Linear and non-linear associations of device-measured sedentary time with older adults' skeletal muscle mass

BACKGROUND

Time spent sitting is associated adversely with health outcomes in older adults. Nevertheless, it is not clear how sedentary time may be related to appendicular skeletal muscle mass (ASM) - a key attribute of sarcopenia. This cross-sectional study examined associations of total sedentary time with ASM among community-dwelling older Japanese males and females.

METHODS

Participants (n = 281, 74.3 ± 5.2 yr) wore a tri-axial accelerometer for seven days. Body mass index-adjusted ASM (kg/BMI) was derived from bioimpedance measures. Multivariate linear and quadratic regression models examined the associations of ASM with total sedentary time, stratified by sex. Restricted cubic spline models were fitted to estimate non-linear associations. Isotemporal substitution (IS) models were used to estimate the impacts of replacing 30-minute of sedentary time with light physical activity (LPA) and moderate-to-vigorous physical activity (MVPA).

RESULTS

After adjustment, total sedentary time had a significant linear and negative association with ASM among females (β = -0.014; p = 0.023). For males, total sedentary time had a significant quadratic association (p = 0.020). Spline models indicated a reverse U-shaped association (p < 0.001) with total sedentary time over 9.3 h/day being associated with lower ASM. The IS models indicated that replacing 30 min/day of sedentary time with LPA would be positively and significantly associated with older females' ASM (β = 0.007, p = 0.022).

CONCLUSIONS

In older Japanese adults, higher volumes of time spent sedentary were associated with lower ASM. For males, only very high volumes of sedentary time appeared to be detrimental. These adverse relationships may in part be offset by more time spent in either LPA or MVPA.

Determining thresholds for spatial urban design and transport features that support walking to create healthy and sustainable cities: findings from the IPEN Adult study

An essential characteristic of a healthy and sustainable city is a physically active population. Effective policies for healthy and sustainable cities require evidence-informed quantitative targets. We aimed to identify the minimum thresholds for urban design and transport features associated with two physical activity criteria: at least 80% probability of engaging in any walking for transport and WHO's target of at least 15% relative reduction in insufficient physical activity through walking. The International Physical Activity and the Environment Network Adult (known as IPEN) study (N=11 615; 14 cities across ten countries) provided data on local urban design and transport features linked to walking. Associations of these features with the probability of engaging in any walking for transport and sufficient physical activity (≥150 min/week) by walking were estimated, and thresholds associated with the physical activity criteria were determined. Curvilinear associations of population, street intersection, and public transport densities with walking were found. Neighbourhoods exceeding around 5700 people per km², 100 intersections per km², and 25 public transport stops per km² were associated with meeting one or both physical activity criteria. Shorter distances to the nearest park were associated with more physical activity. We use the results to suggest specific target values for each feature as benchmarks for progression towards creating healthy and sustainable cities.

Start with reducing sedentary behavior: A stepwise approach to physical activity counseling in clinical practice

Recently, sedentary behavior recommendations have been included in the public health guidelines of multiple countries, pointing to new opportunities for prevention of chronic disease as well as a potential strategy for initiating long-term behavior change.

OBJECTIVE

To propose an evidence-informed approach to physical activity counseling that starts with a focus on reducing sedentary time.

METHODS

We put forward a case for addressing changes in sedentary behavior in clinical practice using a narrative review. We also propose a new approach for the assessment and counselling of patients with respect to movement behaviors.

RESULTS

There is evidence to support a stepwise approach to physical activity counseling that starts with targeting sedentary behavior, particularly in those who are highly sedentary, or those who have chronic disease, or physical impairments.

CONCLUSIONS

Our approach encourages clinicians to consider sedentary behavior counseling as a critical first step to physical activity counseling. For many patients, this initial step of reducing sedentary behavior could build a pathway to an active lifestyle.

PRACTICAL IMPLICATIONS

A shift from long periods of sedentary time to daily routines incorporating more light intensity physical activity could result in meaningful health improvements. Importantly, this approach may be more feasible for highly inactive patients.

Sitting less and moving more for improved metabolic and brain health in type 2 diabetes: 'OPTIMISE your health' trial protocol

Background

Clinical practice guidelines recommend that adults with type 2 diabetes (T2D) sit less and move more throughout the day. The 18-month OPTIMISE Your Health Clinical Trial was developed to support desk-based workers with T2D achieve these recommendations. The two-arm protocol consists of an intervention and control arms. The intervention arm receives 6 months health coaching, a sit-stand desktop workstation and an activity tracker, followed by 6 months of text message support, then 6 months maintenance. The control arm receives a delayed modified intervention after 12 months of usual care. This paper describes the methods of a randomised controlled trial (RCT) evaluating the effectiveness and cost-effectiveness of the intervention, compared to a delayed intervention control.

