Associations between objectively assessed and self-reported sedentary time with mental health in adults: an analysis of data from the Health Survey for England

The Effects of Lower Extremity Strengthening Delivered in the Workplace on Physical Function and Work-Related Outcomes Among Desk-Based Workers: A Randomized Controlled Trial

OBJECTIVE

The aim of this study was to assess the effectiveness of a workplace leg-strengthening program on self-reported function, physical capacity, and work-related outcomes among desk-based workers.

METHODS

Forty-three desk-based workers were randomized to a 12-week exercise program or no exercise control. The primary outcome was change in self-reported physical function on the Lower Extremity Functional Scale (LEFS) from baseline to follow-up. Secondary outcomes were physical capacity (mobility, strength), self-reported outcomes (pain, depressive symptoms), and work-related outcomes (resilience, work ability).

RESULTS

The exercise group showed greater improvements in LEFS and mobility. No significant between-group differences existed in knee strength or remaining self-reported and work-related outcomes.

CONCLUSION

Workplace implemented leg-strengthening exercises are effective at improving self-reported and physical health outcomes of desk-based workers. Moving forward, occupational exercise interventions may be essential to enhance worker longevity among the aging, sedentary workforce.

A Practical Guide to Analyzing Time-Varying Associations between Physical Activity and Affect Using Multilevel Modeling

There is growing interest in within-person associations of objectively measured physical and physiological variables with psychological states in daily life. Here we provide a practical guide with SAS code of multilevel modeling for analyzing physical activity data obtained by accelerometer and self-report data from intensive and repeated measures using ecological momentary assessments (EMA). We review previous applications of EMA in research and clinical settings and the analytical tools that are useful for EMA research. We exemplify the analyses of EMA data with cases on physical activity data and affect and discuss the future challenges in the field.

Is objectively measured light-intensity physical activity associated with health outcomes after adjustment for moderate-to-vigorous physical activity in adults? A systematic review

Background

An increasing number of studies have demonstrated that light-intensity physical activity (LPA) confers health benefits after adjustment for moderate-to-vigorous physical activity (MVPA). The purpose of this systematic review was to summarize existing epidemiological evidence on associations of objectively measured LPA with health outcomes in adults.

Methods

This review was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. We searched on PubMed, Web of Science, CINAL, and Cochrane Library for articles analyzing the association between objectively determined LPA and health outcomes that were published up to January 2017. Data were extracted regarding authors, publication year, country of survey, study setting, number of participants, study design, physical activity (PA) assessment (type of accelerometer and intensity), health outcomes, confounders, and results (summary measures and association). A coding system was used to summarize the results.

Results

Of the 3254 studies identified, 24 cross-sectional and 6 longitudinal studies were included in this review. Most of the studies targeted the Western population. LPA was inversely associated with all-cause mortality risk and associated favorably with some cardiometabolic risk factors including waist circumference, triglyceride levels, insulin, and presence of metabolic syndrome. Only a small amount of data were available on mental health and cognitive function.

Conclusions

LPA appears to be beneficially associated with important health outcomes after adjustment for MVPA in the adult population. Although current global PA guidelines recommend only MVPA, promoting LPA may confer additional health benefits.

Electronic supplementary material

The online version of this article (10.1186/s12966-018-0695-z) contains supplementary material, which is available to authorized users.

Changes in non-occupational sedentary behaviours across the retirement transition: the Finnish Retirement and Aging (FIREA) study

Background

Retirement is a major life transition which may influence health behaviours and time use. Little is known about how sedentary behaviour changes as a result of increased time availability after retirement. The aim of this study was to examine changes in non-occupational sedentary behaviours across the retirement transition. In addition, we examined which preretirement characteristics were associated with these changes.

Methods

The study population consisted of 2011 participants from the Finnish Retirement and Aging Study. Repeated postal survey including questions on sedentary behaviour domains (television viewing, computer use at home, sitting in a vehicle and other sitting) were conducted once a year across the retirement transition, covering on average 3.4 study waves. Linear regression with generalised estimating equations was used for the analyses.

