Showing papers by "David W. Dunstan published in 2010"
TL;DR: Sitting time, TV time, and time sitting in automobiles increase premature mortality risk, and breaking up sedentary time is beneficial.
Abstract: Even when adults meet physical activity guidelines, sitting for prolonged periods can compromise metabolic health Television (TV) time and objective measurement studies show deleterious associations, and breaking up sedentary time is beneficial Sitting time, TV time, and time sitting in automobiles increase premature mortality risk Further evidence from prospective studies, intervention trials, and population-based behavioral studies is required
2,054 citations
TL;DR: Television viewing time was associated with increased risk of all-cause and CVD mortality, and chronic disease prevention strategies could focus on reducing sitting time, particularly prolonged television viewing.
Abstract: Background— Television viewing time, the predominant leisure-time sedentary behavior, is associated with biomarkers of cardiometabolic risk, but its relationship with mortality has not been studied. We examined the associations of prolonged television viewing time with all-cause, cardiovascular disease (CVD), cancer, and non-CVD/noncancer mortality in Australian adults. Methods and Results— Television viewing time in relation to subsequent all-cause, CVD, and cancer mortality (median follow-up, 6.6 years) was examined among 8800 adults ≥25 years of age in the Australian Diabetes, Obesity and Lifestyle Study (AusDiab). During 58 087 person-years of follow-up, there were 284 deaths (87 CVD deaths, 125 cancer deaths). After adjustment for age, sex, waist circumference, and exercise, the hazard ratios for each 1-hour increment in television viewing time per day were 1.11 (95% confidence interval [CI], 1.03 to 1.20) for all-cause mortality, 1.18 (95% CI, 1.03 to 1.35) for CVD mortality, and 1.09 (95% CI, 0.96 ...
792 citations
01 Dec 2010
TL;DR: Comparing epidemiologic evidence suggests that the metabolic and long-term health consequences of habitual sedentary behavior (too much sitting) are distinct from those associated with a lack of moderate-to-vigorous activity (too little exercise).
Abstract: Compared with our parents or grandparents, we are spending increasing amounts of time in environments that not only limit physical activity but require prolonged sitting—at work, at home, and in our cars and communities.1 Work sites, schools, homes, and public spaces have been (and continue to be) re-engineered in ways that minimize human movement and muscular activity. These changes have a dual effect on human behavior: people move less and sit more. From an evolutionary perspective, humans were designed to move—to locomote and engage in all manner of manual labor throughout the day. This was essential to our survival as a species. The recent shift from a physically demanding life to one with few physical challenges has been sudden, occurring during a tiny fraction of human existence.
Societal indicators of reductions in human energy expenditure and increases in sedentary behavior during the past several decades are particularly striking. In 1970, 2 in 10 working Americans were in jobs requiring only light activity (predominantly sitting at a desk), whereas 3 in 10 were in jobs requiring high-energy output (eg, construction, manufacturing, farming).2 By 2000, more than 4 in 10 adults were in light-activity jobs, whereas 2 in 10 were in high-activity jobs.2 Moreover, during the past 20 years, total screen time (ie, using computers, watching television, playing video games) has increased dramatically. In 2003, nearly 6 in 10 working adults used a computer on the job and more than 9 in 10 children used computers in school (kindergarten through grade 12).3 Between 1989 and 2009, the number of households with a computer and Internet access increased from 15% to 69%.3 Other significant contributors to daily sitting time—watching television and driving personal vehicles—are at all-time highs, with estimates of nearly 4 hours and 1 hour, respectively.4,5
Scientists studying the ill effects of this decrease in physical activity have revealed a complex, multifaceted relationship among physical work, energy expenditure, and health.6,7 Clinical and basic research has focused on the benefits of incorporating regular bouts of exercise into modern life to adjust to some extent for the loss of the physically active life led by our ancestors.6 Current public health recommendations propose engaging in at least 150 minutes per week of moderate-to-vigorous activity to help prevent and manage multiple chronic conditions, notably cardiovascular disease, type 2 diabetes, obesity, and some cancers.7 The evidence base that supports this exercise recommendation is substantial. (Here, we use the terms exercise and moderate-to-vigorous activity interchangeably, recognizing that, by some definitions, exercise refers specifically to intentional activity carried out for health/fitness purposes.7)
Those who do not exercise have by convention been termed sedentary. However, this is no longer an adequate perspective. Recent epidemiologic evidence suggests that the metabolic and long-term health consequences of habitual sedentary behavior (too much sitting) are distinct from those associated with a lack of moderate-to-vigorous activity (too little exercise).8,9 This shift in perspective is being clarified through innovations in technology used to characterize movement patterns in populations.
