Reducing office workers' sitting time: rationale and study design for the Stand Up Victoria cluster randomized trial

Background

Excessive time spent in sedentary behaviours (sitting or lying with low energy expenditure) is associated with an increased risk for type 2 diabetes, cardiovascular disease and some cancers. Desk-based office workers typically accumulate high amounts of daily sitting time, often in prolonged unbroken bouts. The Stand Up Victoria study aims to determine whether a 3-month multi-component intervention in the office setting reduces workplace sitting, particularly prolonged, unbroken sitting time, and results in improvements in cardio-metabolic biomarkers and work-related outcomes, compared to usual practice.

Methods/Design

A two-arm cluster-randomized controlled trial (RCT), with worksites as the unit of randomization, will be conducted in 16 worksites located in Victoria, Australia. Work units from one organisation (Department of Human Services, Australian Government) will be allocated to either the multi-component intervention (organisational, environmental [height-adjustable workstations], and individual behavioural strategies) or to a usual practice control group. The recruitment target is 160 participants (office-based workers aged 18–65 years and working at least 0.6 full time equivalent) per arm. At each assessment (0- [baseline], 3- [post intervention], and 12-months [follow-up]), objective measurement via the activPAL3 activity monitor will be used to assess workplace: sitting time (primary outcome); prolonged sitting time (sitting time accrued in bouts of ≥30 minutes); standing time; sit-to-stand transitions; and, moving time. Additional outcomes assessed will include: non-workplace activity; cardio-metabolic biomarkers and health indicators (including fasting glucose, lipids and insulin; anthropometric measures; blood pressure; and, musculoskeletal symptoms); and, work-related outcomes (presenteeism, absenteeism, productivity, work performance). Incremental cost-effectiveness and identification of both workplace and individual-level mediators and moderators of change will also be evaluated.

Discussion

Stand Up Victoria will be the first cluster-RCT to evaluate the effectiveness of a multi-component intervention aimed at reducing prolonged workplace sitting in office workers. Strengths include the objective measurement of activity and assessment of the intervention on markers of cardio-metabolic health. Health- and work-related benefits, as well as the cost-effectiveness of the intervention, will help to inform future occupational practice.

Trial registration

ACTRN1211000742976

Joint associations of poor diet quality and prolonged television viewing time with abnormal glucose metabolism in Australian men and women

OBJECTIVE

To examine the independent and joint associations of diet quality and television viewing time with abnormal glucose metabolism (AGM) in men and women.

METHOD

Cross-sectional data from 5346 women and 4344 men from the 1999 to 2000 Australian Diabetes, Obesity and Lifestyle Study were examined. Diet quality scores were derived from a food frequency questionnaire and categorised into tertiles (high; moderate; low). Television viewing time was dichotomised into low (≤ 14 h/week) and high (>14 h/week). AGM was defined as impaired fasting glucose, impaired glucose tolerance, known or newly diagnosed diabetes based on an oral glucose tolerance test. Regression analyses were adjusted for confounding variables.

RESULTS

Diet quality and television viewing time were significantly associated with AGM in women, independent of waist circumference. Compared to women with high diet quality/low television viewing time, women with low diet quality/low television viewing time and women with low diet quality/high television viewing time were significantly more likely to have AGM. Associations were not observed in men.

CONCLUSIONS

Both poor diet quality and prolonged television viewing should be addressed to reduce risk of AGM in women. Further understanding of modifiable risk factors in men is warranted.

Initiating and maintaining recreational walking: a longitudinal study on the influence of neighborhood green space

OBJECTIVE

This study examined prospective relationships of green space attributes with adults initiating or maintaining recreational walking.

METHODS

Postal surveys were completed by 1036 adults living in Adelaide, Australia, at baseline (two time points in 2003-04) and follow-up (2007-08). Initiating or maintaining recreational walking was determined using self-reported walking frequency. Green space attributes examined were perceived presence, quality, proximity, and the objectively measured area (total and largest) and number of green spaces within a 1.6 km buffer drawn from the center of each study neighborhood. Multilevel regression analyses examined the odds of initiating or maintaining walking separately for each green space attribute.

