Guy Faulkner

Sedentary Time and Its Association With Risk for Disease Incidence, Mortality, and Hospitalization in Adults: A Systematic Review and Meta-analysis

Adults are advised to accumulate at least 150 minutes of weekly physical activity in bouts of 10 minutes or more (1). The intensity of such habitual physical activity has been found to be a key characteristic of primary and secondary health prevention, with an established preventive role in cardiovascular disease, type 2 diabetes, obesity, and some cancer types (2, 3). Despite the health-enhancing benefits of physical activity, this alone may not be enough to reduce the risk for disease and illness. Population-based studies have found that more than one half of an average persons waking day involves sedentary activities ubiquitously associated with prolonged sitting, such as watching television and using the computer (4). This lifestyle trend is particularly worrisome because studies suggest that long periods of sitting have deleterious health effects independent of adults meeting physical activity guidelines (57). Moreover, physical activity and sedentary behaviors may be mutually exclusive. For example, some persons who achieve their recommended physical activity targets may be highly sedentary throughout the remainder of their waking hours, whereas others who may not regularly participate in physical activity may be nonsedentary because of their leisure activities, workplace environments, or both (8). Although studies and subgroups of systematic reviews have explored the independent association between sedentary behaviors and outcomes after adjustment for physical activity, the magnitude and consistency of such associations and the manner by which they change according to the level of participation in physical activity remain unclear (911). The objective of this meta-analysis was to quantitatively evaluate the association between sedentary time and health outcomes independent of physical activity participation among adult populations. We hypothesized that sedentary time would be independently associated with both cardiovascular and noncardiovascular outcomes after adjusting for participation in physical activity but that the relative hazards associated with sedentary times would be attenuated in those who participate in higher levels of physical activity compared with lower levels (10). Methods Data Sources and Searches The Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines were followed in the conduct and reporting of this meta-analysis (9). Published studies on the association between sedentary behavior and various health outcomes were identified and cross-checked by 2 reviewers through a systematic search of the MEDLINE, PubMed, EMBASE, CINAHL, Cochrane Library, Web of Knowledge, and Google Scholar databases. The health outcomes included all-cause mortality, cardiovascular disease incidence (including diabetes), cardiovascular disease mortality, cancer incidence, cancer mortality, and all-cause hospitalizations. Searches were restricted to English-language primary research articles through August 2014 with no publication date limitations (Supplement). The following keywords were applied to the search: (exercise OR physical activity OR habitual physical activity) AND (sedentar* OR inactivity OR television OR sitting) AND (survival OR morbidity OR mortality OR disease OR hospital* OR utilization). References from relevant publications and review articles were hand-searched to supplement the electronic searches. A broad and comprehensive search strategy was chosen to encompass the range of outcomes associated with sedentary behavior among different populations or settings and variations in the operational definition of leisure-time sedentary behavior. Supplement. Search Strategy Supplement. Original Version (PDF) Study Selection The inclusion criteria were primary research studies that assessed sedentary behavior in adult participants as a distinct predictor variable, independent of physical activity and correlated to at least 1 health outcome. We broadly defined sedentary behavior as a distinct class of waking behaviors characterized by little physical movement and low-energy expenditure (1.5 metabolic equivalents), including sitting, television watching, and reclined posture (11). We allowed for studies that assessed the effects of varying intensities of physical activity, provided that they also correlated a measure of sedentary behavior with an outcome. We excluded studies that assessed nonadult populations (such as children and youth), those that did not adjust for physical activity in their statistical regression models or only assessed sedentary behavior as a reference category to the effects of physical activity, and those that measured sedentary behavior as the lowest category of daily or weekly physical activity. Data Extraction and Quality Assessment Data were extracted from all articles that met selection criteria and deemed appropriate for detailed review by 3 authors. If several articles of the