702 citations
TL;DR: Limited evidence was found to support a positive relationship between occupational sitting and health risks, and the heterogeneity of study designs, measures, and findings makes it difficult to draw definitive conclusions at this time.
478 citations
TL;DR: In women and men, sitting time and TV viewing time were deleteriously associated with cardio-metabolic risk biomarkers, with sitting time having more consistent associations in both sexes and being independent of central adiposity.
Abstract: We examined the associations of sitting time and television (TV) viewing time with continuously measured biomarkers of cardio-metabolic risk in Australian adults. Waist circumference, BMI, resting blood pressure, triglycerides, HDL cholesterol, fasting and 2-h postload plasma glucose, and fasting insulin were measured in 2,761 women and 2,103 men aged ≥30 years (mean age 54 years) without clinically diagnosed diabetes from the 2004-2005 Australian Diabetes, Obesity and Lifestyle (AusDiab) study. Multivariate linear regression analyses examined associations of self-reported sitting time and TV viewing time (hours per day) with these biomarkers, adjusting for potential confounding variables. For both women and men, sitting time was detrimentally associated with waist circumference, BMI, systolic blood pressure, fasting triglycerides, HDL cholesterol, 2-h postload plasma glucose, and fasting insulin (all P
267 citations
TL;DR: There is a dearth of evidence on the effectiveness of workplace interventions for reducing sitting in light of the growing body of evidence that prolonged sitting is negatively associated with health, which highlights a gap in the scientific literature that needs to be addressed.
255 citations
TL;DR: Increasing moderate-to-vigorous and light intensity physical activity, and decreasing sedentary time, may assist with weight management and improve other metabolic health outcomes for breast cancer survivors.
Abstract: Obesity and physical inactivity are poor prognostic indicators for breast cancer. Studies to date have relied on self-report measures of physical activity, which tend mainly to assess moderate-to-vigorous intensity leisure-time physical activity. We report the cross-sectional associations of objectively assessed physical activity and sedentary time with adiposity in a sample of breast cancer survivors from the United States. One hundred and eleven women from the National Health and Nutrition Examination Survey (NHANES) 2003–2004 and 2005–2006 reported a history of breast cancer. Participants wore an accelerometer for 7 days, and activity levels were summarized as moderate-to-vigorous intensity (accelerometer counts/min ≥1,952), light intensity (counts/min 100–1,951), and sedentary time (counts/min <100). Anthropometric measures were taken by study staff at examination centers. Participants spent the majority of their day in sedentary time (66%) or in light intensity activities (33%). Log moderate-to-vigorous intensity physical activity was negatively associated with adiposity (waist circumference β = −9.805 [95% CI: −15.836, −3.775]; BMI β = −3.576 [95% CI: −6.687, −0.464]). Light intensity physical activity was negatively associated with adiposity; however, the fully adjusted models did not retain statistical significance. Similarly, sedentary time was positively associated with adiposity, but the fully adjusted models were not statistically significant. This is the first study to describe the objectively assessed physical activity and sedentary time of breast cancer survivors. Increasing moderate-to-vigorous and light intensity physical activity, and decreasing sedentary time, may assist with weight management and improve other metabolic health outcomes for breast cancer survivors.
216 citations
TL;DR: Wijdele et al. as discussed by the authors examined whether changes in self-reported television viewing time are associated with changes in continuous biomarkers of cardiometabolic risk (waist circumference, triglycerides, HDL-cholesterol, systolic and diastolic blood pressure, fasting plasma glucose, and a clustered risk score).
