance imaging, Actigraph accelerometry, and cognitive task performance at baseline and 3-month follow-up (i.e., post-intervention; n = 4 AE, n = 6 UC). Intervention effects on modularity, MVPA, and cognition were quantified as magnitude of change between groups (Cohen's d). Changes in modularity were further explored via paired t-tests within groups. Associations between changes in modularity, MVPA, and cognitive performance were explored using Spearman's correlations.ResultsThe magnitude of changes in modularity between groups were small-to-moderate and favored the AE group (d = 0.23 to d = 0.67 across thresholds). Paired t-tests revealed a significant increase in modularity in the AE group from baseline to 3-month follow-up (t = 3.08, p = 0.03, d = 1.17), but not in the UC group. The correlation between changes in MVPA and changes in modularity were not statistically significant (r = 0.36, p = 0.39), and correlations between modularity and cognitive performance yielded mixed effects by cognitive domain.DiscussionFindings suggest that aerobic exercise may influence functional brain network organization and cognition in BCS. These data warrant further investigation in larger exercise trials

Prevalence of healthy behaviors among cancer survivors in the United States: How far have we come?

Background: The 16.9 million cancer survivors in the United States are at increased risk for comorbidities and recurrence. However, this risk may be attenuated by a healthy lifestyle. This study describes health behaviors by cancer history to inform behavior change priorities. Methods: We analyzed 2013–2017 data from the National Health Interview Survey. There were 164,692 adults, of whom 12,648 reported a cancer history. We calculated prevalence of smoking, physical activity, alcohol consumption, body mass index (BMI), and sleep duration by cancer history, age, and cancer site. We conducted logistic regression to determine odds of meeting lifestyle recommendations by cancer history. Results: Overall, those with a cancer history were less likely to report current smoking (14.1% vs. 16.8%) and moderate/heavy drinking (18.8% vs. 21.9%) than those without a cancer history. However, a lower percentage of cancer survivors met physical activity guidelines (14.2% vs. 21.1%) or reported a healthy BMI (31.6% vs. 34.7%) compared with those without a cancer history. Cancer survivors were more likely to report excessive sleep (6.8% vs. 3.6%). In adjusted logistic regression, survivors were more likely to meet recommendations on smoking, physical activity, and BMI but were less likely to meet alcohol recommendations; meeting sleep recommendations did not differ by cancer history. Conclusions: While cancer survivors had lower prevalence of smoking and moderate/heavy drinking, they also had lower prevalence of physical activity and healthy BMI, and reported longer sleep duration. Regression analyses suggested survivors only showed poorer behaviors for alcohol. Impact: Targeted health promotion interventions among cancer survivors are needed

Provider discussion about lifestyle by cancer history: A nationally representative survey.

BACKGROUND: Providers are uniquely positioned to encourage health promoting behaviors, particularly among cancer survivors where patients develop trust in providers. METHODS: We utilized the National Health Interview Survey to identify adults who reported a visit to a provider in the prior year (44,385 individuals with no cancer history and 4,792 cancer survivors), and reported prevalence of provider discussions on weight loss, physical activity, diet, and smoking. We used generalized linear mixed models to examine predicted prevalence of a provider lifestyle discussions by cancer history overall, and among those who do not meet body mass index (BMI), activity, or smoking guidelines. RESULTS: Among those with a BMI 25-<60 kg/m(2), 9.2% of those with a cancer history and 11.6% of those without a cancer history reported being told to participate in a weight loss program (p<0.001). Overall, 31.7% of cancer survivors and 35.3% of those with no cancer history were told to increase their physical activity (p<0.001). Only 27.6% of cancer survivors and 32.2% of those with no cancer history reported having a general discussion of diet (p<0.001). Among smokers 67.3% of cancer survivors and 69.9% of those with no cancer history reported counseling on smoking (p=0.309). CONCLUSIONS: Fewer cancer survivors, who are at increased risk for health complications, are reporting provider discussions about critical lifestyle issues than those with no cancer history. IMPACT: Our nationally representative results suggest that providers are missing an opportunity for influencing patient lifestyle factors, which could lead to mitigation of late and long-term effects of treatment

Physical activity and cognitive function: A comparison of rural and urban breast cancer survivors

Purpose Increasing evidence suggests rural breast cancer survivors (BCS) may experience greater burden in symptoms known to be associated with cancer-associated cognitive decline (CACD). Yet, little is known about CACD in rural BCS. This study (1) examined differences in cognitive function, moderate-to-vigorous physical activity (MVPA), and other CACD correlates and (2) tested the effects of MVPA on cognitive function in rural versus urban BCS. Methods Rural and urban BCS (N = 80), matched on age, education, and time since diagnosis from a larger study, completed cognitive tasks assessing processing speed (Trails-B, Mazes, Task-Switch) and working memory (spatial working memory) and questionnaires assessing subjective memory impairment (SMI), MVPA, and CACD correlates (i.e., sleep quality, fatigue, anxiety/depression). Some participants (n = 62) wore an accelerometer to objectively estimate MVPA. Multiple linear regression and multivariate analysis of covariance were used to test study aims. Results Rural BCS (n = 40, M = 61.1±8.4 years-old) performed significantly slower on Trails-B (p0.28). Regression models did not reveal a significant interaction between MVPA and cognitive performance (all p>0.1); however, estimated marginal means models indicated that the effect of MVPA on processing speed was evident only among rural BCS (Trails-B, p = 0.04; Mazes, p = 0.03). Conclusions Findings suggest rural BCS may suffer greater CACD and engage in less MVPA. Additional research is warranted to further examine CACD and more effectively promote MVPA in rural BCS