Methods

This is a two-arm RCT being conducted in Melbourne, Australia. Desk-based workers (≥0.8 full-time equivalent) aged 35–65 years, ambulatory, and with T2D and managed glycaemic control (6.5–10.0% HbA1c), are randomised to the multicomponent intervention (target n = 125) or delayed-intervention control (target n = 125) conditions. All intervention participants receive 6 months of tailored health coaching assisting them to “sit less” and “move more” at work and throughout the day, supported by a sit-stand desktop workstation and an activity tracker (Fitbit). Participants receive text message-based extended care for a further 6-months (6–12 months) followed by 6-months of non-contact (12–18 months: maintenance). Delayed intervention occurs at 12–18 months for the control arm. Assessments are undertaken at baseline, 3, 6, 12, 15 and 18-months. Primary outcomes are activPAL-measured sitting time (h/16 h day), glycosylated haemoglobin (HbA1c; %, mmol/mol) and, cognitive function measures (visual learning and new memory; Paired Associates Learning Total Errors [adjusted]). Secondary, exploratory, and process outcomes will also be collected throughout the trial.

Discussion

The OPTIMISE Your Health trial will provide unique insights into the benefits of an intervention aimed at sitting less and moving more in desk-bound office workers with T2D, with outcomes relevant to glycaemic control, and to cardiometabolic and brain health. Findings will contribute new insights to add to the evidence base on initiating and maintaining behaviour change with clinical populations and inform practice in diabetes management.

Trial registration

ANZCTRN12618001159246.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12889-022-13123-x.

Associations of park features with park use and park-based physical activity in an urban environment in Asia: A cross-sectional study

Park use is associated with health, yet our understanding of park features related to their use is limited. Singapore's parks were audited for 30 micro-features, then geospatial analysis characterized micro-features scores for parks nearest to participants' homes. Adults (3,435) reported their park use and park-based physical activity. Using linear regression models, we found living near a park with higher micro-features scores was associated with more time in parks and park-based physical activity. Specific micro-features were associated with more park time (wildlife areas, water features, forested areas, unpaved trails (2-2.6 h/month, p < 0.05)) and with physical activity in parks (water features, forested areas, large playground, open green spaces (1.8-2.2 h/month, p < 0.05)). These findings could inform parks planning to support population-health.

Television viewing time and all-cause mortality: interactions with BMI, physical activity, smoking, and dietary factors

Background

Higher levels of time spent sitting (sedentary behavior) contribute to adverse health outcomes, including earlier death. This effect may be modified by other lifestyle factors. We examined the association of television viewing (TV), a common leisure-time sedentary behavior, with all-cause mortality, and whether this is modified by body mass index (BMI), physical activity, smoking, alcohol intake, soft drink consumption, or diet-associated inflammation.

Methods

Using data from participants in the Melbourne Collaborative Cohort Study, flexible parametric survival models assessed the time-dependent association of self-reported TV time (three categories: < 2 h/day, 2–3 h/day, > 3 h/day) with all-cause mortality. Interaction terms were fitted to test whether there was effect modification of TV time by the other risk factors.

Results

From 19,570 participants, 4,417 deaths were reported over a median follow up of 14.5 years. More TV time was associated with earlier mortality; however, this relationship diminished with increasing age. The hazard ratio (HR) and 95% confidence interval (95% CI) for > 3 h/day compared with < 2 h/day of TV time was 1.34 (1.16, 1.55) at 70 years, 1.14 (1.04, 1.23) at 80 years, and 0.95 (0.84, 1.06) at 90 years. The TV time/mortality relationship was more evident in participants who were physically inactive (compared with active; p for interaction < 0.01) or had a higher dietary inflammatory index score (compared with a lower score; p for interaction = 0.03). No interactions were detected between TV time and BMI, smoking, alcohol intake, nor soft-drink consumption (all p for interaction > 0.16).

Conclusions

The relationship between TV time and all-cause mortality may change with age. It may also be more pronounced in those who are otherwise inactive or who have a pro-inflammatory diet.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12966-022-01273-5.

Impact on adolescent mental health of replacing screen-use with exercise: A prospective cohort study

BACKGROUND

Screen-based device use could increase the risk of adolescent depression. Distinct modalities of screen-use may have differential effects on mental health. We used compositional data analysis to examine how theoretically replacing different screen-uses with exercise might influence future adolescent emotional distress.

METHODS

In 4,599 adolescents (55% female) from a nationally-representative, prospective cohort, we used time-use diary data at age 14 to estimate daily screen use (television, social media, video game, general computer use) and exercise (team sport and individual exercise). The outcome was emotional distress at age 17, assessed using the emotional symptoms subscale of the Strengths and Difficulties Questionnaire.

RESULTS

Theoretically replacing 60 min of total screen time with exercise at age 14 was associated with a 0.05 (95%CI -0.08, -0.02) score reduction on the emotional symptoms' subscale at 17 in fully-adjusted models. Replacing 60 min of television or social media use with team sports was associated with a reduction of 0.17 (95%CI, -0.31, -0.04) and 0.15 (95%CI, -0.29, -0.01) in emotional symptom scores, respectively. We found no change in emotional symptom scores when replacing video game or general computer use with team sport, or when replacing any screen time with individual exercise.

LIMITATIONS

No direct measure of depressive symptoms at follow-up.