Results

Total sedentary time increased by 73 (95% CI 66 to 80) min/day during the retirement transition. Of the domain-specific sedentary behaviours, television viewing time increased by 28 (95% CI 25 to 32) min/day, computer use at home by 19 (95% CI 17 to 22) min/day and other sitting time by 37 (95% CI 33 to 41) min/day, while time sitting in a vehicle decreased by 6 (95% CI 4 to 9) min/day. Highest increase in total sedentary time was among women and persons who had high occupational sitting time, low physical activity level, sleep difficulties, mental disorders or poor health before retirement (all p values for interaction <0.03).

Conclusion

Total and domain-specific sedentary time, except sitting in a vehicle, increased during the retirement transition.

Self-reported domain-specific and accelerometer-based physical activity and sedentary behaviour in relation to psychological distress among an urban Asian population

Background

The interpretation of previous studies on the association of physical activity and sedentary behaviour with psychological health is limited by the use of mostly self-reported physical activity and sedentary behaviour, and a focus on Western populations. We aimed to explore the association of self-reported and devise-based measures of physical activity and sedentary behaviour domains on psychological distress in an urban multi-ethnic Asian population.

Methods

From a population-based cross-sectional study of adults aged 18–79 years, data were used from an overall sample (n = 2653) with complete self-reported total physical activity/sedentary behaviour and domain-specific physical activity data, and a subsample (n = 703) with self-reported domain-specific sedentary behaviour and accelerometry data. Physical activity and sedentary behaviour data were collected using the Global Physical Activity Questionnaire (GPAQ), a domain-specific sedentary behaviour questionnaire and accelerometers. The Kessler Screening Scale (K6) and General Health Questionnaire (GHQ-12) were used to assess psychological distress. Logistic regression models were used to calculate odds ratios (ORs) and 95% confidence intervals, adjusted for socio-demographic and lifestyle characteristics.

Results

The sample comprised 45.0% men (median age = 45.0 years). The prevalence of psychological distress based on the K6 and GHQ-12 was 8.4% and 21.7%, respectively. In the adjusted model, higher levels of self-reported moderate-to-vigorous physical activity (MVPA) were associated with significantly higher odds for K6 (OR = 1.47 [1.03–2.10]; p-trend = 0.03) but not GHQ-12 (OR = 0.97 [0.77–1.23]; p-trend = 0.79), when comparing the highest with the lowest tertile. Accelerometry-assessed MVPA was not significantly associated with K6 (p-trend = 0.50) nor GHQ-12 (p-trend = 0.74). The highest tertile of leisure-time physical activity, but not work- or transport-domain activity, was associated with less psychological distress using K6 (OR = 0.65 [0.43–0.97]; p-trend = 0.02) and GHQ-12 (OR = 0.72 [0.55–0.93]; p-trend = 0.01). Self-reported sedentary behaviour was not associated with K6 (p-trend = 0.90) and GHQ-12 (p-trend = 0.33). The highest tertile of accelerometry-assessed sedentary behaviour was associated with significantly higher odds for K6 (OR = 1.93 [1.00–3.75]; p-trend = 0.04), but not GHQ-12 (OR = 1.34 [0.86–2.08]; p-trend = 0.18).

Conclusions

Higher levels of leisure-time physical activity and lower levels of accelerometer-based sedentary behaviour were associated with lower psychological distress. This study underscores the importance of assessing accelerometer-based and domain-specific activity in relation to mental health, instead of solely focusing on total volume of activity.

Electronic supplementary material

The online version of this article (10.1186/s12966-018-0669-1) contains supplementary material, which is available to authorized users.

