166 posts · 257,061 views
Obesity is a complex and multifactorial chronic disease that remains a military and public health priority in the United States. Recently, we’ve identified a strong association between obesity prevalence and altitude within the US. Our findings were surprising because they indicated the magnitude of this association was large and the pattern of association exhibited a curvilinear dose response in 500 meter categories of altitude. There was a 4-5 fold increase in obesity prevalence at low a........ Read more »
Voss, J., Masuoka, P., Webber, B., Scher, A., & Atkinson, R. (2013) Association of elevation, urbanization and ambient temperature with obesity prevalence in the United States. International Journal of Obesity. DOI: 10.1038/ijo.2013.5
Today’s post comes courtesy of my friend and frequent collaborator Dr Jean-Philippe Chaput. It is a Letter to the Editor that was written by Dr Chaput along with Angelo Tremblay and Eric Doucet in response to a recent paper in the Journal of the American Medical Association.... Read more »
One factor that may link sedentary behaviour with increased morbidity and mortality is the accumulation of visceral fat (see figure below), which has been linked with various chronic diseases and even death. For example, see this study by our former labmate Jen Kuk, which found that visceral fat was an independent predictor of premature death in men. While other types of body fat (e.g. butt fat) don’t tend to have a huge health impact, excess visceral fat is definitely a bad thing (more ........ Read more »
Saunders, T., Tremblay, M., Després, J., Bouchard, C., Tremblay, A., & Chaput, J. (2013) Sedentary Behaviour, Visceral Fat Accumulation and Cardiometabolic Risk in Adults: A 6-Year Longitudinal Study from the Quebec Family Study. PLoS ONE, 8(1). DOI: 10.1371/journal.pone.0054225
Mental work stimulates cardiovascular functions in healthy adults and a reduction in cardiac parasympathetic modulation could be one mechanism involved in such a response. The influence of sex on these cardiovascular responses remains ambiguous. The aim of the study was to evaluate cardiovascular impacts of mental work in healthy individuals and whether sex influences cardiovascular responses induced by mental work.... Read more »
Emilie Perusse-Lachance, Angelo Tremblay, Jean-Philippe Chaput, Paul Poirier, Normand Teasdale, Vicky Drapeau, Caroline Senecal, & Patrice Brassard. (2012) Mental Work Stimulates Cardiovascular Responses through a Reduction in Cardiac Parasympathetic Modulation in Men and Women. Bioenergetics: Open Access. info:/http://dx.doi.org/10.4172/2167-7662.S1-001
... Read more »
As many of our regular readers know (and often remind each other in the comments), body mass index is not a great predictor of an individual’s risk of disease. It predicts health risk at the population level, but even then there is considerable variation within a given BMI range. Peter has talked about this at length in the past, when he summarized 3 reasons why BMI is a poor measure of your health:... Read more »
Krakauer NY, & Krakauer JC. (2012) A new body shape index predicts mortality hazard independently of body mass index. PloS one, 7(7). PMID: 22815707
A very quick post today to point out an interesting new paper in the journal BMJ Open. Written by Peter Katzmarzyk (Peter J and I took his epi course while at Queen’s University) and I-Min Lee, the paper estimates the impact of both sedentary behaviour (e.g. all sitting) and television viewing on the life expectancy of Americans.... Read more »
Katzmarzyk, P, & Lee, I-Min. (2012) Sedentary behaviour and life expectancy in the USA: a cause-deleted life table analysis. BMJ Open. DOI: 10.1136/bmjopen-2012-000828
That’s right – the average Canadian kid spends almost 8 full hours in front of a screen based device everyday. I hadn’t heard the stat before so I went to the reference paper, which can be accessed for free here.