CONCLUSIONS

Replacing any screen time with exercise could reduce emotional distress, but the largest effect sizes were associated with replacing time in television watching and social media with team sports. Recommendations to limit screen-use in adolescents may require a nuanced approach for protecting mental health.

Trends in television viewing and overweight /obesity among Nepalese women: Findings from 2006, 2011 and 2016 Nepal Demographic and Health Surveys

BACKGROUND AND AIMS

Associations between overweight/obesity and television (TV) viewing have been identified in high-income countries, but little evidence is available from low- and middle-income countries. This study examined the trends and correlates of television viewing and overweight/obesity among Nepalese women between 2006 and 2016.

METHODS AND RESULTS

We analysed the data from 22,161 women aged 15-49 years who took part in Nepal Demographic Health Surveys 2006 (n = 10,115), 2011 (n = 5,881) or 2016 (n = 6,165). Trained staff collected data on TV viewing and sociodemographic attributes from a face-to-face survey while height and weight were measured objectively to determine body mass index. Around 38% of the study participants watched TV at least once a week in 2006, which increased to 49% in 2011 and 46% in 2016. The prevalence of overweight and obesity increased from 8% in 2006 to 14.6% in 2011 and 19.8% in 2016. Compared to those who did not watch TV at all, those watching it at least once a week were at 1.54 (95% CI: 1.02-2.33), 1.79 (95% CI: 1.23-2.60) and 1.46 (95% CI: 1.13-1.88) times higher odds of being overweight/obese in 2006, 2011 and 2016 respectively.

CONCLUSION

The prevalence of TV viewing rose among women in Nepal between 2006 and 2016 and was associated with overweight/obesity, which also increased dramatically over this period. Future studies examining the use of multiple screen devices, daily usage duration and content viewed are recommended to understand better the health impacts of transitions to more sedentary living in Nepal and similar settings.

Workplace neighbourhood built-environment attributes and sitting at work and for transport among Japanese desk-based workers

Workplace settings—both internal and external—can influence how workers are physically active or sedentary. Although research has identified some indoor environmental attributes associated with sitting at work, few studies have examined associations of workplace neighbourhood built-environment attributes with workplace sitting time. We examined the cross-sectional associations of perceived and objective workplace neighbourhood built-environment attributes with sitting time at work and for transport among desk-based workers in Japan. Data were collected from a nationwide online survey. The Abbreviated Neighborhood Environment Walkability Scale (n = 2137) and Walk Score® (for a subsample of participants; n = 1163) were used to assess perceived and objective built-environment attributes of workplace neighbourhoods. Self-reported daily average sitting time at work, in cars and in public transport was measured using a Japanese validated questionnaire. Linear regression models estimated the associations of workplace neighbourhood built-environment attributes with sitting time. All perceived workplace neighbourhood built-environment attributes were positively correlated with Walk Score®. However, statistically significant associations with Walk Score® were found for sitting for transport but not for sitting at work. Workers who perceived their workplace neighbourhoods to be more walkable reported a longer time sitting at work and in public transport but a shorter sitting time in cars. Our findings suggest that walkable workplace neighbourhoods may discourage longer car use but have workplaces where workers spend a long time sitting at work. The latter finding further suggests that there may be missed opportunities for desk-based workers to reduce sitting time. Future workplace interventions to reduce sitting time may be developed, taking advantage of the opportunities to take time away from work in workplace neighbourhoods.

Associations of COVID-19 lockdown restrictions with longer-term activity levels of working adults with type 2 diabetes (Preprint)

Background

Lockdown restrictions reduce COVID-19 community transmission; however, they may pose challenges for noncommunicable disease management. A 112-day hard lockdown in Victoria, Australia (commencing March 23, 2020) coincided with an intervention trial of reducing and breaking up sitting time in desk workers with type 2 diabetes who were using a provided consumer-grade activity tracker (Fitbit).

Objective

This study aims to compare continuously recorded activity levels preceding and during COVID-19 lockdown restrictions among working adults with type 2 diabetes participating in a sitting less and moving more intervention.

Methods

A total of 11 participants (n=8 male; mean age 52.8, SD 5 years) in Melbourne, Australia had Fitbit activity tracked before (mean 122.7, SD 47.9 days) and during (mean 99.7, SD 62.5 days) citywide COVID-19 lockdown restrictions. Regression models compared device (Fitbit Inspire HR)–derived activity (steps; metabolic equivalent tasks [METs]; mean time in sedentary, lightly, fairly, and very active minutes; and usual bout durations) during restrictions to prerestrictions. Changes in activity were statistically significant when estimates (Δ%) did not intercept zero.

Results

Overall, there was a decrease in mean steps (–1584 steps/day; Δ% –9%, 95% CI –11% to –7%); METs (–83 METs/day; Δ% –5%, 95% CI –6% to –5%); and lightly active (Δ% –4%, 95% CI –8% to –1%), fairly active (Δ% –8%, 95% CI –21% to –15%), and very active (Δ% –8%, 95% CI –11% to –5%) intensity minutes per day, and increases in mean sedentary minutes per day (51 mins/day; Δ% 3%, 95% CI 1%-6%). Only very active (+5.1 mins) and sedentary (+4.3 mins) bout durations changed significantly.