same study were found, then data were extracted from the most recently published article. Details of individual studies were collected and characterized on the basis of authors or year of publication; study design; sample size or characteristics (age and sex); data collection methods; study outcomes; study limitations; and hazard ratios (HRs), odds ratios, or relative risk ratios (and their associated 95% CIs or SEs). We restricted studies reporting health outcomes to those with direct associations with death, disease incidence (that is, risk for disease in a given period), and health service use (that is, change in health service use) outcomes. This led to the exclusion of studies reporting indirect surrogate outcomes with inconsistent clinical end points and cutoffs (such as insulin sensitivity, quality of life, activities of daily living, metabolic biomarkers, the metabolic syndrome, and weight gain). Our studys primary exposure was overall sedentary or sitting time (hours per week or hours per day). Studies reporting information on total screen time (television or computer screen use), television viewing time, and metabolic equivalents (hours per week) were also abstracted when information on the primary exposure was unavailable. We assessed articles for quality on the basis of methods used by Proper and colleagues (12). Their quality assessment tool had been previously validated (face and content) and evaluated to limit the risk of bias from study participation, study attrition, measurement of prognostic factors, measurement of and controlling for confounding variables, measurement of outcomes, and analysis approaches (13, 14). Each study was evaluated according to a standardized set of predefined criteria consisting of 15 items (Table 1) (15). The use of the original quality assessment tool was expanded to permit and score nonprospective studies. The items of the tool assessed study quality within the domains of study population, study attrition, data collection, and data analysis. Each quality criterion was rated as positive, negative, or unknown. As with other meta-analyses, we required positive quality criteria of 8 items or more to be included in our study (12, 16). Two reviewers independently scored each article for quality. Any scoring inconsistencies were discussed with an additional reviewer. Scores from each reviewer were averaged to attain a final quality score assessment and verified by a single reviewer. When such data were available, we also considered whether the effects of prolonged bouts of sedentary time were modified by the highest or lowest reported participation in physical activity (herein termed as joint effects). Table 1. Criteria List for the Assessment of the Quality of Prospective and Nonprospective Studies* Data Synthesis and Analysis All meta-analyses were done using Comprehensive Meta-analysis, version 2 (Biostat), and the metafor package of R (R Foundation for Statistical Computing) (17, 18). Odds ratios, relative risk ratios, and HRs with associated 95% CIs were collected from studies for each outcome, if available. We considered relative risk ratios to be equal to HRs, and when only odds ratios were provided, they were approximated to relative risk ratios in which we used the assumption of rare events according to methods described and demonstrated elsewhere (19, 20). When studies presented several statistical risk-adjustment models, we only considered relative risk ratios associated with the statistical models that contained the fewest number of additional covariates beyond physical activity to enhance comparability across studies. Adjustment for physical activity (rather than moderate to vigorous physical activity) allowed for a broader range of studies, some of which may not have specified the intensity of physical activity in regression models. KnappHartung small sample estimation was used to pool the analysis of the overall effect size for each outcome. Studies that separately presented results for men and women were combined using a fixed-effects model. We received a 79% response rate from authors we had contacted to provide additional statistical information for our meta-analysis (11 out of 14). Potential modifying effects of physical activity on sedentary time were examined by comparing the statistical effect sizes of any studies that reported the longest period of sedentary time with the highest and lowest duration and intensity of physical activity. Statistical heterogeneity was assessed using the Cochran Q statistic and the I 2 statistic of the proportion of total variation because of heterogeneity (21). When we saw substantial heterogeneity, we considered a KnappHartung modified random-effects model (22). For the summary estimate, a P value less than 0.05 was considered statistically significant. The potential for small study effects, such as publication bias, was explored graphically using funnel plots through the Egger test of asymmetry and quantitatively by the Egger linear regression method (23). We also did a sensitivit