Correlates of objectively measured sedentary time in adults with intellectual disabilities

Sedentary behaviour is an independent risk factor for adverse health conditions. Adults with intellectual disabilities spend a high proportion of their day engaged in sedentary behaviour, however, there is limited evidence on potential correlates of objectively measured sedentary behaviour in this population group. In Glasgow, UK from July to September 2017, a secondary analysis of pooled baseline accelerometer data from two randomised controlled trials of lifestyle behaviour change programmes was conducted. Backwards linear regression was used to investigate the associations between demographic, biological, and environmental correlates and objective measure of sedentary behaviour (percentage of time spent sedentary). One-hundred and forty-three participants provided valid accelerometer data. Mean percentage time spent sedentary (adjusted for wear time) was 72.9% [Standard Deviation (SD) = 8.7] per day. In the final model, physical and mental health problems were significantly (p < 0.05) associated with increased percentage time spent sedentary. This is the first study to provide evidence on multi-level, demographic, biological, and environmental correlates of objectively measured sedentary behaviour in adults with intellectual disabilities. To inform the development of interventions to modify sedentary behaviours in adults with intellectual disabilities, further research is required including a wide range of socio-ecological correlates.

Prospective relationship between objectively measured light physical activity and depressive symptoms in later life

BACKGROUND

The use of self-report measures of physical activity is a serious methodological weakness in many studies of physical activity and depressive symptoms. It is still equivocal whether light physical activity protects older adults from depressive symptoms.

OBJECTIVE

This study aimed to explore whether objectively measured light physical activity, independent of sedentary and moderate-to-vigorous activity, is associated with a reduced risk of subsequent depressive symptoms in older adults.

METHODS

This was a 2-year prospective cohort study. A total of 285 community-dwelling older adults aged 65 years or older were interviewed in 2012. A second wave of assessment was carried out in 2014 involving 274 (96.1%) participants. Time spent in physical activity at different intensities was assessed using triaxial accelerometers. Depressive symptoms were measured using the 15-item Geriatric Depression Scale. Negative binomial regression models with adjustment for baseline depressive symptoms, accelerometer wear time, socio-demographic variables, lifestyle behaviors, and chronic disease conditions were conducted.

RESULTS

Time spent in moderate-to-vigorous and light physical activities were both inversely related to depressive symptoms at follow-up. Sedentary time was associated with an increased risk of subsequent depressive symptoms. When sedentary or moderate-to-vigorous activity were included in the multivariable-adjusted regression models with light physical activity simultaneously, only light physical activity remained significant. Sensitivity analyses for assessing confounding and reverse causation provided further support for the stability of these findings.

CONCLUSION

Light physical activity, independent of sedentary and moderate-to-vigorous activity, is associated with a reduced risk of subsequent depressive symptoms in later life. Copyright © 2017 John Wiley & Sons, Ltd.

Objectively Measured Daily Physical Activity and Postural Changes as Related to Positive and Negative Affect Using Ambulatory Monitoring Assessments

OBJECTIVE

The aim of the study was to determine whether objectively measured daily physical activity and posture of sitting, standing, and sit-to-stand transitions are associated with daily assessments of affect.

METHODS

Participants (N = 51, 49% female) wore ActivPal accelerometers for 24 h/d for seven consecutive days. Time spent sitting, standing, and being physically active and sit-to-stand transitions were derived for each day. Participants also completed a mood inventory each evening. Multilevel models examined within- and between-person associations of daily physical activity with positive and negative affect, adjusting for age, sex, body mass index, education, and sleep duration.

RESULTS

Within-person associations showed that a 1-hour increase in daily physical activity was associated with a decrease in negative affect over the same day (B = -0.11, 95% confidence interval [CI], -0.21 to -0.01). Between-person associations indicated a borderline significant association between higher average daily physical activity levels and higher positive affect (B = 1.85, 95% CI = -0.25 to 3.94). There were no between- or within-person associations between sitting, standing, and sit-to-stand transitions with affect.

CONCLUSIONS

Promoting physical activity may be a potential intervention strategy to acutely suppress negative affective states.

Mobile Phone Detection of Semantic Location and Its Relationship to Depression and Anxiety

BACKGROUND

Is someone at home, at their friend's place, at a restaurant, or enjoying the outdoors? Knowing the semantic location of an individual matters for delivering medical interventions, recommendations, and other context-aware services. This knowledge is particularly useful in mental health care for monitoring relevant behavioral indicators to improve treatment delivery. Local search-and-discovery services such as Foursquare can be used to detect semantic locations based on the global positioning system (GPS) coordinates, but GPS alone is often inaccurate. Mobile phones can also sense other signals (such as movement, light, and sound), and the use of these signals promises to lead to a better estimation of an individual's semantic location.