Abstract: WIJNDAELE, K., G. N. HEALY, D. W. DUNSTAN, A. G. BARNETT, J. SALMON, J. E. SHAW, P. Z. ZIMMET, and N. OWEN. Increased Cardiometabolic Risk Is Associated with Increased TV Viewing Time. Med. Sci. Sports Exerc., Vol. 42, No. 8, pp. 1511‐1518, 2010. Purpose: Television viewing time, independent of leisure time physical activity, has cross-sectional relationships with the metabolic syndrome and its individual components. We examined whether baseline and 5-yr changes in self-reported television viewing time are associated with changes in continuous biomarkers of cardiometabolic risk (waist circumference, triglycerides, HDLcholesterol, systolic and diastolic blood pressure, fasting plasma glucose, and a clustered cardiometabolic risk score) in Australian adults. Methods: The Australian Diabetes, Obesity and Lifestyle Study (AusDiab) is a prospective, population-based cohort study with biological, behavioral, and demographic measures collected in 1999‐2000 and 2004‐2005. Noninstitutionalized adults aged Q25 yr were measured at baseline (11,247; 55% of those completing an initial household interview); 6400 took part in the 5-yr follow-up biomedical examination, and 3846 met the inclusion criteria for this analysis. Multiple linear regression analysis was used, and unstandardized B coefficients (95% confidence intervals (CI)) are provided. Results: Baseline television viewing time (10 hIwk j1 unit) was not significantly associated with change in any of the biomarkers of cardiometabolic risk. Increases in television viewing time over 5 yr (10 hIwk j1 unit) were associated with increases in waist circumference (men: 0.43 cm, 95% CI = 0.08‐0.78 cm, P = 0.02; women: 0.68 cm, 95% CI = 0.30‐1.05, P G 0.001), diastolic blood pressure (women: 0.47 mm Hg, 95% CI = 0.02‐0.92 mm Hg, P = 0.04), and the clustered cardiometabolic risk score (women: 0.03, 95% CI = 0.01‐0.05, P = 0.007). These associations were independent of baseline television viewing time and baseline and change in physical activity and other potential confounders. Conclusions: These findings indicate that an increase in television viewing time is associated with adverse cardiometabolic biomarker changes. Further prospective studies using objective measures of several sedentary behaviors are required to confirm causality of the associa
157 citations
TL;DR: For example, this paper examined the associations between two indicators of socio-economic position (education and household income) and biomarkers of diabetes and cardiovascular disease (CVD) for men and women in a national, population-based study of 11,247 Australian adults.
136 citations
TL;DR: Prolonged TV time is associated with indices of social disadvantage and older age, and these findings can inform the understanding of potential contextual influences and guide preventive initiatives.
Abstract: Background:Sedentary behaviors, particularly television viewing (TV) time, are associated with adverse health outcomes in adults, independent of physical activity levels. These associations are stronger and more consistent for women than for men. Methods:Multivariate regression models examined the sociodemographic correlates of 2 categories of TV time (≥2 hours/day and ≥4 hours/day); in a large, population-based sample of Australian adults (4950 men, 6001 women; mean age 48.1 years, range 25–91) who participated in the 1999/2000 Australian Diabetes, Obesity, and Lifestyle (AusDiab) study. Results:Some 46% of men and 40% of women watched ≥ 2 hours TV/day; 9% and 6% respectively watched ≥ 4 hours/day. For both men and women, ≥2 hours TV/day was associated with less than tertiary education, living outside of state capital cities, and having no paid employment. For women, mid and older age (45−64 and 65+) were also significant correlates of ≥2 hours TV/day. Similar patterns of association were observed in tho...
99 citations
TL;DR: Subgroups with the highest proportions of people watching >14 hours/week of TV were identified and described using a combination of demographic, health and mental health, and behavioral variables to help inform intervention development in this increasingly important behavioral health area.
Journal Article•
01 Jan 2010-Centre for Health Research; Faculty of Health; Institute of Health and Biomedical Innovation
TL;DR: This is the first study to evaluate the telephone as the primary method of delivering a behavioural weight loss intervention in type 2 diabetes, and the inclusion of a cost-effectiveness analysis will advance the science of broad reach approaches to weight control and health behaviour change.
Abstract: Background
By 2025, it is estimated that approximately 1.8 million Australian adults (approximately 8.4% of the adult population) will have diabetes, with the majority having type 2 diabetes. Weight management via improved physical activity and diet is the cornerstone of type 2 diabetes management. However, the majority of weight loss trials in diabetes have evaluated short-term, intensive clinic-based interventions that, while producing short-term outcomes, have failed to address issues of maintenance and broad population reach. Telephone-delivered interventions have the potential to address these gaps.