Conclusions

In a convenience sample of adults with type 2 diabetes, COVID-19 lockdown restrictions were associated with decreases in overall activity levels and increases in very active and sedentary bout durations. A Fitbit monitor provided meaningful continuous long-term data in this context.

Trial Registration

Australian New Zealand Clinical Trials Registry ACTRN12618001159246; https://anzctr.org.au/Trial/Registration/TrialReview.aspx?ACTRN=12618001159246

How supportive are workplace environments for sitting less and moving more? A descriptive study of Australian workplaces participating in the BeUpstanding program

•

Workplaces varied in the number of activity-supportive characteristics present.

•

Spatial characteristics were more common than resource or policy characteristics.

•

Characteristics absent in most workplaces were likely to be modifiable or low cost (“easy wins”).

•

Almost all workplaces had some room for improvement in terms of activity-supportive factors.

Desk-based workers are highly sedentary; this has been identified as an emerging work health and safety issue. To reduce workplace sitting time and promote physical activity it is important to understand what factors are already present within workplaces to inform future interventions. This cross-sectional study examined the prevalence of supportive environmental factors, prior to workplaces taking part in a ‘sit less, move more’ initiative (BeUpstanding). Participants were 291 Australian-based workplace champions (representing 230 organisations) who unlocked the BeUpstanding program’s online toolkit between September 2017 and mid-November 2020, and who completed surveys relating to champion characteristics, organisation and workplace characteristics, and the availability of environmental factors to support sitting less and moving more. Factors were characterized using descriptive statistics and compared across key sectors and factor categories (spatial; resources/initiatives; policy/cultural) using mixed logistic regression models. Of the 42 factors measured, only 11 were present in > 50% of workplaces. Spatial design factors were more likely to be present than resources/initiatives or policy/cultural factors. Centralised printers were the most commonly reported attribute (94%), while prompts to encourage stair use were the least common (4%). Most workplace factors with < 50% prevalence were modifiable and/or were considered modifiable with low cost. Organisations that were public sector, not small/medium, not regional/remote, and not blue-collar had higher odds of having supportive factors than their counterparts; however, workplaces varied considerably in the number of factors present. These findings can assist with developing and targeting initiatives and promoting feasible strategies for desk-based workers to sit less and move more.

Active Aging and Public Health: Evidence, Implications, and Opportunities

By 2050, 20% of the world's population will be over the age of 65 years, with projections that 80% of older adults will be living in low- to middle-income countries. Physical inactivity and sedentary time are particularly high in older adults, presenting unique public health challenges. In this article, we first review evidence that points to multiple beneficial outcomes of active aging, including better physical function, cognitive function, mental health, social health, and sleep and suggest the need to shift the research focus from chronic disease outcomes to more relevant outcomes that affect independence and quality of life. Second, we review the critical role of age-friendly environments in facilitating active aging equitably across different countries and cultures. Finally, we consider emerging opportunities related to social engagement and technology-enabled mobility that can facilitate active aging. In all these contexts, it is a priority to understand and address diversity within the global aging population. Expected final online publication date for the Annual Review of Public Health, Volume 43 is April 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

Musculoskeletal pain and sedentary behaviour in occupational and non-occupational settings: a systematic review with meta-analysis

BACKGROUND

Sedentary behaviour (SB; time spent sitting) is associated with musculoskeletal pain (MSP) conditions; however, no prior systematic review has examined these associations according to SB domains. We synthesised evidence on occupational and non-occupational SB and MSP conditions.

METHODS

Guided by a PRISMA protocol, eight databases (MEDLINE, CINAHL, PsycINFO, Web of Science, Scopus, Cochrane Library, SPORTDiscus, and AMED) and three grey literature sources (Google Scholar, WorldChat, and Trove) were searched (January 1, 2000, to March 17, 2021) for original quantitative studies of adults ≥ 18 years. Clinical-condition studies were excluded. Studies' risk of bias was assessed using the QualSyst checklist. For meta-analyses, random effect inverse-variance pooled effect size was estimated; otherwise, best-evidence synthesis was used for narrative review.

RESULTS

Of 178 potentially-eligible studies, 79 were included [24 general population; 55 occupational (incuding15 experimental/intervention)]; 56 studies were of high quality, with scores > 0.75. Data for 26 were meta-synthesised. For cross-sectional studies of non-occupational SB, meta-analysis showed full-day SB to be associated with low back pain [LBP - OR = 1.19(1.03 - 1.38)]. Narrative synthesis found full-day SB associations with knee pain, arthritis, and general MSP, but the evidence was insufficient on associations with neck/shoulder pain, hip pain, and upper extremities pain. Evidence of prospective associations of full-day SB with MSP conditions was insufficient. Also, there was insufficient evidence on both cross-sectional and prospective associations between leisure-time SB and MSP conditions. For occupational SB, cross-sectional studies meta-analysed indicated associations of self-reported workplace sitting with LBP [OR = 1.47(1.12 - 1.92)] and neck/shoulder pain [OR = 1.73(1.46 - 2.03)], but not with extremities pain [OR = 1.17(0.65 - 2.11)]. Best-evidence synthesis identified inconsistent findings on cross-sectional association and a probable negative prospective association of device-measured workplace sitting with LBP-intensity in tradespeople. There was cross-sectional evidence on the association of computer time with neck/shoulder pain, but insufficient evidence for LBP and general MSP. Experimental/intervention evidence indicated reduced LBP, neck/shoulder pain, and general MSP with reducing workplace sitting.