OBJECTIVE

We aimed to examine the ability of mobile phone sensors to estimate semantic locations, and to evaluate the relationship between semantic location visit patterns and depression and anxiety.

METHODS

A total of 208 participants across the United States were asked to log the type of locations they visited daily, using their mobile phones for a period of 6 weeks, while their phone sensor data was recorded. Using the sensor data and Foursquare queries based on GPS coordinates, we trained models to predict these logged locations, and evaluated their prediction accuracy on participants that models had not seen during training. We also evaluated the relationship between the amount of time spent in each semantic location and depression and anxiety assessed at baseline, in the middle, and at the end of the study.

RESULTS

While Foursquare queries detected true semantic locations with an average area under the curve (AUC) of 0.62, using phone sensor data alone increased the AUC to 0.84. When we used Foursquare and sensor data together, the AUC further increased to 0.88. We found some significant relationships between the time spent in certain locations and depression and anxiety, although these relationships were not consistent.

CONCLUSIONS

The accuracy of location services such as Foursquare can significantly benefit from using phone sensor data. However, our results suggest that the nature of the places people visit explains only a small part of the variation in their anxiety and depression symptoms.

Impact of a workplace 'sit less, move more' program on efficiency-related outcomes of office employees

Background

Few studies have examined the impact of ‘sit less, move more’ interventions on workplace performance. This study assessed the short and mid-term impacts of and patterns of change within, a 19-week workplace web-based intervention (Walk@WorkSpain; W@WS; 2010–11) on employees´ presenteeism, mental well-being and lost work performance.

Methods

A site randomised control trial recruited employees at six Spanish university campuses (n = 264; 42 ± 10 years; 171 female), assigned by worksite and campus to an Intervention (IG; used W@WS; n = 129; 87 female) or an active Comparison group (A-CG; pedometer, paper diary and self-reported sitting time; n = 135; 84 female). A linear mixed model assessed changes between the baseline, ramping (8 weeks), maintenance (11 weeks) and follow-up (two months) phases for the IG versus A-CG on (i) % of lost work productivity (Work Limitations Questionnaire; WLQ); (ii) three scales for presenteeism (WLQ) assessing difficulty meeting scheduling demands (Time), performing cognitive and inter-personal tasks (Mental-Interpersonal) and decrements in meeting the quantity, quality and timeliness of completed work (Output); and (iii) mental well-being (Warwick-Edinburgh Mental Well-being Scale). T-tests assessed differences between groups for changes on the main outcomes. In the IG, a multivariate logistic regression model identified patterns of response according to baseline socio-demographic variables, physical activity and sitting time.

Results

There was a significant 2 (group) × 2 (program time points) interaction for the Time (F [3]=8.69, p = 0.005), Mental-Interpersonal (F [3]=10.01, p = 0.0185), Output scales for presenteeism (F [3]=8.56, p = 0.0357), and for % of lost work performance (F [3]=10.31, p = 0.0161). Presenteeism and lost performance rose significantly in both groups across all study time points; after baseline performance was consistently better in the IG than in the A-CG. Better performance was linked to employees being more active (Time, p = 0.041) and younger (Mental-interpersonal, p = 0.057; Output, p = 0.017). Higher total sitting time during nonworking days (Mental-interpersonal, p = 0.019) and lower sitting time during workdays (WLQ Index, p = 0.013) also improved performance.

Conclusion

Versus an active comparison condition, a ‘sit less, move more` workplace intervention effectively reduced an array of markers of lost workday productivity.

Trial registration

NCT02960750; Date of registration: 07/11/2016.

Associations of moderate-to-vigorous-intensity physical activity and body mass index with glycated haemoglobin within the general population: a cross-sectional analysis of the 2008 Health Survey for England

OBJECTIVES

To investigate the associations of objectively measured moderate-to-vigorous-intensity physical activity (MVPA) and body mass index (BMI) with glycated haemoglobin (HbA1c) in a national sample of English adults.