RESULTS

At baseline, participants were categorized into non-regular (n = 395), regular (n = 286), and irregular walkers (n = 313). Among non-regular walkers, 30% had initiated walking, while 70% of regular walkers had maintained walking at follow-up. No green space attributes were associated with initiating walking. However, positive perceptions of the presence of and proximity to green spaces and the total and largest areas of green space were significantly associated with a higher likelihood of walking maintenance over four years.

CONCLUSION

Neighborhood green spaces may not assist adults to initiate walking, but their presence and proximity may facilitate them to maintain recreational walking over time.

Independent and joint associations of TV viewing time and snack food consumption with the metabolic syndrome and its components; a cross-sectional study in Australian adults

Background

Television (TV) viewing time is positively associated with the metabolic syndrome (MetS) in adults. However, the mechanisms through which TV viewing time is associated with MetS risk remain unclear. There is evidence that the consumption of energy-dense, nutrient poor snack foods increases during TV viewing time among adults, suggesting that these behaviors may jointly contribute towards MetS risk. While the association between TV viewing time and the MetS has previously been shown to be independent of adult’s overall dietary intake, the specific influence of snack food consumption on the relationship is yet to be investigated. The purpose of this study was to examine the independent and joint associations of daily TV viewing time and snack food consumption with the MetS and its components in a sample of Australian adults.

Methods

Population-based, cross-sectional study of 3,110 women and 2,572 men (>35 years) without diabetes or cardiovascular disease. Participants were recruited between May 1999 and Dec 2000 in the six states and the Northern Territory of Australia. Participants were categorised according to self-reported TV viewing time (low: 0-2 hr/d; high: >2 hr/d) and/or consumption of snack foods (low: 0-3 serves/d; high: >3 serves/d). Multivariate odds ratios [95% CI] for the MetS and its components were estimated using gender-specific, forced entry logistic regression.

Results

OR [95% CI] for the MetS was 3.59 [2.25, 5.74] (p≤0.001) in women and 1.45 [1.02, 3.45] (p = 0.04) in men who jointly reported high TV viewing time and high snack food consumption. Obesity, insulin resistance and hypertension (women only) were also jointly associated with high TV viewing time and high snack food consumption. Further adjustment for diet quality and central adiposity maintained the associations in women. High snack food consumption was also shown to be independently associated with MetS risk [OR: 1.94 (95% CI: 1.45, 2.60), p < 0.001] and hypertension [OR: 1.43 (95% CI: 1.01, 2.02), p = 0.05] in women only. For both men and women, high TV viewing time was independently associated with the MetS and its individual components (except hypertension).

Conclusion

TV viewing time and snack food consumption are independently and jointly associated with the MetS and its components, particularly in women. In addition to physical activity, population strategies targeting MetS prevention should address high TV time and excessive snack food intake.

Reducing sitting time in office workers: short-term efficacy of a multicomponent intervention

OBJECTIVE

To investigate the short-term efficacy of a multicomponent intervention to reduce office workers' sitting time.

METHODS

Allocation for this non-randomized controlled trial (n=43 participants; 56% women; 26-62 years; Melbourne, Australia) was by office floor, with data collected during July-September 2011. The 4-week intervention emphasized three key messages: "Stand Up, Sit Less, Move More" and comprised organizational, environmental, and individual elements. Changes in minutes/day at the workplace spent sitting (primary outcome), in prolonged sitting (sitting time accumulated in bouts ≥ 30 min), standing, and moving were objectively measured (activPAL3).

RESULTS

Relative to the controls, the intervention group significantly reduced workplace sitting time (mean change [95%CI]: -125 [-161, -89] min/8-h workday), with changes primarily driven by a reduction in prolonged sitting time (-73 [-108, -40] min/8-h workday). Workplace sitting was almost exclusively replaced by standing (+127 [+92, +162] min/8-h workday) with non-significant changes to stepping time (-2 [-7, +4] min/8-h workday) and number of steps (-70 [-350, 210]).

CONCLUSIONS

This multicomponent workplace intervention demonstrated that substantial reductions in sitting time are achievable in an office setting. Larger studies with longer timeframes are needed to assess sustainability of these changes, as well as their potential longer-term impacts on health and work-related outcomes.

Associations of strength training with impaired glucose metabolism: the AusDiab Study

PURPOSE

To examine the association of strength training (ST) activity with impaired glucose metabolism (IGM) in Australian adults.

