Author Archive: Joel
This is one of the questions that will be addressed at the upcoming, Loch Lomond Lectures – Context is Key: Unlocking Physical Behaviour Data.
This event is a small, informal and participative retreat style meeting hosted by Malcolm Granat, Professor of Health and Rehabilitation Sciences, School of Health Science, University of Salford, and featuring several renowned international speakers.
When: 7 & 8 June 2015
Location: Loch Lomond, Scotland
March 23-29 is Unplug and Play Week in Canada. From ParticipACTION:
Turn off the screens. Turn up the play.
Now that our electronics are only ever a finger’s reach away, the average Canadian child spends close to 8hrs a day in front of a screen. So let’s help our children by leading by example. Let’s put our electronics down for at least 60 minutes a day and get outside for some physical activity. To help, here’s an Unplug & Play Checklist with a week’s worth of ideas. You’ll also find a customizable certificate to award your little ones if they stay active for all 7 days.
The site also offers a screen time log to track screen time. Happy Unplug and Play Week!
There will be an event titled ‘Physical activity & sedentary behaviour surveillance & assessment – maximizing Europe’s resources” at the EXPO in Milan on 14 May.
Please see the program attached or check the registration website:
A pdf providing an overview of the workshop can be found below.
Author Summary of “Sedentary Time and Its Association with Risk for Disease Incidence, Mortality, and Hospitalization in Adults” paper, Published in the Annals of Internal Medicine (2015: 162:123-132)
Today’s post is a summary of a fascinating new paper published in Annals of Internal Medicine on the relationship between sedentary behaviour and premature mortality (available here). The summary is written by lead author Avi Biswas; you can find more on Avi at the bottom of this post. This post is also available at PLoS Blogs.
In a similar vein to other reviews that have examined the association between sedentary time and various health outcomes, our study sought to not only update the sedentary behavior literature but also focus exclusively on studies that adjusted for physical activity in order to assess the independent effects of sedentary time. This differentiated our meta-analysis from two others which had previously reported independent risks (Wilmot et al., 2012 and Schmid and Leitzmann, 2014), as investigating the independent effects of sedentary time (by reporting the effects from studies that at least adjusted for physical activity) was our core focus rather than among a limited subgroup of available studies. Additionally, our study examined the extent to which levels of physical activity may potentially modify the associations between sedentary time and outcomes, which to the best of our knowledge has not been systematically quantified in other reviews.
What we did
We devised a comprehensive, systematic search strategy of studies that assessed sedentary behavior in adults as a predictor variable and correlated to at least one health outcome. We also focused on direct clinical outcomes (death, disease incidence and health service use) rather than indirect surrogate outcomes such as quality of life, insulin sensitivity and weight gain) as we believed the later type would present inconsistent end points and cutoffs. We then collected the statistical effects associated with the longest reported sedentary time (vs. a baseline of the lowest sedentary time) and that adjusted for physical activity. These were used to pool the analysis of the overall effect for each outcome.
When examining whether physical activity modifies the effects associated with sedentary time, we reanalyzed all available studies that met our selection criteria to see if they reported statistical effects of the longest period of sedentary time with the highest duration and intensity of physical activity.
What we found
Our study found that long periods of sedentary time was positively associated with an increased risk for dying (from all-causes, cancer and cardiovascular diseases) and increasing the risk for certain forms of cancer (specifically breast, colon, colorectal, endometrial, and epithelial ovarian cancer), cardiovascular disease and type 2 diabetes. Our meta-analysis found that the largest association was with type 2 diabetes (91% increased risk).
Of the limited studies that reported the joint effects of physical activity and sedentary time (only quantified for dying from all-causes), our pooled analysis found that the risk of dying from all-causes due to long sedentary time was 30% greater in those who spent little to no time in regular physical activity than those who at least met their physical activity recommendations of 30 minutes/day. While the pooled effect corresponding to high levels of physical activity and long sedentary time were found not to be statistically significant, we believe the consistent and strong effects associated across all-cause mortality-assessed studies (and to a lesser degree, cardiovascular disease and mortality) suggests that there is a strong likelihood that physical activity alone does not completely reduce the negative effects from long sitting time. We believe more work needs to be done to tease out whether there is such an association.