CONCLUSIONS

We found cross-sectional associations of occupational and non-occupational SB with MSP conditions, with occupational SB associations being occupation dependent, however, reverse causality bias cannot be ruled out. While prospective evidence was inconclusive, reducing workplace sitting was associated with reduced MSP conditions. Future studies should emphasise prospective analyses and examining potential interactions with chronic diseases.

PROTOCOL REGISTRATION

PROSPERO ID # CRD42020166412 (Amended to limit the scope).

Contrasting compositions of sitting, standing, stepping, and sleeping time: associations with glycaemic outcome by diabetes risk

BACKGROUND

Recent evidence suggests that prolonged sitting and its adverse impact on glycaemic indicators appear to be proportional to the degree of insulin resistance. To investigate this finding in a free-living context, we aimed to examine associations of device-measured 24-h time-use compositions of sitting, standing, stepping, and sleeping with fasting glucose (FPG) and 2 h post-load glucose (2hPLG) levels, and to examine separately the associations with time-use compositions among those at lower and at higher risk of developing type 2 diabetes.

METHODS

Cross-sectional analyses examined thigh-worn inclinometer data (activPAL, 7 day, 24 h/day protocol) from 648 participants (aged 36-80 years) at either lower (< 39 mmol/mol; < 5.7% HbA1c) or higher (≥39 mmol/mol; ≥5.7% HbA1c) diabetes risk from the 2011-2012 Australian Diabetes, Obesity and Lifestyle study. Multiple linear regression models were used to examine associations of differing compositions with FPG and 2hPLG, with time spent in each behaviour allowed to vary up to 60 min.

RESULTS

In general, the associations with the FPG within the time-use compositions were small, with statistically significant associations observed for sitting and sleeping (in the lower diabetes risk group) and standing (in higher diabetes risk group) only. For 2hPLG, statistically significant associations were observed for stepping only, with findings similar between lower (β = - 0.12 95%CI:-0.22, - 0.02) and higher (β = - 0.13 95%CI:-0.26, - 0.01) risk groups. Varying the composition had minimal impact on FPG; however 1 h less sitting time and equivalent increase in standing time was associated with attenuated FPG levels in higher risk only (Δ FPG% = - 1.5 95%CI: - 2.4, - 0.5). Large differences in 2hPLG were observed for both groups when varying the composition. One hour less sitting with equivalent increase in stepping was associated with attenuated 2hPLG, with estimations similar in lower (Δ 2hPLG% = - 3.8 95%CI: - 7.3, - 0.2) and higher (Δ 2hPLG% = - 5.0 95%CI: - 9.7, - 0.0) risk for diabetes.

CONCLUSIONS

In middle-aged and older adults, glycaemic control could be improved by reducing daily sitting time and replacing it with stepping. Standing could also be beneficial for those at higher risk of developing type 2 diabetes.

Acute cardiometabolic effects of brief active breaks in sitting for patients with rheumatoid arthritis

Exercise is a treatment in rheumatoid arthritis, but participation in moderate-to-vigorous exercise is challenging for some patients. Light-intensity breaks in sitting could be a promising alternative. We compared the acute effects of active breaks in sitting with those of moderate-to-vigorous exercise on cardiometabolic risk markers in patients with rheumatoid arthritis. In a crossover fashion, 15 women with rheumatoid arthritis underwent three 8-h experimental conditions: prolonged sitting (SIT), 30-min bout of moderate-to-vigorous exercise followed by prolonged sitting (EX), and 3-min bouts of light-intensity walking every 30 min of sitting (BR). Postprandial glucose, insulin, c-peptide, triglycerides, cytokines, lipid classes/subclasses (lipidomics), and blood pressure responses were assessed. Muscle biopsies were collected following each session to assess targeted proteins/genes. Glucose [-28% in area under the curve (AUC), P = 0.036], insulin (-28% in AUC, P = 0.016), and c-peptide (-27% in AUC, P = 0.006) postprandial responses were attenuated in BR versus SIT, whereas only c-peptide was lower in EX versus SIT (-20% in AUC, P = 0.002). IL-1β decreased during BR, but increased during EX and SIT (P = 0.027 and P = 0.085, respectively). IL-1ra was increased during EX versus BR (P = 0.002). TNF-α concentrations decreased during BR versus EX (P = 0.022). EX, but not BR, reduced systolic blood pressure (P = 0.013). Lipidomic analysis showed that 7 of 36 lipid classes/subclasses were significantly different between conditions, with greater changes being observed in EX. No differences were observed for protein/gene expression. Brief active breaks in sitting can offset markers of cardiometabolic disturbance, which may be particularly useful for patients who may find it difficult to adhere to exercise.NEW & NOTEWORTHY Exercise is a treatment in rheumatoid arthritis but is challenging for some patients. Light-intensity breaks in sitting could be a promising alternative. Our findings show beneficial, but differential, cardiometabolic effects of active breaks in sitting and exercise in patients with rheumatoid arthritis. Breaks in sitting mainly improved glycemic and inflammatory markers, whereas exercise improved lipidomic and hypotensive responses. Breaks in sitting show promise in offsetting aspects of cardiometabolic disturbance associated with prolonged sitting in rheumatoid arthritis.