Methods/Design
Using a two-arm randomised controlled design, this study will evaluate an 18-month, telephone-delivered, behavioural weight loss intervention focussing on physical activity, diet and behavioural therapy, versus usual care, with follow-up at 24 months. Three-hundred adult participants, aged 20-75 years, with type 2 diabetes, will be recruited from 10 general practices via electronic medical records search. The Social-Cognitive Theory driven intervention involves a six-month intensive phase (4 weekly calls and 11 fortnightly calls) and a 12-month maintenance phase (one call per month). Primary outcomes, assessed at 6, 18 and 24 months, are: weight loss, physical activity, and glycaemic control (HbA1c), with weight loss and physical activity also measured at 12 months. Incremental cost-effectiveness will also be examined. Study recruitment began in February 2009, with final data collection expected by February 2013.
Discussion
This is the first study to evaluate the telephone as the primary method of delivering a behavioural weight loss intervention in type 2 diabetes. The evaluation of maintenance outcomes (6 months following the end of intervention), the use of accelerometers to objectively measure physical activity, and the inclusion of a cost-effectiveness analysis will advance the science of broad reach approaches to weight control and health behaviour change, and will build the evidence base needed to advocate for the translation of this work into population health practice.
TL;DR: In this article, the authors evaluated an 18-month telephone-delivered, behavioural weight loss intervention focussing on physical activity, diet and behavioural therapy, versus usual care, with follow-up at 24 months.
Abstract: By 2025, it is estimated that approximately 18 million Australian adults (approximately 84% of the adult population) will have diabetes, with the majority having type 2 diabetes Weight management via improved physical activity and diet is the cornerstone of type 2 diabetes management However, the majority of weight loss trials in diabetes have evaluated short-term, intensive clinic-based interventions that, while producing short-term outcomes, have failed to address issues of maintenance and broad population reach Telephone-delivered interventions have the potential to address these gaps Using a two-arm randomised controlled design, this study will evaluate an 18-month, telephone-delivered, behavioural weight loss intervention focussing on physical activity, diet and behavioural therapy, versus usual care, with follow-up at 24 months Three-hundred adult participants, aged 20-75 years, with type 2 diabetes, will be recruited from 10 general practices via electronic medical records search The Social-Cognitive Theory driven intervention involves a six-month intensive phase (4 weekly calls and 11 fortnightly calls) and a 12-month maintenance phase (one call per month) Primary outcomes, assessed at 6, 18 and 24 months, are: weight loss, physical activity, and glycaemic control (HbA1c), with weight loss and physical activity also measured at 12 months Incremental cost-effectiveness will also be examined Study recruitment began in February 2009, with final data collection expected by February 2013 This is the first study to evaluate the telephone as the primary method of delivering a behavioural weight loss intervention in type 2 diabetes The evaluation of maintenance outcomes (6 months following the end of intervention), the use of accelerometers to objectively measure physical activity, and the inclusion of a cost-effectiveness analysis will advance the science of broad reach approaches to weight control and health behaviour change, and will build the evidence base needed to advocate for the translation of this work into population health practice ACTRN12608000203358
TL;DR: The basic partition model applied in the analyses has limitations with respect to not being able to account for total activity time, but as a potential explanation of the relationship between television viewing time and mortality, the “displacement” hypothesis is intriguing.
Abstract: We thank Drs Ding, Mekary, and Katz for their interest in our recent findings showing a positive association between television viewing time and mortality.1 Drs Ding and Mekary helpfully bring to our attention the relevance of their isotemporal substitution model to our findings. Consistent with their perspective, we acknowledge that the basic partition model applied in our analyses has limitations with respect to not being able to account for total activity time. As a potential explanation of the relationship between television viewing time and mortality, their “displacement” hypothesis is intriguing. However, as noted in our article, we and others, including Mekary et al,2 have previously shown television viewing time to be …
TL;DR: Television viewing was significantly associated with increased odds of prevalent albuminuria and low estimated glomerular filtration rate and in the gender-stratified analyses this pattern was seen for men, but not for women.
Abstract: Background
Television viewing time independent of physical activity is associated with a number of chronic diseases and related risk factors; however, its relationship with chronic kidney disease is unknown.