Take home message
Our study provides the strongest evidence as so far, to suggest that long periods of sitting is associated with various health outcomes. Furthermore, while regular or high levels of physical activity seems to have protective effects on reducing sedentary time-associated risks, we believe there is sufficient evidence to suggest that a focus on promoting regular exercise AND reducing sitting time to be a better public health message.
About the Authors
Avi is a PhD candidate at the Institute of Health Policy, Management and Evaluation, University of Toronto and the Toronto Rehabilitation Institute. Along with this meta-analysis study, his PhD work is focused on understanding the risks of sedentary behaviour among exercise-engaged cardiac rehabilitation patients, in lieu of developing non-sedentary interventions.
Dr. Alter is a Senior Scientist at the Institute of Clinical Evaluative Sciences and research director of the Toronto Rehabilitation Institute’s Cardiovascular Prevention and Rehabilitation program. Dr. Alter’s research spans across many disciplines including cardiovascular health services and outcomes, clinical epidemiology and social determinants, cardiac rehabilitation and more recently, music and medicine. He has published over 125 scholarly peer reviewed papers in prestigious journals such as the New England Journal of Medicine and the Journal of the American Medical Association. Dr. Alter has also received funding from various agencies including the Heart and Stroke Foundation of Ontario.
Today’s post comes from PhD Candidate Justin Lang. For media requests or further information on the study, please contact Justin directly at jlang
In recent years there has been an accumulation of evidence indicating that sedentary behaviors (i.e., sitting) are associated with negative health outcomes, such as cardiovascular disease, diabetes, and premature mortality. In light of this evidence, researchers are trying to develop creative interventions to reduce sedentary behaviors – one of which being point-of-decision prompts (PODP). PODPs are used to inform individuals about the health benefits associated with a specific behavior. For instance, PODP are used in the workplace to remind people to stand throughout the day; they are also used to encourage individuals to use the stairs rather than the elevator.
We were interested in testing PODPs as an intervention to encourage standing during the Global Summit on the Physical Activity of Children and Youth conference (Toronto, Ontario, May 2015). Conferences are an excellent venue for sedentary behavior research as they typically involve periods of uninterrupted sitting, especially during oral presentation. Thus, the purpose of our study was to determine if a PODP would influence the proportion of attendees standing during oral presentations.
What did we do?
We selected 12 of 16 oral presentation sessions that took place during the conference. Each presentation session included 4 different, 15 minute, oral presentations on various topics related to physical activity. We then randomly assigned 6 presentation sessions to the intervention group and the remaining 6 presentation sessions to the control group.
During the intervention group sessions we asked the facilitators to read the prompt (see below) at the beginning (before the first presenter) and middle (after the second presenter) of the session.
Prolonged sitting is associated with increased health risks. We encourage you to reduce and/or interrupt your sedentary time while attending the Global Summit on the Physical Activity of Children. Please feel free to stand during this presentation session.
Facilitators for the control group sessions were asked not to address sitting and/or standing, and to not mention the existence of the study.
During all 12 sessions, researchers counted the number of participants at the beginning (first 10 min), middle (30-40 min), and end (50-60 min) of the session. Each count consisted of (a) the number of individuals in the room and (b) the number of standing individuals at any time during the count period.
What did we find?
The results of this study indicated that individuals were significantly more likely to stand during presentation sessions that included the PODP (see Figure 1). Roughly 60% more participants stood during the sessions with the PODP, when compared to the control group.
Our study suggests that frequent prompts and/or permission to stand results in a great proportion of people choosing to do so. This is an exciting finding because it supports the versatility of PODPs. Prompts represent an equitable population health intervention. In other words, they have the potential to influence a large group of individuals equally. In addition, PODPs have little to no cost associated with their implementation.
About the author:
Justin Lang is a PhD candidate in the Population Health program at the University of Ottawa and holds a research assistantship with the Healthy Active Living and Obesity Research Group at CHEO. His PhD research focus is on the geographic variation of physical fitness in children and it’s relationship with childhood obesity. Justin also holds a Mitacs internship which provides him with the opportunity to further explore physical fitness in the Ottawa community.