METHODS

The 2008 Health Survey for England data were used with 1109 participants aged ≥18 providing complete data. MVPA time was assessed using an accelerometer. Weighted linear regression models, adjusted for several confounders, quantified the associations between continuous measures of MVPA and BMI with HbA1c. Interaction analyses were implemented to observe whether the association of MVPA with HbA1c was modified by BMI or vice versa. Further weighted linear regression models examined the differences in HbA1c across four mutually exclusive categories of MVPA and BMI: (1) 'physically active and non-obese', (2) 'physically active and obese', (3) 'physically inactive and non-obese' and (4) 'physically inactive and obese'. 'Physically active' was defined as: ≥150 min/week of MVPA. 'Obese' was defined as: BMI ≥30.0 kg/m². A wide range of sensitivity analyses were also implemented.

RESULTS

Every 30 min/day increment in MVPA was associated with a 0.7 mmol/mol (0.07% (p<0.001)) lower HbA1c level. Each 1 kg/m² increment in BMI was associated with a 0.2 mmol/mol (0.02% (p<0.001)) higher HbA1c level. The association of MVPA with HbA1c was stronger in obese individuals (-1.5 mmol/mol (-0.13% (p<0.001))) than non-obese individuals (-0.7 mmol/mol (-0.06% (p<0.001))); p=0.004 for interaction. The association of BMI with HbA1c remained stable across MVPA categories. Compared with individuals categorised as 'physically inactive and obese', only those categorised as 'physically active and obese' or 'physically active and non-obese' had lower HbA1c levels by 2.1 mmol/mol (0.19% (p=0.005)) and 3.5 mmol/mol (0.32% (p<0.001)), respectively. Sensitivity analyses indicated robustness and stability.

CONCLUSIONS

This study emphasises the importance of physical activity as a determinant of HbA1c, and suggests that the associations may be stronger in obese adults.

Association of physical activity and sedentary behavior with depression and anxiety symptoms during pregnancy in a multiethnic cohort of Asian women

OBJECTIVES

This study aimed to investigate associations of physical activity (PA) and sedentary behavior (SB) with depression and anxiety symptoms during pregnancy among Chinese, Malay, and Indian women.

METHODS

Women answered PA and SB (sitting time and television time) interview questions and self-completed the Edinburgh Postnatal Depression Scale (EPDS) and State-Trait Anxiety Inventory (STAI) questionnaires, at week 26-28 gestation. Sufficient levels of PA (≥600MET-minutes/week) and higher sitting time (≥7 h/day) were determined. Associations of PA and SB with probable antenatal depression (EPDS-score ≥15), higher state anxiety (score ≥42), and higher trait anxiety (score ≥43) were determined by logistic regression analysis.

RESULTS

Among the 1144 pregnant women included in the study, 7.3, 22.5, and 23.6 % had probable antenatal depression, higher state anxiety, and higher trait anxiety symptoms, respectively. In the adjusted models, women with sufficient level of PA were less likely to have probable antenatal depression (OR 0.54, 95 % CI 0.31-0.94, p = 0.030) and higher trait anxiety symptoms (OR 0.68, 95 % CI 0.48-0.94, p = 0.022). PA was not associated with state anxiety symptoms. SB was not associated with any of the investigated outcomes.

CONCLUSIONS

Sufficient PA was associated with a reduced likelihood of probable antenatal depression and trait anxiety symptoms. Further investigation of these findings is warranted to determine cause-effect relationships and identify potential preventive strategies.

Impact of screen time on mental health problems progression in youth: a 1-year follow-up study

OBJECTIVES

We examined the relationships between screen time (ST) and mental health problems and also increment of ST and progression of mental health problems in a college-based sample of Chinese youth.