The data comes from the Canadian Youth Smoking Survey (YSS), which is a nationally representative survey of nearly 52 000 Canadians in grades 6-12 (when a survey is nationally representative, it means that the distribution of participants from various regions, ethn........ Read more »
Leatherdale ST, & Ahmed R. (2011) Screen-based sedentary behaviours among a nationally representative sample of youth: are Canadian kids couch potatoes?. Chronic diseases and injuries in Canada, 31(4), 141-6. PMID: 21978636
Exciting news – this week the Sedentary Behaviour Research Network published an updated definition of the terms “sedentary” and “sedentary behaviour” in French and English in the journals Applied Physiology, Nutrition and Metabolism and Movement & Sport Sciences – Science & Motricité.
In brief, the new definition states that to be engaging in “sedentary behaviour”, you must meet three very basic criteria:
You must be expending very lit........ Read more »
Sedentary Behaviour Research Network. (2012) Letter to the Editor: Standardized use of the terms "sedentary" and "sedentary behaviours". Applied physiology, nutrition, and metabolism . PMID: 22540258
Have you ever wondered how much salt is actually in those French fries from your favourite fast food outlet? New research published this week in the Canadian Medical Association Journal suggests that the answer to this question depends largely on your home address.... Read more »
Dunford, E., Webster, J., Woodward, M., Czernichow, S., Yuan, W., Jenner, K., Mhurchu, C., Jacobson, M., Campbell, N., & Neal, B. (2012) The variability of reported salt levels in fast foods across six countries: opportunities for salt reduction. Canadian Medical Association Journal. DOI: 10.1503/cmaj.111895
Last week a fascinating study was published by SBRN member David Dunstan and colleagues in Australia, which examined the acute (e.g. short-term) impact of uninterrupted sitting on metabolic health. In this new study, individuals with overweight or obesity were asked to perform 3 separate conditions in random order.
Uninterrupted sitting – participants sat for 5 consecutive hours
Sitting plus light intensity breaks – similar to the uninterrupted sitting condition, except ........ Read more »
Dunstan, D., Kingwell, B., Larsen, R., Healy, G., Cerin, E., Hamilton, M., Shaw, J., Bertovic, D., Zimmet, P., Salmon, J.... (2012) Breaking Up Prolonged Sitting Reduces Postprandial Glucose and Insulin Responses. Diabetes Care. DOI: 10.2337/dc11-1931
Nygaard, H., Tomten, S., & Høstmark, A. (2009) Slow postmeal walking reduces postprandial glycemia in middle-aged women. Applied Physiology, Nutrition, and Metabolism, 34(6), 1087-1092. DOI: 10.1139/H09-110
Until recently, only one set of physical activity guidelines was available for children under the age of 5 years (National Association for Sport and Physical Education, 2009). These guidelines were useful recommendations for parents and caregivers with advice on healthy living, but were informed largely on expert consensus and not by the rigor of a systematic review. Last year, Australia and the United Kingdom (UK) were the first to release evidence-based guidelines and recommend that preschool........ Read more »
Tremblay MS, LeBlanc AG, Carson V, Choquette L, Connor Gorber S, Dillman C, Duggan M, Gordon MJ, Hicks A, Janssen I.... (2012) Canadian Physical Activity Guidelines for the Early Years (aged 0–4 years). Applied Physiology, Nutrition and Metabolism. info:/
I recently came across a very interesting study published in Circulation in 2001. In it, authors Darren McGuire and colleagues perform the 30-year follow-up on a group of 5 men who had taken part in the Dallas Bed Rest and Training Study (DBRTS). The DBRTS took place in 1966, when all 5 men were healthy 20 year-olds. They were assessed extensively at baseline, following 3 months of bed rest, and following 8 weeks of physical training. In 1996 these same 5 men were re-assessed, allowing the re........ Read more »
McGuire DK, Levine BD, Williamson JW, Snell PG, Blomqvist CG, Saltin B, & Mitchell JH. (2001) A 30-year follow-up of the Dallas Bedrest and Training Study: I. Effect of age on the cardiovascular response to exercise. Circulation, 104(12), 1350-7. PMID: 11560849