Urban Densification and Physical Activity Change: A 12-Year Longitudinal Study of Australian Adults

Urbanization, a major force driving changes in neighborhood environments, may affect residents' health by influencing their daily activity levels. We examined associations of population density changes in urban areas with adults' physical activity changes over 12 years using data from the Australian Diabetes, Obesity and Lifestyle Study (1999-2012). The analytical sample contained 2,354 participants who remained at the same residential address throughout the study period in metropolitan cities and regional cities (42 study areas). Census-based population density measures were calculated for 1-km-radius buffers around their homes. Population density change was estimated using linear growth models. Two-level linear regression models were used to assess associations between changes in population density and changes in self-reported walking and physical activity durations. The average change in population density was 0.8% per year (range, -4.1 to 7.8) relative to baseline density. After adjustment for confounders, each 1% annual increase in population density was associated with 8.5-minutes/week (95% confidence interval: 0.6, 16.4) and 19.0-minutes/week (95% confidence interval: 3.7, 34.4) increases in walking and physical activity, respectively, over the 12-year study period. Increasing population density through urban planning policies of accommodating population growth within the existing urban boundary, rather than expanding city boundaries, could assist in promoting physical activity at the population level.

Sugar sweetened beverages and increasing prevalence of type 2 diabetes in the Indigenous community of Australia

AIMS

The aim of this viewpoint was to discuss a profound health gap in type 2 diabetes that exists between Indigenous and non-Indigenous Australians.

DATA SYNTHESIS

In Australia, type 2 diabetes is ranked as the fastest growing chronic condition, with the rates of type 2 diabetes higher among Indigenous than non-Indigenous Australians. Improvements to diet could aid in reducing overweight and obesity in the Indigenous community, with sugar sweetened beverages (SSBs) examples of discretionary foods that contain a high amount of sugar. The marked increase in type 2 diabetes, obesity and consumption of SSBs in the Indigenous community may suggest that type 2 diabetes may result from weight gain caused by SSB consumption. Recent evidence suggests that higher consumption of SSBs was associated with greater incidence of type 2 diabetes independent of adiposity. Some determinants influencing increased SSBs consumption in the Indigenous population include advertising, marketing, availability and affordability.

CONCLUSIONS

The prevalence rates of type 2 diabetes continue to be higher among Indigenous than non-Indigenous Australians and overall, a link between SSBs and risk of type 2 diabetes is reported. Three solutions to high SSBs consumption in Indigenous communities include increased availability, affordability, and accessibility of healthy food and drink, engagement of Indigenous people in offering solutions including discussion of a sugar tax on SSBs framed with Indigenous input, and the provision of clean community water supply and water bubblers.

Different frequencies of active interruptions to sitting have distinct effects on 22 h glycemic control in type 2 diabetes

BACKGROUND & AIMS

Whether the frequency of interruptions to sitting time involving simple resistance activities (SRAs), compared to uninterrupted sitting, differentially affected 22 h glycemic control in adults with medication-controlled type 2 diabetes (T2D).

METHODS & RESULTS

Twenty-four participants (13 men; mean ± SD age 62 ± 8 years) completed three 8 h laboratory conditions: SIT: uninterrupted sitting; SRA3: sitting interrupted with 3 min of SRAs every 30 min; and, SRA6: sitting interrupted with 6 min of SRAs every 60 min. Flash glucose monitors assessed glycemic control over a 22 h period. No differences were observed between conditions for overall 22 h glycemic control as measured by AUC_total, mean glucose and time in hyperglycemia. During the 3.5 h post-lunch period, mean glucose was significantly lower during SRA6 (10.1 mmol·L^-1, 95%CI 9.2, 11.0) compared to SIT (11.1 mmol·L^-1, 95%CI 10.2, 12.0; P = 0.006). Post-lunch iAUC_net was significantly lower during SRA6 (6.2 mmol·h·L^-1, 95%CI 3.3, 9.1) compared to SIT (9.9 mmol·h·L^-1, 95%CI 7.0, 12.9; P = 0.003). During the post-lunch period, compared to SIT (2.2 h, 95%CI 1.7, 2.6), time in hyperglycemia was significantly lower during SRA6 (1.5 h, 95%CI 1.0, 1.9, P = 0.001). Nocturnal mean glucose was significantly lower following the SRA3 condition (7.6 mmol·L^-1, 95%CI 7.1, 8.1) compared to SIT (8.1 mmol·L^-1, 95%CI 7.6, 8.7, P = 0.024).