METHODS

We assessed 2521 Chinese college freshmen from October 2013 to December 2014. At baseline, the mean age of participants was 18.43 years (SD 0.96 years), and 1215 (48.2%) participants reported ST >2 h/day. We estimated multivariable-adjusted ORs by using logistic regression models for the risk of developing mental health problems (anxiety, depression and psychopathological symptoms) and/or progression of these problems, according to baseline ST exposure and changes in exposure at follow-up.

RESULTS

At baseline, when ST >2 h/day was compared with ST ≤2 h/day, the OR was 1.38 (95% CI 1.15 to 1.65) for anxiety, 1.55 (95% CI 1.25 to 1.93) for depression and 1.49 (95% CI 1.22 to 1.83) for psychopathological symptoms. The results remained unchanged for depressive and psychopathological symptoms but not for anxiety, after additional adjustment for sex, age, residential background, body mass index, perceived family economy, sleep quality, smoking, alcohol intake, exercise after school and physical activity. When participants who had increased their ST exposure to >2 h/day were compared with those with no change and ST ≤2 h/day, the OR was 1.78 (95% CI 1.12 to 2.83) for anxiety, 1.92 (95% CI 1.23 to 2.83) for depression and 1.93 (95% CI 1.16 to 3.21) for psychopathological symptoms. These associations also remained after additional adjustment.

CONCLUSIONS

The overall effects are consistent yet small for ST/ST increment on mental health problems and its progression. Given the small effect size of the current results, it remains unclear the degree to which ST is a practically significant risk factor for mental health outcomes. Future studies of high quality are necessary to further examine this association and the direction of causality.

Is a single question of the Global Physical Activity Questionnaire (GPAQ) valid for measuring sedentary behaviour in the Chilean population?

A study was conducted to assess the validity of the Global Physical Activity Questionnaire (GPAQ) for measuring sedentary behaviour (SB) in the Chilean adult population. About 217 adults (93/124 male/female, 43.8 ± 15.75 years) who were randomly selected during National Health Survey 2009-2010 completed the protocol. The participants wore an ActiGraph GT3X (AG) for 7 consecutive days and then completed the GPAQ (single-item question for measuring time spent sitting in a usual day). Validity was examined using Spearman's correlation, mean bias and limits of agreement (LoA), with AG (vertical axis <100 counts · min^-1) as the reference standard for estimates of SB in bouts of 1 (AG1), 5 (AG5) and 10 (AG10) min. Agreement between the GPAQ and AG for classifying data into quartiles and tertiles was assessed with kappa method. The GPAQ showed fair correlation with AG1, AG5 and AG10 (range = 0.23-0.26), with large mean biases (range = -293.9, -76.12 min · day^-1). Agreement between the GPAQ and AG1, AG5 and AG10 was poor for categorising time spent in SB into tertiles and quartiles. The single question from the GPAQ has shown fair validity for measuring SB and poor ability for correctly classifying individuals into tertiles or quartiles of SB in a Chilean population.

Total Worker Health Intervention Increases Activity of Sedentary Workers

INTRODUCTION

Office employees are exposed to hazardous levels of sedentary work. Interventions that integrate health promotion and health protection elements are needed to advance the health of sedentary workers. This study tested an integrated intervention on occupational sedentary/physical activity behaviors, cardiometabolic disease biomarkers, musculoskeletal discomfort, and work productivity.

DESIGN

Two-group, RCT. Data were collected between January and August 2014.

SETTING/PARTICIPANTS

Overweight/obese adults working in sedentary desk jobs were randomized to: (1) a health protection-only group (HPO, n=27); or (2) an integrated health protection/health promotion group (HP/HP, n=27).

INTERVENTION

HPO participants received an ergonomic workstation optimization intervention and three e-mails/week promoting rest breaks and posture variation. HP/HP participants received the HPO intervention plus access to a seated activity permissive workstation.

MAIN OUTCOME MEASURES

Occupational sedentary and physical activity behaviors (primary outcomes), cardiometabolic health outcomes, musculoskeletal discomfort, and work productivity (secondary outcomes) were measured at baseline and post-intervention (16 weeks).