TL;DR: Elevated 2-h PG levels and pre-diabetes were inversely associated with low trauma and/or all fractures in non-diabetic women, independent of BMI and fasting insulin levels.
Abstract: Summary
The association between pre-diabetes and fracture risk remains unclear. In this large cohort of middle-aged and older Australian men and women without diabetes, elevated 2-h plasma glucose and pre-diabetes were associated with a reduced 5-year risk of low trauma and all fractures in women, independently of BMI, fasting insulin and other lifestyle factors.
TL;DR: This paper puts forward an innovative model providing a framework for understanding some of the physio logical consequences of sedentary behavior, and argues that the model must be considered in a broader context, taking into account how sedentarybehavior can coexist with high levels of both physical activity and cardio‐ respiratory fitness.
Abstract: we read with great interest the Perspectives article from Charansonney and Després in the august 2010 issue of Nature Reviews Cardio logy (Charansonney, O. L. & Després, J. ‐P. Disease prevention—should we target obesity or sedentary lifestyle? Nat. Rev. Cardiol. 7, 468–472 (2010)).1 this paper puts forward an innovative model providing a framework for understanding some of the physio logical consequences of sedentary behavior. we agree with many aspects of what is proposed. However, as the group that has conducted many of the initial studies identifying the unique health consequences of sedentary behavior, we are concerned that aspects of the Charansonney and Després model might perpetuate the misconception that sedentary behavior is simply ‘one end of the physical activity continuum’. that is, people can be classified as either ‘active’ or ‘sedentary’ based on their self‐reported or objectively assessed physical activity. the contemporary understanding of seden tary behavior is that it is not merely the absence of health‐enhancing physical acti‐ vity in everyday life. sedentary behavior is charac terized by prolonged sitting or reclin‐ ing and the absence of whole‐body move‐ ment. sedentary behavior has deleterious health consequences that are distinct from the lack of physical activity of moderate‐ to‐vigorous intensity. Put simply, sedentary behavior and physical inactivity are two sep‐ arate and indepen dent attributes, each with distinct health consequences. in their model, Charansonney and Després propose that individuals who have a seden‐ tary lifestyle exhibit a hypothesized inappro‐ priate stress response, whereas those who have an active lifestyle are not exposed to the cascade of deleterious effects. However, we have demonstrated significant, detrimen‐ tal associations of sedentary behavior with a range of cardiometabolic biomarkers in adults meeting physical activity guidelines.2 the Charansonney and Després model does not account for the fact that many people who engage in vigorous‐intensity physical activity on a daily basis, and hence have high levels of cardio respiratory fitness, also engage in prolonged periods of sitting throughout their day. we believe that model put forward by Charansonney and Després supports a strong potential biological plausibility for many of the deleterious associations that we and others have shown to be associated with sedentary behavior. However, we would argue that the model must be considered in a broader context, taking into account how sedentary behavior can coexist with high levels of both physical activity and cardio‐ respiratory fitness.
TL;DR: In this paper, the authors examined associations with physical activity at and around the workplace and found that those who perceived their work colleagues and managers to be physically active, and those who indicated that their workplace provides facilities to support them being active had higher odds of being physically active at or around their workplace.
Abstract: Purpose – The workplace is an ideal setting to promote physical activity. The purpose of this study is to examine associations with physical activity at and around the workplace.Design/methodology/approach – Participants were recruited from a random sample of employed adults (n=1,107) in capital cities and major regional centres in Australia. Self‐reported barriers and participation in physical activity at and around the workplace were assessed. A multivariable logistic regression model adjusting for age, sex, occupational status, and overall physical activity assessed the odds of being active in this setting.Findings – Of participants, 61 percent perceived being active in the workplace. Those who perceived their work colleagues and managers to be physically active, and those who indicated that their workplace provides facilities to support them being active had higher odds of being physically active at or around the workplace.Research limitations/implications – A poor response rate, physically active sam...
TL;DR: Following adjustment for sociodemographic and behavioral factors, there were few differences in barriers to physical activity between those with and without AGM, even after stratifying according toPhysical activity.
Abstract: PurposeThe purpose of this study was to examine perceived barriers to physical activity among adults with and without abnormal glucose metabolism (AGM), and whether barriers varied according to phy...
Journal Article•
Journal Article•