Lang, J. J., McNeil, J., Tremblay, M. S., & Saunders, T. J. (2015). Sit less, stand more: A randomized point-of-decision prompt intervention to reduce sedentary time. Preventive Medicine. Available here.
A systematic review and meta-analysis on the link between sedentary time and health outcomes in adults that was published today is receiving significant attention in the media. The title of the paper is, “Sedentary Time and Its Association With Risk for Disease Incidence, Mortality, and Hospitalization in Adults: A Systematic Review and Meta-analysis,” and was published in the Annals of Internal Medicine today. Note: several SBRN members are among the authors on the paper.
According to Dr. David Alter, lead researcher of the study and a senior scientist at the Toronto Rehabilitation Institute, “More than one half of an average person’s day is spent being sedentary — sitting, watching television or working at a computer. Our study finds that despite the health-enhancing benefits of physical activity, this alone may not be enough to reduce the risk for disease.”
Click on the links below to follow media coverage on this study:
- Excessive sitting linked to disease, premature death – Globe & Mail
- Sitting for too long can kill you, even if you exercise: study – CBC
- Too much sitting raises risk of death, even if you exercise – Full Time Whistle
- Sitting All Day Sitting Linked To Disease, Premature Death Even With Regular Exercise – Huffington Post
- Sitting on your butt too much may be deadly: study – Metro
- Too Much Sitting Linked to Increased All-Cause Mortality – Medscape
- Sitting too long increases risk of dying early – SMN Weekly
- Even with exercise, excessive sitting may be deadly – Missions Record
- Even with regular exercise, excessive sitting linked to disease, premature death – News 1130
- Even for the active, a long sit shortens life and erodes health – LA Times
- Exercising regularly WON’T offset the risk of sitting for long periods of time: An hour of activity a day isn’t enough to stave off heart disease, diabetes and cancer, study finds – Daily Mail UK
- It Doesn’t Matter How Much You Exercise If You Also Do This – Time
Biswas A, Oh PI, Faulkner GE, Bajaj RR, Silver MA, Mitchell MS, Alter DA. Sedentary Time and Its Association With Risk for Disease Incidence, Mortality, and Hospitalization in Adults: A Systematic Review and Meta-analysis. Ann Intern Med. 2015 Jan 20;162(2):123-132. doi: 10.7326/M14-1651.
Today’s post comes from Mai Chinapaw and Teatske Altenburg. Their lab website can be found here.
A recent commentary by Chinapaw et al. (Prev Med 2014) critically discussed the current evidence on the association between sedentary behaviour and cardiometabolic health in children. The authors conclude that in children, there is no convincing evidence yet on the association between sedentary behaviour and cardiometabolic health. One of the highlighted challenges to advance this field is improving the measurement of sedentary behaviour including total sedentary time and sedentary time accumulated in bouts. Two recent papers examined this important issue.
The first paper (Chinapaw et al., PLoS ONE 2014) aimed to establish evidence-based accelerometer data reduction criteria for assessment of sedentary behaviour patterns in children. This is the first study that examined the influence of data reduction procedures on the number or duration of sedentary bouts in children. The authors formulated the following recommendations: 1) a minimum of 60 minutes of consecutive zeros as the most realistic criterion for non-wear time; and 2) including at least six days with minimum eight valid hours to characterize children’s usual total sedentary time and sedentary time accumulated in bouts, preferably including one weekend day.
The second paper (Altenburg et al., Prev Med 2015) examined occurrence and durations of bouts based on various definitions (bouts of at least 5, 10, 20 or 30 min, allowing 0, 30 or 60 sec >100cpm) in 10-12 year old children. Estimates of sedentary time accumulated in bouts varied largely between the different bout definitions. Generally, children sat mostly in sedentary bouts of at least 5 min, while 20 min bouts were rare. For none of the operational definitions the authors found convincing evidence for a cross-sectional association with cardiometabolic health indicators in 10-12 year old children. However, more significant associations appeared when allowing no tolerance (i.e. zero sec >100cpm). Therefore, the authors recommend that no tolerance should be allowed within a sedentary bout.