RESULTS

The HP/HP group increased occupational light intensity physical activity over the HPO group and used the activity permissive workstations 50 minutes/work day. Significant associations were observed between activity permissive workstation adherence and improvements in several cardiometabolic biomarkers (weight, total fat mass, resting heart rate, body fat percentage) and work productivity outcomes (concentration at work, days missed because of health problems).

CONCLUSIONS

The HP/HP group increased occupational physical activity and greater activity permissive workstation adherence was associated with improved health and work productivity outcomes. These findings are important for employers interested in advancing the well-being of sedentary office workers.

TRIAL REGISTRATION

This study is registered at www.clinicaltrials.gov NCT02071420.

Reliability and validity of three questionnaires measuring context-specific sedentary behaviour and associated correlates in adolescents, adults and older adults

BACKGROUND

Reliable and valid measures of total sedentary time, context-specific sedentary behaviour (SB) and its potential correlates are useful for the development of future interventions. The purpose was to examine test-retest reliability and criterion validity of three newly developed questionnaires on total sedentary time, context-specific SB and its potential correlates in adolescents, adults and older adults.

METHODS

Reliability and validity was tested in six different samples of Flemish (Belgium) residents. For the reliability study, 20 adolescents, 22 adults and 20 older adults filled out the age-specific SB questionnaire twice. Test-retest reliability was analysed using Kappa coefficients, Intraclass Correlation Coefficients and/or percentage agreement, separately for the three age groups. For the validity study, data were retrieved from 62 adolescents, 33 adults and 33 older adults, with activPAL™ as criterion measure. Spearman correlations and Bland-Altman plots (or non-parametric approach) were used to analyse criterion validity, separately for the three age groups and for weekday, weekend day and average day.

RESULTS

The test-retest reliability for self-reported total sedentary time indicated following values: ICC = 0.37-0.67 in adolescents; ICC = 0.73-0.77 in adults; ICC = 0.68-0.80 in older adults. Item-specific reliability results (e.g. context-specific SB and its potential correlates) showed good-to-excellent reliability in 67.94%, 68.90% and 66.38% of the items in adolescents, adults and older adults respectively. All items belonging to sedentary-related equipment and simultaneous SB showed good reliability. The sections of the questionnaire with lowest reliability were: context-specific SB (adolescents), potential correlates of computer use (adults) and potential correlates of motorized transport (older adults). Spearman correlations between self-reported total sedentary time and the activPAL™ were different for each age group: ρ = 0.02-0.42 (adolescents), ρ = 0.06-0.52 (adults), ρ = 0.38-0.50 (older adults). Participants over-reported total sedentary time (except for weekend day in older adults) compared to the activPAL™, for weekday, weekend day and average day respectively by +57.05%, +46.29%, +53.34% in adolescents; +40.40%, +19.15%, +32.89% in adults; +10.10%, -6.24%, +4.11% in older adults.

CONCLUSIONS

The questionnaires showed acceptable test-retest reliability and criterion validity. However, over-reporting of total SB was noticeable in adolescents and adults. Nevertheless, these questionnaires will be useful in getting context-specific information on SB.

The sedentary office: an expert statement on the growing case for change towards better health and productivity

An international group of experts convened to provide guidance for employers to promote the avoidance of prolonged periods of sedentary work. The set of recommendations was developed from the totality of the current evidence, including long-term epidemiological studies and interventional studies of getting workers to stand and/or move more frequently. The evidence was ranked in quality using the four levels of the American College of Sports Medicine. The derived guidance is as follows: for those occupations which are predominantly desk based, workers should aim to initially progress towards accumulating 2 h/day of standing and light activity (light walking) during working hours, eventually progressing to a total accumulation of 4 h/day (prorated to part-time hours). To achieve this, seated-based work should be regularly broken up with standing-based work, the use of sit-stand desks, or the taking of short active standing breaks. Along with other health promotion goals (improved nutrition, reducing alcohol, smoking and stress), companies should also promote among their staff that prolonged sitting, aggregated from work and in leisure time, may significantly and independently increase the risk of cardiometabolic diseases and premature mortality. It is appreciated that these recommendations should be interpreted in relation to the evidence from which they were derived, largely observational and retrospective studies, or short-term interventional studies showing acute cardiometabolic changes. While longer term intervention studies are required, the level of consistent evidence accumulated to date, and the public health context of rising chronic diseases, suggest initial guidelines are justified. We hope these guidelines stimulate future research, and that greater precision will be possible within future iterations.