Physical activity and older adults: a review of health benefits and the effectiveness of interventions

The purpose of this multidisciplinary review paper is to critically review evidence from descriptive, efficacy and effectiveness studies concerned with physical activity and older people. Both levels of fitness (aerobic power, strength, flexibility and functional capability) and measures of physical activity involvement decline with age, and the extent to which this is due to a biological ageing processes or disuse (physical inactivity) is critically examined. The review will consider the evidence for a causal relationship between sedentary behaviour/physical activity programmes and cardiovascular, musculoskeletal and psycho-social health, independent living and health-related quality of life into old age. The review also considers the effectiveness of different physical activity interventions for older people and issues relating to cost-effectiveness. The implications for future policy in terms of research, health care services, and education and training are briefly discussed.

Active school transport, physical activity levels and body weight of children and youth: A systematic review

OBJECTIVES Active school transport (AST) may be an important source of childrens physical activity (PA). Innovative solutions that increase PA time for children, without putting added pressure on the school curriculum, merit consideration. Before implementing such solutions, it is important to demonstrate that active school transport is associated with health-related outcomes. METHODS Following a standardized protocol, we conducted a systematic review of published research to address this question and explore whether children who actively commute to school also have a healthier body weight. Online searches of 5 electronic databases were conducted. Potential studies were screened on the basis of objective measures of physical activity. RESULTS Thirteen studies were included in this review. Nine studies demonstrated that children who actively commute to school accumulate significantly more PA and two studies reported that they expended significantly more kilocalories per day. Where studies examined body weight (n=10), only one reported active commuters having a lower body weight. CONCLUSIONS These studies demonstrate that active school commuters tend to be more physically active overall than passive commuters. However, evidence for the impact of AST in promoting healthy body weights for children and youth is not compelling.

Physical Activity and the Prevention of Depression: A Systematic Review of Prospective Studies

CONTEXT Given its high prevalence and impact on quality of life, more research is needed in identifying factors that may prevent depression. This review examined whether physical activity (PA) is protective against the onset of depression. EVIDENCE ACQUISITION A comprehensive search was conducted up until December 2012 in the following databases: MEDLINE, Embase, PubMed, PsycINFO, SPORTDiscus, and Cochrane Database of Systematic Reviews. Data were analyzed between July 2012 and February 2013. Articles were chosen for the review if the study used a prospective-based, longitudinal design and examined relationships between PA and depression over at least two time intervals. A formal quality assessment for each study also was conducted independently by the two reviewers. EVIDENCE SYNTHESIS The initial search yielded a total of 6363 citations. After a thorough selection process, 30 studies were included for analyses. Among these, 25 studies demonstrated that baseline PA was negatively associated with a risk of subsequent depression. The majority of these studies were of high methodologic quality, providing consistent evidence that PA may prevent future depression. There is promising evidence that any level of PA, including low levels (e.g., walking <150 minutes/weeks), can prevent future depression. CONCLUSIONS From a population health perspective, promoting PA may serve as a valuable mental health promotion strategy in reducing the risk of developing depression.

Active school transportation in the Greater Toronto Area, Canada: an exploration of trends in space and time (1986-2006).

OBJECTIVE This study describes temporal and spatial trends in active transportation for school trips in the Greater Toronto Area, Canadas largest city-region. METHODS Proportions of trips by travel mode to and from school were estimated and compared for children (11-13 years) and youth (14-15 years). Data were drawn from the 1986, 1996, 2001, and 2006 versions of the Transportation Tomorrow Survey (TTS). RESULTS Between 1986 and 2006, walking mode share for trips to school declined (53.0%-42.5% for 11-13 year olds, 38.6%-30.7% for 14-15 year olds). Although there has also been a decline in walking home from school, walking rates were higher in the afternoon. In 2006, younger children in the suburbs walked less to school (36.1%-42.3% of trips) than 11-13 year olds in Toronto (48.1%) and Torontos 14-15 year olds walked less (38.3% of trips) but used transit more (44.8% of trips) than students in the suburbs. CONCLUSION The findings indicate a period of decline (1986-2006) in the use of active modes for journeys to and from school for both age groups. Policies and programs to increase active transportation should acknowledge the spatial, temporal, and demographic heterogeneity of school travel decisions and outcomes.

Validation of a physical activity assessment tool for individuals with schizophrenia

OBJECTIVE Increasing physical activity must be one component of lifestyle interventions designed to prevent or treat obesity in schizophrenia and there is now a need to develop low cost, practical and accurate measures of physical activity in this population to identify the prevalence of physical (in)activity and to assess the effectiveness of physical activity interventions. The objective of this study was to provide preliminary validation of the Short-Form International Physical Activity Questionnaire (IPAQ), a measurement tool that could prove useful for both clinicians and researchers in the field. METHOD Reliability and validity data were collected from a sample of 35 outpatients with a DSM-IV diagnosis of schizophrenia. Test-retest repeatability was assessed within the same week and criterion validity was assessed against an RT3 accelerometer. Spearmans correlation coefficients are reported based on the total reported physical activity (minutes) and estimated energy expenditure. RESULT We found a correlation coefficient of 0.68 for reliability and 0.37 for criterion validity based on total reported minutes of physical activity. There was a nonsignificant correlation (0.30; p>0.05) between the RT3 data and estimated energy expenditure derived from the IPAQ. CONCLUSION Although not without limitations, the Short-Form IPAQ, when used with individuals with schizophrenia, exhibits measurement properties that are comparable to those reported in the general population and can be considered as a surveillance tool to assess levels of physical activity.