METHODS

On the basis of an oral glucose tolerance test, IGM (which includes impaired fasting glucose, impaired glucose tolerance, or newly diagnosed type 2 diabetes), was assessed in 5831 adults (mean age = 56.0 +/- 12.7 yr) without clinically diagnosed diabetes who participated in the 2004–2005 Australian Diabetes, Obesity and Lifestyle Study (AusDiab). Meeting the current ST guideline was based on reporting ST at least two times per week (frequency) or > or = 40 min x wk(-1) in total (duration). Multiple logistic regression analyses examined associations of self-reported ST frequency and duration with IGM.

RESULTS

After adjustment for known confounding factors and total moderate- to vigorous-intensity leisure time exercise, the odds ratio (OR) of IGM was 0.73 (95% confidence interval [CI] = 0.59–0.91, P < or = 0.005) in those who met the ST frequency guideline (two or more times per week) and 0.69 (95% CI = 0.55–0.87, P < or = 0.01) in those who met the ST duration guideline (> or =40 min x wk(-1)). Those who achieved both the recommended frequency and duration of ST had 24% lower odds of IGM. There was also evidence that a moderate frequency (once a week) and duration (10–39 min x wk(-1)) of ST reduced the odds of IGM (OR frequency = 0.53, 95% CI = 0.51–0.81, P e 0.01; OR duration = 0.72, 95% CI = 0.52–1.00, P < or = 0.05).

CONCLUSIONS

These findings support the importance of including ST activity, at a frequency of at least once per week, within exercise management recommendations for the maintenance of favorable metabolic health, particularly as it may contribute to reducing the risk of developing type 2 diabetes mellitus.

Sharing good NEWS across the world: developing comparable scores across 12 countries for the Neighborhood Environment Walkability Scale (NEWS)

BACKGROUND

The IPEN (International Physical Activity and Environment Network) Adult project seeks to conduct pooled analyses of associations of perceived neighborhood environment, as measured by the Neighborhood Environment Walkability Scale (NEWS) and its abbreviated version (NEWS-A), with physical activity using data from 12 countries. As IPEN countries used adapted versions of the NEWS/NEWS-A, this paper aimed to develop scoring protocols that maximize cross-country comparability in responses. This information is also highly relevant to non-IPEN studies employing the NEWS/NEWS-A, which is one of the most popular measures of perceived environment globally.

METHODS

The following countries participated in the IPEN Adult study: Australia, Belgium, Brazil, Colombia, Czech Republic, Denmark, Hong Kong, Mexico, New Zealand, Spain, the United Kingdom, and the United States. Participants (N = 14,305) were recruited from neighborhoods varying in walkability and socio-economic status. Countries collected data on the perceived environment using a self- or interviewer-administered version of the NEWS/NEWS-A. Confirmatory Factor Analysis (CFA) was used to derive comparable country-specific measurement models of the NEWS/NEWS-A. The level of correspondence between standard and alternative versions of the NEWS/NEWS-A factor-analyzable subscales was determined by estimating the correlations and mean standardized difference (Cohen's d) between them using data from countries that had included items from both standard and alternative versions of the subscales.

RESULTS

Final country-specific measurement models of the NEWS/NEWS-A provided acceptable levels of fit to the data and shared the same factorial structure with six latent factors and two single items. The correspondence between the standard and alternative versions of subscales of Land use mix - access, Infrastructure and safety for walking/cycling, and Aesthetics was high. The Brazilian version of the Traffic safety subscale was highly, while the Australian and Belgian versions were marginally, comparable to the standard version. Single-item versions of the Street connectivity subscale used in Australia and Belgium showed marginally acceptable correspondence to the standard version.

CONCLUSIONS

We have proposed country-specific modifications to the original scoring protocol of the NEWS/NEWS-A that enhance inter-country comparability. These modifications have yielded sufficiently equivalent measurement models of the NEWS/NEWS-A. Some inter-country discrepancies remain. These need to be considered when interpreting findings from different countries.