Physical activity, screen time and self-rated health and mental health in Canadian adolescents

OBJECTIVE

Physical activity (PA) and screen time (ST) are associated with self-rated health (SRH) in adults; however, SRH has been less studied among youth, and information about self-rated mental health (SRMH) is lacking. This study examined the associations of PA and ST with SRH and SRMH among adolescents.

METHODS

Cross-sectional data from the 2011-2012 Canadian Community Health Survey included 7725 participants aged 12-17years, representing 1,820,560 Canadian adolescents. Associations of self-reported PA and ST to SRH and SRMH were assessed, controlling for age, race/ethnicity, smoking, highest household education and weight status.

RESULTS

Excellent/very good SRH was reported by 78% of active vs. 62% of inactive adolescents, and 77% of those meeting vs. 70% of those exceeding ST guidelines (both p<0.001). Excellent/very good SRMH was reported by 81% of active vs. 76% of inactive adolescents, and 84% of those meeting vs. 78% of those exceeding ST guidelines (both p<0.001). Inactive adolescents had twice higher odds of sub-optimal SRH, and inactive girls had 30% greater odds of sub-optimal SRMH. Adolescents exceeding 2h/day ST had 30% greater odds of sub-optimal SRH, and 30-50% greater odds of sub-optimal SRMH.

CONCLUSION

PA and ST are independently associated with health perceptions among Canadian adolescents. Interventions should consider health perceptions in addition to biomedical outcomes.

Don't worry, be happy: cross-sectional associations between physical activity and happiness in 15 European countries

BACKGROUND

Mental health disorders are major contributors to the global burden of disease and their inverse relationship with physical activity is widely accepted. However, research on the association between physical activity and positive mental health outcomes is limited. Happiness is an example of a positive construct of mental health that may be promoted by physical activity and could increase resilience to emotional perturbations. The aim of this study is to use a large multi-country dataset to assess the association of happiness with physical activity volume and its specificity to intensity and/or activity domain.

METHODS

We analysed Eurobarometer 2002 data from 15 countries (n = 11,637). This comprised one question assessing self-reported happiness on a six point scale (dichotomised: happy/unhappy) and physical activity data collected using the IPAQ-short (i.e. walking, moderate, vigorous) and four domain specific items (i.e. domestic, leisure, transport, vocation). Logistic regression was used to examine the association between happiness and physical activity volume adjusted for sex, age, country, general health, relationship status, employment and education. Analyses of intensity and domain specificity were assessed by logistic regression adjusted for the same covariates and physical activity volume.

RESULTS

When compared to inactive people, there was a positive dose-response association between physical activity volume and happiness (highly active: OR = 1.52 [1.28-1.80]; sufficiently active: OR = 1.29 [1.11-1.49]; insufficiently active: OR = 1.20 [1.03-1.39]). There were small positive associations with happiness for walking (OR = 1.02 [1.00-1.03]) and vigorous-intensity physical activity (OR = 1.03 [1.01-1.05). Moderate-intensity physical activity was not associated with happiness (OR = 1.01 [0.99-1.03]). The strongest domain specific associations with happiness were found for "a lot" of domestic (OR = 1.42 [1.20-1.68]) and "some" vocational (OR = 1.33 [1.08-1.64]) physical activity. Happiness was also associated with "a lot" of leisure physical activity (OR = 1.15 [1.02-1.30]), but there were no significant associations for the transport domain.

CONCLUSIONS

Increasing physical activity volume was associated with higher levels of happiness. Although the influence of physical activity intensity appeared minimal, the association with happiness was domain specific and was strongest for "a lot" of domestic and/or "some" vocational physical activity. Future studies to establish causation are indicated and may prompt changes in how physical activity for improving mental health is promoted.