Both papers emphasise the need for standardized definitions of sedentary bouts as well as a consensus regarding accelerometer data-reduction criteria to advance the field of sedentary behaviour and the potential associated health risk. Moreover, sedentary behaviour researchers cannot rely on accelerometer data reduction procedures established for assessing physical activity.
- Chinapaw MJM, Altenburg TM, Brug, J (2014). Sedentary behaviour and health in children – Evaluating the evidence. Prev Med 70: 1-2.
- Chinapaw MJM, de Niet M, Verloigne M, De Bourdeaudhuij I, Brug J, Altenburg TM (2014). From sedentary time to sedentary patterns: accelerometer data reduction decisions in youth. PLoS ONE 9(11): e111205. doi:10.1371/journal.pone.0111205.
- Altenburg TM, de Niet M, Verloigne M, De Bourdeaudhuij I, Androutsos O, Manios Y, Kovacs E, Bringolf-Isler B, Brug J, Chinapaw MJM (2015). Occurrence and duration of various operational definitions of sedentary bouts and cross-sectional associations with cardiometabolic health indicators: the ENERGY-project. Prev Med 71: 101-106.
On the 8th and 9th of June 2015, a workshop is organised on determinants of sedentary behaviour across the life course, as a satellite of the ISBNPA annual meeting. This workshop is organised by Dr. Sebastien Chastin and Prof. Greet Cardon, on behalf of the DEDIPAC consortium. DEDIPAC (Determinants of Diet and Physical Activity) aims to establish a European trans-disciplinary research network with a joint research agenda and it also tries to build capacity to advance understanding of the complex interplay of the numerous determinants of sedentary behaviours.
Reducing sedentary behaviour is a public health challenge internationally. Currently, there is disparate and limited knowledge about the determinants of sedentary behaviour across the life course to inform interventions. This workshop will bring together epidemiologists, psychologists, clinicians, economists, rehabilitation, life, health, behavioural and social scientists to discuss the interaction between biological, psychological, sociological, economic, ecological, and socio-economic factors that determine sedentary behaviour. Experts will be invited and in-depth multidisciplinary discussions will be held on; how these mechanisms change over the life course, how these factors and their interactions differ between social and ethnic groups and what are the right targets for actions at multiple levels. The objective of the meeting is to finalise a transdisciplinary consensus framework for research on determinants of sedentary behaviour across the life course. The workshop will follow an interactive Delphi process, and international speakers like Jo Salmon, John Reilly, Genevieve Healy, Dawn Skelton, Neville Owen and David Conroy will talk about determinants of sedentary behaviour throughout this workshop.
You can subscribe to this satellite meeting by clicking here.
Today’s post comes from friend and colleague Dr Stephanie Prince, discussing her important new paper published in Obesity Reviews (available free here). More on Stephanie can be found at the bottom of this post.
Physical activity has long been established as a strong predictor of cardiometabolic health, disease and mortality. For decades now researchers have been trying to develop interventions that will increase our physical activity levels, most notably at higher intensities – think moderate-to-vigorous physical activity (otherwise known as MVPA). In Canada, we have physical activity guidelines which promote that adults (18-64 years) aspire to achieve a minimum of 150 minutes of MVPA per week in bouts of 10 minutes or more, with the idea that more physical activity is always better. Canadians also have sedentary behaviour guidelines for children and youth which propose limits on screen time.
There is a rapidly growing body of literature which suggests that greater amounts of time spent being sedentary (watching TV, screen time, sitting time, total sedentary time) are associated with an increased risk for markers of cardiometabolic disease, cardiovascular disease, diabetes, some cancers and premature death (references here and here). Sedentary behaviours refer to the time spent sitting or lying down and in a state where there is relatively minimal energy expended (not just the absence of MVPA).
While there has been a lot of research looking at the effectiveness of physical activity interventions, little has been done to examine whether these interventions also decrease the time we spend being sedentary. Prior to this review I often wondered whether the opposite might occur whereby individuals who increased their physical activity levels may become more sedentary almost has a consequence of the satisfaction that they had already undertaken the necessary amount of physical activity needed to meet physical activity guidelines. Although in its infancy compared to the physical activity field, the sedentary behaviour field is now proposing and testing a variety of interventions targeting sedentary behaviours exclusively (with the majority to date having focused on office environments, where many of us spend the majority of ours days sitting at desks in front of computers). While the efficacy of physical activity interventions is more known, it remains unknown whether these intervention also have the capacity to decrease sedentary time. Further it is unknown whether interventions which target sedentary behaviours are any better at reducing these behaviours than physical activity interventions.