CONCLUSIONS

With standardized total activity time, less-frequent active interruptions to sitting may acutely improve glycemic control; while more-frequent interruptions may be beneficial for nocturnal glucose in those with medication-controlled T2D.

882Relationship of Urban Sprawl with Overweight and Obesity: Roles of Physically-Active and Sedentary Travel Behaviours

Background

Urban sprawl – low-density neighbourhood developments at the city’s periphery – is related to risk of overweight/obesity. Our mediation analysis examined the extent to which this relationship may be explained by physically-active and sedentary travel behaviours.

Methods

We analysed data from 2,465 metropolitan residents in the 2011-12 wave of the Australian Diabetes, Obesity and Lifestyle Study. Urban sprawl measure was geographic information system derived residential proximity to the major city centre. Self-reported weekly frequency of walking for transport (WT) and car driving duration (car use) were used as measures of physically-active and sedentary travel behaviours. Risk of overweight/obesity was calculated using objectively-measured body mass index (&gt; 25 kg/m2). Multi-level regression models and joint-significance mediation tests were used.

Results

Residing near the city centre was associated with higher levels of WT and lower levels of car use. For instance, compared to those living within 10km from the city centre, those living over 30km away had 57% lower WT frequency (p&lt;0.001) and 1.4 hours/week more car use (p=0.002). In turn, lower levels of WT and higher levels car use were associated with elevated overweight/obesity risk.

Conclusions

These analyses suggest that travel behaviors can be potential mediators in relationships of urban sprawl with overweight/obesity. Future studies are warranted to assess causality of these relationships.

Key messages

Urban planning policies need to consider these impacts of the expansion of urban sprawl and promote inner-city high-density development by encouraging more physically-active travel and less time spent sitting in cars to reduce the population burden of overweight/obesity.

513Ophthalmic disease and older adults’ sedentary and physically-active behaviors: Findings from the NEIGE study

Background

Physical inactivity can be associated adversely with markers of eye health, but little is known about how ophthalmic disease (OD) may be related to sedentary behaviour (SB) and different intensities of physical activity in older adults. We compared device-assessed time spent in SB, light-intensity PA (LPA), and moderate-to-vigorous physical activity (MVPA) between older adults with and without OD.

Methods

A randomly-recruited sample of 512 community-dwelling older adults (47% male; aged 65–84 years) in Japan wore a valid tri-axial accelerometer for seven consecutive days in 2017. Prevalence of OD was assessed by medical interview. Times spent in SB, LPA, and MVPA were compared between those with and without OD by compositional multivariate analysis of covariance, adjusting for potential confounders (gender, age, residential area, living arrangement, working, body mass index, self-rated health, and cognitive function).

Results

Overall, percent times spent in SB, LPA, and MVPA during waking hours were 51.0, 44.6, and 4.4, respectively; and, 167 (36.5%) had OD. Activity patterns differed significantly between those with and without OD: in those with OD, the proportion of time spent in MVPA relative to other behaviours was lower, and the proportion of time spent in SB relative to other behaviours was higher.

Conclusions

Older adults with OD were found to be less physically active than those without.

Key messages

While these cross-sectional findings need to be confirmed by evidence from prospective studies, the reciprocal influences of OD and inactivity in older adults should be addressed as scientific, clinical and public health considerations.

The association of TV viewing time with 2-hour plasma glucose is modified by a prudent dietary pattern

BACKGROUND

TV viewing is associated with elevated plasma glucose, but it is not clear whether such associations can be modified by dietary patterns.

METHODS

We examined the interactions of TV viewing time and dietary patterns in relation to fasting and 2-hour plasma glucose. Cross-sectional analyses were performed among participants (N = 3081; 44.7% male; mean age 57.8 years) from the 2011 to 2012 Australian Diabetes, Obesity and Lifestyle Study (AusDiab) without clinically diagnosed diabetes or cardiovascular disease. Factor analysis (principal component) was conducted to identify dietary patterns. Multivariable linear regression models were used to examine distinct associations of TV viewing time and dietary patterns with fasting and 2-hour plasma glucose. Dichotomous TV viewing time (low: ≤ 2 h/d vs high: >2 h/d) and quartiles of dietary patterns were further combined to examine the joint associations with plasma glucose.

RESULTS

Three dietary patterns were identified: prudent, Western, and mixed. TV viewing time was positively associated (β = .01, P < .05) and the prudent dietary pattern was inversely associated (β = -.03, P < .05) with log transformed 2-hour plasma glucose. Compared with participants with high TV viewing/lowest prudent dietary pattern, participants with low TV viewing/highest prudent diet had the lowest 2-hour plasma glucose (β = -.05, P = .028). No interactions were found between TV viewing time and the Western dietary pattern, nor the mixed dietary pattern, in relation to either fasting or 2-hour plasma glucose.

CONCLUSIONS

Following a prudent dietary pattern may attenuate the adverse effect of TV viewing on 2-hour plasma glucose. Prospective studies and intervention trials are needed to further clarify these relationships.