Correlates of prolonged television viewing time in older Japanese men and women

BACKGROUND

In addition to insufficient moderate-to-vigorous physical activity (MVPA), prolonged sitting time is also a health risk for older adults. An understanding of population subgroups who have prolonged television viewing (TV) time, a predominant sedentary behavior, can aid in the development of relevant health promotion initiatives; however, few such studies have focused on older adults, the most sedentary segment of the population as a whole. The aim of this study is to examine the socio-demographic attributes associated with TV time among community-dwelling Japanese older men and women.

METHODS

A population-based, cross-sectional mail survey was used to collect data on TV time, MVPA, and socio-demographic characteristics. The survey was conducted from February through March 2010. Participants were 2700 community-dwelling older adults (aged 65-74 years, 50% men) who were randomly selected from the registry of residential addresses of three cities in Japan. Data from 1665 participants (mean age: 69.5 years, 52% men) who completed all variables for the present study were analyzed. Multivariate logistic regression analyses were used to calculate the odds ratios (ORs) of prolonged TV time (>2 hours/day) for each socio-demographic attribute, stratified by gender.

RESULTS

Of the 1665 participants, 810 (48.6%) watched TV for more than 2 hours/day. The median television viewing time (25th, 75th percentile) was 2.00 (1.07, 3.50) hours/day. Prolonged TV time was associated with not in full-time employment, lower educational attainment, weight status, living in regional areas and low MVPA for the whole sample. For men, prolonged TV time was associated with lower educational attainment; (OR = 1.53, 95% CI: 1.12-2.07), underweight (OR = 1.63, 95% CI: 1.02-2.60), overweight (OR = 1.57, 95% CI: 1.11-2.21), and low MVPA (OR = 1.43, 95% CI: 1.02-2.02). For women, living in regional areas (OR = 2.02, 95% CI: 1.33-3.08), living alone (OR = 1.61, 95% CI: 1.03-2.49), not driving (OR = 1.79, 95% CI 1.21-2.65), overweight (OR = 1.50, 95% CI: 1.00-2.24), and low MVPA (OR = 1.51. 95% CI: 1.05-2.17) were associated with prolonged TV time.

CONCLUSIONS

These findings identify particular socio-demographic and behavioral characteristics related to TV time among Japanese older adults. It should be noted that correlates of prolonged TV time differed by gender. Women in living situations with limited transportation options tended to spend prolonged time watching TV. Health promotion initiatives for older adults, particularly for older women, may be more effective if they take these attributes into account.

Television viewing time and reduced life expectancy: a life table analysis

BACKGROUND

Prolonged television (TV) viewing time is unfavourably associated with mortality outcomes, particularly for cardiovascular disease, but the impact on life expectancy has not been quantified. The authors estimate the extent to which TV viewing time reduces life expectancy in Australia, 2008.

METHODS

The authors constructed a life table model that incorporates a previously reported mortality risk associated with TV time. Data were from the Australian Bureau of Statistics and the Australian Diabetes, Obesity and Lifestyle Study, a national population-based observational survey that started in 1999-2000. The authors modelled impacts of changes in population average TV viewing time on life expectancy at birth.

RESULTS

The amount of TV viewed in Australia in 2008 reduced life expectancy at birth by 1.8 years (95% uncertainty interval (UI): 8.4 days to 3.7 years) for men and 1.5 years (95% UI: 6.8 days to 3.1 years) for women. Compared with persons who watch no TV, those who spend a lifetime average of 6 h/day watching TV can expect to live 4.8 years (95% UI: 11 days to 10.4 years) less. On average, every single hour of TV viewed after the age of 25 reduces the viewer's life expectancy by 21.8 (95% UI: 0.3-44.7) min. This study is limited by the low precision with which the relationship between TV viewing time and mortality is currently known.

CONCLUSIONS

TV viewing time may be associated with a loss of life that is comparable to other major chronic disease risk factors such as physical inactivity and obesity.