Schizophrenia and weight management: a systematic review of interventions to control weight

Objective: Weight gain is a frequent side effect of antipsychotic medication which has serious implications for a patients health and well being. This study systematically reviews the literature on the effectiveness of interventions designed to control weight gain in schizophrenia.

GIS measured environmental correlates of active school transport: A systematic review of 14 studies

BackgroundEmerging frameworks to examine active school transportation (AST) commonly emphasize the built environment (BE) as having an influence on travel mode decisions. Objective measures of BE attributes have been recommended for advancing knowledge about the influence of the BE on school travel mode choice. An updated systematic review on the relationships between GIS-measured BE attributes and AST is required to inform future research in this area. The objectives of this review are: i) to examine and summarize the relationships between objectively measured BE features and AST in children and adolescents and ii) to critically discuss GIS methodologies used in this context.MethodsSix electronic databases, and websites were systematically searched, and reference lists were searched and screened to identify studies examining AST in students aged five to 18 and reporting GIS as an environmental measurement tool. Fourteen cross-sectional studies were identified. The analyses were classified in terms of density, diversity, and design and further differentiated by the measures used or environmental condition examined.ResultsOnly distance was consistently found to be negatively associated with AST. Consistent findings of positive or negative associations were not found for land use mix, residential density, and intersection density. Potential modifiers of any relationship between these attributes and AST included age, school travel mode, route direction (e.g., to/from school), and trip-end (home or school). Methodological limitations included inconsistencies in geocoding, selection of study sites, buffer methods and the shape of zones (Modifiable Areal Unit Problem [MAUP]), the quality of road and pedestrian infrastructure data, and school route estimation.ConclusionsThe inconsistent use of spatial concepts limits the ability to draw conclusions about the relationship between objectively measured environmental attributes and AST. Future research should explore standardizing buffer size, assess the quality of street network datasets and, if necessary, customize existing datasets, and explore further attributes linked to safety.

Exercise as an adjunct treatment for schizophrenia: A review of the literature

Previous reviews of the exercise and mental health literature have predominantly examined non-clinical populations and clinical populations with anxiety and/or depressive disorders. There is growing, albeit limited, evidence that exercise can also be an effective adjunctive treatment for other clinical disorders such as alcohol abuse, somatoform disorders and psychosis. This review examines the literature that has investigated the use of exercise as an adjunct treatment for schizophrenia. While methodological concerns are evident in the literature, attention is drawn to the difficulties of assessing traditional exercise interventions with such a population and the need for greater acceptance of methodological diversity. The existing research indicates that exercise is a useful adjunct for some of the negative symptoms of schizophrenia in addition to depression and anxiety. Additionally, the use of exercise as a coping strategy for positive symptoms, such as auditory hallucinations, has been suggested. Mec...

Canadian 24-Hour Movement Guidelines for Children and Youth: An Integration of Physical Activity, Sedentary Behaviour, and Sleep1

Leaders from the Canadian Society for Exercise Physiology convened representatives of national organizations, content experts, methodologists, stakeholders, and end-users who followed rigorous and transparent guideline development procedures to create the Canadian 24-Hour Movement Guidelines for Children and Youth: An Integration of Physical Activity, Sedentary Behaviour, and Sleep. These novel guidelines for children and youth aged 5-17 years respect the natural and intuitive integration of movement behaviours across the whole day (24-h period). The development process was guided by the Appraisal of Guidelines for Research Evaluation (AGREE) II instrument and systematic reviews of evidence informing the guidelines were assessed using the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach. Four systematic reviews (physical activity, sedentary behaviour, sleep, integrated behaviours) examining the relationships between and among movement behaviours and several health indicators were completed and interpreted by expert consensus. Complementary compositional analyses were performed using Canadian Health Measures Survey data to examine the relationships between movement behaviours and health indicators. A stakeholder survey was employed (n = 590) and 28 focus groups/stakeholder interviews (n = 104) were completed to gather feedback on draft guidelines. Following an introductory preamble, the guidelines provide evidence-informed recommendations for a healthy day (24 h), comprising a combination of sleep, sedentary behaviours, light-, moderate-, and vigorous-intensity physical activity. Proactive dissemination, promotion, implementation, and evaluation plans have been prepared in an effort to optimize uptake and activation of the new guidelines. Future research should consider the integrated relationships among movement behaviours, and similar integrated guidelines for other age groups should be developed.