Therefore, the objective of our research was to systematically review the literature and compare the effectiveness of interventions with a focus on physical activity and/or sedentary behaviours (e.g.physical activity only interventions vs. physical activity + sedentary behaviour interventions vs. sedentary behaviour only interventions) for reducing time spent being sedentary in adults.
What did we do?
To examine all available literature we conducted a systematic review which searched six different bibliographic databases (you can see more details on this in the full article) looking for any study which described a physical activity and/or sedentary behaviour intervention and reported on changes in total sedentary time or time spent watching TV or sitting among adults. All of the studies included in the review can be found in the supplemental tables found here. We were also very fortunate to obtain several unpublished results provided to us upon request from authors of original studies where sedentary time was captured, but not reported upon in previous articles.
We assessed the quality and risk of bias of every individual study and also used the GRADE (Grading of Recommendations Assessment, Development and Evaluation) framework, essentially the gold standard for assessing the overall quality of the evidence and for rendering a recommendation based on the current evidence.
[Travis’ note: This was a lot of work!!!]
What did we find?
After we removed duplicate papers, we ended up retrieving 9,107 relevant papers. That was a lot of papers to screen! After many hours and days looking at the abstracts and then the full articles, 63 studies were kept in the review having met our inclusion criteria. Of these 63, 33 were used in the meta-analyses which allowed us to group quantitative results to yield an overall effect of the interventions. See Figure 1 for the PRISMA flow diagram to get a sense of how we screened out papers.
When we examined all of the evidence looking at both the more descriptive results of what the studies found and also at the quantitative results (see Figure 3 above) we found that on average the physical activity interventions resulted in significant, though very small reductions in sedentary time (average difference of 19 minutes/day). When interventions had both a physical activity and sedentary behaviour component they resulted in significant, but slightly greater reductions in sedentary time (average difference of 35 minutes/day) (Figure 4). Most promising is that when interventions focused solely on the behaviour itself, they yielded an average reduction of 91 minutes/day.
Today’s post comes from Juliet Harvey. You can find out more about Mrs Harvey at the bottom of this post. To submit your own post describing research of interest on sedentary behaviour, please contact email saunders dot travis at gmail dot com.
With recent studies suggesting a link between sedentary behaviour, health and well-being it is important to consider the sedentariness of older adults. Two recent systematic reviews have examined the levels of sedentary behaviour in older adults. Both papers took a global perspective and examined a range of measurement of sedentary behaviour reported by peer reviewed sources.
The first paper (Harvey et al., 2013) examined the prevalence of sedentary behaviour, where “cut-points” were used to give population prevalence of various levels and modes of sedentary behaviour. Almost 60% of older adult’s reported sitting for more than 4 h per day, 65% sat in front of a screen for more than 3 h daily and over 55% reported watching more than 2 h of TV. However, when measured objectively, in a small survey, it was found that 67% of the older population were sedentary for more than 8.5 h daily.
The second paper (Harvey et al., 2014) examined the average levels of sedentary behaviour reported by and measured in older adults. Objective measurement of SB, by accelerometry, shows that older adults spend an average of 9.4 hours daily sedentary in a waking day. Self-report of SB is lower at 5.3 hours daily, with 3.3 hours TV viewing reported.
As is seen in other studies, both papers found there were various methods employed to define and measures sedentary behaviour. There were vast difference between objective and subjective measurement of sedentary behaviour. These papers show that older adults do exhibit high levels of sedentary behaviour, which are similar to that of the adult population, despite the fact they may accumulate the sedentary time in different patterns.
About the author: Juliet Harvey is a physiotherapist and researcher in the Institute for Applied Health Research at Glasgow Caledonian University. Her research focuses on reducing sedentary behaviour in older adults. Juliet hopes to complete her PhD by summer 2015. Her contact details can be found here.