Effects of breaking up prolonged sitting on skeletal muscle gene expression

Breaking up prolonged sitting has been beneficially associated with cardiometabolic risk markers in both observational and intervention studies. We aimed to define the acute transcriptional events induced in skeletal muscle by breaks in sedentary time. Overweight/obese adults participated in a randomized three-period, three-treatment crossover trial in an acute setting. The three 5-h interventions were performed in the postprandial state after a standardized test drink and included seated position with no activity and seated with 2-min bouts of light- or moderate-intensity treadmill walking every 20 min. Vastus lateralis biopsies were obtained in eight participants after each treatment, and gene expression was examined using microarrays validated with real-time quantitative PCR. There were 75 differentially expressed genes between the three conditions. Pathway analysis indicated the main biological functions affected were related to small-molecule biochemistry, cellular development, growth and proliferation, and carbohydrate metabolism. Interestingly, differentially expressed genes were also linked to cardiovascular disease. For example, relative to prolonged sitting, activity bouts increased expression of nicotamide N-methyltransferase, which modulates anti-inflammatory and anti-oxidative pathways and triglyceride metabolism. Activity bouts also altered expression of 10 genes involved in carbohydrate metabolism, including increased expression of dynein light chain, which may regulate translocation of the GLUT-4 glucose transporter. In addition, breaking up sedentary time reversed the effects of chronic inactivity on expression of some specific genes. This study provides insight into the muscle regulatory systems and molecular processes underlying the physiological benefits induced by interrupting prolonged sitting.

Sedentary behavior: understanding and influencing adults' prolonged sitting time

Too much sitting is now understood to be a health risk that is additional to, and distinct from, too little exercise. There is a rapidly-accumulating evidence on relationships of prolonged sedentary time and patterns of sedentary time with cardio-metabolic risk biomarkers and health outcomes. There is, however, the need to gather dose-response evidence and develop a broader understanding of the set of mechanisms linking sedentary behavior to health outcomes. In addition to the further understanding of the associated health risks, there is a new health-behavior, and epidemiological and experimental research agenda to be pursued, which include measurement studies; understanding the relevant determinants-particularly environmental determinants of sedentary behavior; and, developing effective interventions. A broad-based body of evidence is needed to inform the research-translation agenda-identifying and developing the future public health initiatives, environmental and policy changes and clinical guidelines that may be required.

Walkable area within which destinations matter: differences between Australian and Japanese cities

Adults' walking for transport is important for health benefits and can be associated with availability of destinations such as shops and services within a walking distance of 10 to 15 minutes from home. However, relevant evidence is mostly from Western countries. This study examined associations of destinations with walking for transport in Australian and Japanese cities. Data were collected from Adelaide, Australia (n = 2508), and 4 Japanese cities (n = 1285). Logistic regressions examined associations of self-reported walking for transport with the number of destination types within walk-distance categories. Walking was significantly associated with the number of destination types within a 10-minute walk from home for Australia and with the number of destination types within a 6- to 20-minute walk for Japan. Further research is needed on why walking by residents of Japanese cities can be influenced by more distant local destinations than in Australia to inform physical activity-related environmental and policy initiatives.

Destination and route attributes associated with adults' walking: a review

BACKGROUND

Increasing adults' physical activity through environmental initiatives that promote walking as a public health priority. To this end, evidence relevant to the urban planning and transport sectors is required. This review synthesized findings on destination and route attributes associated with utilitarian and recreational walking.

METHODS

A literature search was conducted in April 2011 using Web of Science, PubMed, Transport Research Information Services, GEOBASE, and SPORTDiscus. Environmental attributes were classified into the domains of utilitarian and recreational destinations (presence, proximity, quality) and route (sidewalks, connectivity, aesthetics, traffic, safety). Forty-six studies examining associations of these attributes with utilitarian and/or recreational walking were identified. Specific destination and route attributes associated with each type of walking were summarized.

RESULTS

Adults' utilitarian walking was consistently associated with presence and proximity of retail and service destinations (in 80% of the studies reviewed). It was also associated with functional aspects of routes (sidewalks and street connectivity) in 50% of studies. Recreational walking was associated with presence, proximity, and quality of recreational destinations (35% of studies) and route aesthetic (35% of studies). Both types of walking were found unrelated to route safety and traffic in most studies.

CONCLUSIONS

There is consistent evidence that better access to relevant neighborhood destinations (e.g., local stores, services, transit stops) can be conducive to adults' utilitarian walking. Some evidence also suggests that availability of sidewalks and well-connected streets can facilitate utilitarian walking. To better inform initiatives to promote adults' walking in the planning and transport sectors, future studies need to examine how accessible such destinations should be, as well as the effect of the quality of recreational destinations.