Sedentary behaviour and bone health in older adults: a systematic review

Older adults spend more than 8 h/day in sedentary behaviours. Detrimental effects of sedentary behaviour (SB) on health are established, yet little is known about SB and bone health (bone mineral density; BMD) in older adults. The purpose of this review is to examine associations of SB with BMD in older adults. Five electronic databases were searched: Web of Science (Core Collection); PubMed; EMBASE; Sports Medicine and Education and PsycInfo. Inclusion criteria were healthy older adults mean age ≥ 65 years; measured SB and measured BMD using dual-energy X-ray absorptiometry. Quality was assessed using National Institute of Health Quality Assessment Tool for Observational Cohort and Cross-Sectional Studies. After excluding duplicates 17813 papers were assessed; 17757 were excluded on title/abstract, 49 at full text, resulting in two prospective and five cross-sectional observational studies reviewed. Four were rated 'good' and three were rated 'fair' using the quality assessment criteria. Findings varied across the studies and differed by gender. In women, four studies reported significant positive associations of SB with BMD at different sites, and two found significant negative associations. Five studies which examined both men and women, men reported negative or no associations of SB with femoral neck, pelvic, whole body, spine or leg BMD. Whilst these findings suggest differences between men and women in the associations of SB with BMD, they may be due to the varying anatomical sections examined for BMD, the different methods used to measure SB, the varied quality of the studies included and the limited number of published findings.

Descriptive Epidemiology of Interruptions to Free-Living Sitting Time in Middle-Age and Older Adults

National guidelines recommend physically active interruptions to sitting time, however, the characteristics of these interruptions are broadly stated and ill-defined. A robust methodology for population surveillance for such interruptions is needed.

PURPOSE

To describe the frequency and characteristics (i.e., duration, stepping time, and estimated intensity) of all interruptions and physically active interruptions to adults' free-living sitting time (i.e., transitions from sitting to upright posture) across segments of the population.

METHODS

Australian Diabetes, Obesity and Lifestyle (AusDiab) study participants (321 men; 406 women; mean ± SD 58.0 ± 10.3 years) wore the activPAL3TM for ≥1 valid day. The characteristics of interruptions from laboratory studies demonstrating health benefits were selected to define active interruptions (≥5 min upright and/or ≥ 2 min stepping) and ambulatory interruptions (≥2 min stepping). The frequency and characteristics of all, active, and ambulatory interruptions were described and compared by age, gender, diabetes status, and body mass index.

RESULTS

Adults averaged 55.0 ± 21.8 interruptions per day, but only 20.3 ± 6.7 were active and 14.0 ± 5.4 were ambulatory. Median (25th, 75th percentile) duration was 2.6 (0.9, 7.8) minutes, stepping time was 0.8 (0.3, 2.0) minutes, and estimated energy expenditure was 4.3 (1.4, 12.5) MET-min. Those who were older, had obesity, or had diabetes had significantly (p < 0.05) fewer interruptions of all types and less stepping time during active interruptions than their counterparts (Cohen's d < 0.2).

CONCLUSION

Free-living interruptions were often less active than interruptions performed in effective acute laboratory studies and their content varied widely between population groups. Monitoring all interruptions as well as those that are more active is advisable to provide a comprehensive understanding of free-living sedentary behavior.

Frequency of Interruptions to Sitting Time: Benefits for Postprandial Metabolism in Type 2 Diabetes

OBJECTIVE

To determine whether interrupting sitting with brief bouts of simple resistance activities (SRAs) at different frequencies improves postprandial glucose, insulin, and triglycerides in adults with medication-controlled type 2 diabetes (T2D).

RESEARCH DESIGN AND METHODS

Participants (n = 23, 10 of whom were female, with mean ± SD age 62 ± 8 years and BMI 32.7 ± 3.5 kg · m^-2) completed a three-armed randomized crossover trial (6- to 14-day washout): sitting uninterrupted for 7 h (SIT), sitting with 3-min SRAs (half squats, calf raises, gluteal contractions, and knee raises) every 30 min (SRA3), and sitting with 6-min SRAs every 60 min (SRA6). Net incremental areas under the curve (iAUC_net) for glucose, insulin, and triglycerides were compared between conditions.

RESULTS

Glucose and insulin 7-h iAUC_net were attenuated significantly during SRA6 (glucose 17.0 mmol · h · L^-1, 95% CI 12.5, 21.4; insulin 1,229 pmol · h · L^-1, 95% CI 982, 1,538) in comparison with SIT (glucose 21.4 mmol · h · L^-1, 95% CI 16.9, 25.8; insulin 1,411 pmol · h · L^-1, 95% CI 1,128, 1,767; P < 0.05) and in comparison with SRA3 (for glucose only) (22.1 mmol · h · L^-1, 95% CI 17.7, 26.6; P = 0.01) No significant differences in glucose or insulin iAUC_net were observed in comparison of SRA3 and SIT. There was no statistically significant effect of condition on triglyceride iAUC_net.

CONCLUSIONS

In adults with medication-controlled T2D, interrupting prolonged sitting with 6-min SRAs every 60 min reduced postprandial glucose and insulin responses. Other frequencies of interruptions and potential longer-term benefits require examination to clarify clinical relevance.