Today we will look at other potential contributors to the pediatric obesity epidemic which I didn’t include in my paper. There are a few reasons for that – some risk factors are ones that I just felt didn’t have much evidence behind them, others were similar to ones that were included, and some just didn’t fit within the space constraints (since this paper was originally written for my comprehensive exams, it was limited to 15 pages).... Read more »
In Part 1 we examined the impact of changes in physical activity and sedentary behaviour, in Part 2 we looked at changes in food intake, and in Part 3 we looked at sleep, breastfeeding, maternal age and pollution. Today we look at the evidence (or lack thereof) linking adult obesity with the pediatric obesity epidemic, then examine the relative contributions of all of the risk factors we’ve discussed so far.... Read more »
In Part 1 we examined the impact of changes in physical activity and sedentary behaviour, and in Part 2 we looked at changes in food intake. Today we look at the evidence (or lack thereof) linking sleep, pollution, maternal age and breastfeeding with the pediatric obesity epidemic.... Read more »
Just because one study finds a relationship between A and B, does not mean that other studies will be able to replicate that finding, or that it will extend to other situations. On the face of it, this seems like an incredibly obvious statement. And yet it’s something that newspapers often forget, and which I think could have some very negative consequences.... Read more »
Goldfield, G., Kenny, G., Hadjiyannakis, S., Phillips, P., Alberga, A., Saunders, T., Tremblay, M., Malcolm, J., Prud'homme, D., Gougeon, R.... (2011) Video Game Playing Is Independently Associated with Blood Pressure and Lipids in Overweight and Obese Adolescents. PLoS ONE, 6(11). DOI: 10.1371/journal.pone.0026643
Carson, V., & Janssen, I. (2011) Volume, patterns, and types of sedentary behavior and cardio-metabolic health in children and adolescents: a cross-sectional study. BMC Public Health, 11(1), 274. DOI: 10.1186/1471-2458-11-274
Some exciting news this week - the world’s first systematic review on the relationship between sedentary behaviour and health in school-aged children has just been published online in the International Journal of Behavioural Nutrition and Physical Activity. I am one of 8 authors on the review (nestled nicely in the middle), which was created to inform the Canadian Sedentary Behaviour Guidelines, released earlier this year.... Read more »
Tremblay, M., LeBlanc, A., Kho, M., Saunders, T., Larouche, R., Colley, R., Goldfield, G., & Connor Gorber, S. (2011) Systematic review of sedentary behaviour and health indicators in school-aged children and youth. International Journal of Behavioral Nutrition and Physical Activity, 8(1), 98. DOI: 10.1186/1479-5868-8-98
by Travis Saunders, MSc, CEP in Obesity Panacea
Image by mhowry
Travis’ Note: Today’s post comes from PhD Student Ash Routen. You can find out more about Ash and his work at the bottom of this post.
Consistent with the majority of developed countries, a significant proportion of children here in the UK are overweight or obese (around 30% of 10-11 year olds as of 2010). How do we know this? Well, since 2005 the UK Department of Health have been operating the ‘National Child Measurement Programme’ (NCMP) a nationwide public he........ Read more »
Routen, A., Edwards, M., Upton, D., & Peters, D. (2011) The impact of school-day variation in weight and height on National Child Measurement Programme body mass index-determined weight category in Year 6 children. Child: Care, Health and Development, 37(3), 360-367. DOI: 10.1111/j.1365-2214.2010.01204.x
by Travis Saunders, MSc, CEP in Obesity Panacea
Earlier this year I posted an infographic on the health impact of sedentary behaviour which has generated plenty of discussion both here and elsewhere. Many people are understandably skeptical about the relationship between sedentary behaviour and mortality, so I was excited about the recent publication of two recent systematic reviews focusing on just this issue.
The first, published in the American Journal of Preventive Medicine by Karin Proper and colleagues, focused on the prospective a........ Read more »
Proper, K., Singh, A., van Mechelen, W., & Chinapaw, M. (2011) Sedentary Behaviors and Health Outcomes Among Adults. American Journal of Preventive Medicine, 40(2), 174-182. DOI: 10.1016/j.amepre.2010.10.015
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