Contamination by an Active Control Condition in a Randomized Exercise Trial

<div><p>Contamination is commonly overlooked in randomized trials. The present study examined contamination (minutes of aerobic activity outside of exercise sessions) within an active control condition in a 6-month randomized exercise trial for older adults. We hypothesized that outside aerobic activity would be greater in the control condition compared to the intervention conditions. Participants (mean age = 65.06 years, 66.2% female) were randomly assigned to: Dance (n = 50), Walking, (n = 108), or Strength/Stretching/Stability (SSS; n = 48). Dance and Walking represented the experimental conditions and SSS the control condition. Participants attended exercise sessions three times weekly for 24 weeks. Participants recorded their physical activity outside of class on a weekly home log. Group assignment and covariates (age, gender, body mass index, exercise session intensity and enjoyment, and program adherence) were examined as predictors of weekly aerobic activity outside of exercise sessions. Participants who returned zero home logs were removed from the dataset (final N = 195). Out-of-class aerobic activity was lowest in the Walking group. Significant effects of gender, group, enjoyment, and intensity on out-of-class weekly aerobic activity were observed, all <i>p</i><0.003. Higher perceived enjoyment of exercise sessions was associated with more out-of-class aerobic activity, while higher perceived intensity was associated with less out-of-class aerobic activity. A group x intensity interaction, <i>p</i> = 0.002, indicated that group differences in out-of-class aerobic activity were evident only among those with lower intensity perceptions. Walkers may have perceived exercise sessions as sufficient weekly exercise, while the Dance and SSS groups may have perceived the sessions as necessary, but insufficient. The lower aerobic intensity Dancers attributed to exercise sessions and non-aerobic nature of SSS may partially explain contamination observed in this study. Further examination of contamination in randomized controlled exercise trials is critically needed.</p><p>Trial Registration</p><p>ClinicalTrials.gov <a href="https://clinicaltrials.gov/ct2/show/NCT01472744?term=NCT01472744&rank=1" target="_blank">NCT01472744</a></p></div

Replacing sedentary time with physical activity or sleep: effects on cancer-related cognitive impairment in breast cancer survivors

Abstract Background Evidence suggests reallocating daily sedentary time to physical activity or sleep confers important health benefits in cancer survivors. Despite emerging research suggesting physical activity as a treatment for cancer-related cognitive impairment (CRCI), little is known about the interactive effects of behaviors across the 24-h period. The present purpose was to examine the cognitive effects of reallocating sedentary time to light-intensity physical activity, moderate-to-vigorous physical activity (MVPA), or sleep in breast cancer survivors. Methods Breast cancer survivors (N = 271, Mage = 57.81 ± 9.50 years) completed iPad-based questionnaires and cognitive tasks assessing demographics, health history, executive function, and processing speed (Task-Switch, Trail Making). Participants wore an accelerometer for seven consecutive days to measure their sedentary, physical activity, and sleep behaviors. Single effects (each behavior individually) and partition (controlling for other behaviors) models were used to examine associations among behaviors and cognitive performance. Isotemporal substitution models were used to test the cognitive effects of substituting 30 min of sedentary time with 30 min of light-intensity activity, MVPA, and sleep. Results MVPA was associated with faster Task-switch reaction time in the partition models (stay: B = − 35.31, p = 0.02; switch: B = − 48.24, p = 0.004). Replacing 30 min of sedentary time with 30 min of MVPA yielded faster reaction times on Task-Switch stay (B = − 29.37, p = 0.04) and switch (B = − 39.49, p = 0.02) trials. In Trails A single effects models, sedentary behavior was associated with faster completion (B = − 0.97, p = 0.03) and light-intensity activity with slower completion (B = 1.25, p = 0.006). No single effects were observed relative to Trails B completion (all p > 0.05). Only the effect of MVPA was significant in the partition models (Trails A: B = − 3.55, p = 0.03; Trails B: B = − 4.46, p = 0.049). Replacing sedentary time with light-intensity activity was associated with slower Trails A (B = 1.55 p = 0.002) and Trails B (B = 1.69, p = 0.02) completion. Replacing light activity with MVPA yielded faster Trails A (B = − 4.35, p = 0.02) and Trails B (B = − 5.23, p = 0.03) completion. Conclusions Findings support previous research suggesting MVPA may be needed to improve cognitive function in breast cancer survivors. Trails findings underscore the need to dissect sedentary contexts to better understand the impact of daily behavioral patterns on CRCI. Additional research investigating the cognitive impacts of behaviors across the 24-h period is warranted. Trial registration This study is registered with United States ClinicalTrials.gov (NCT02523677; 8/14/2015)

Group differences in out-of-class aerobic activity overall and by perceived intensity of exercise sessions.

<p>*Mean unstandardized predicted values (adjusted for gender).</p

Weekly Aerobic Activity Outside of Program Sessions.

<p>Weekly Aerobic Activity Outside of Program Sessions.</p