Understanding occupational sitting: prevalence, correlates and moderating effects in Australian employees

OBJECTIVE

To (1) compare occupational sitting between different socio-demographic, health-related, work-related and psychosocial categories, (2) identity socio-demographic, health-related, work-related and psychosocial correlates of occupational sitting, and (3) examine the moderating effect of work-related factors in the relation between correlates and occupational sitting.

METHODS

Randomly-selected Australian adults completed a web-based survey assessing socio-demographic (country of birth, gender, age, education, income), health-related (general health, weight, physical activity), work-related (employment status, occupational task, occupational classification) and sedentary-specific psychosocial (social norm, social support, self-efficacy, control, advantages, disadvantage, intention) factors, and occupational sitting-time. t-tests, ANOVAs and multiple linear regression analyses were conducted (in 2013) on a sample of employees (n=993).

RESULTS

Respondents sat on average for 3.75 (SD=2.45) h/day during work. Investigated correlates explained 41% of the variance in occupational sitting. More occupational sitting was associated with being male, being younger, higher education and income, part-time and full-time employment, sedentary job tasks, white-collar/professional occupations, higher BMI, and perceiving more advantages of sitting less at work. Employment status and occupational classification moderated the association between control to sit less and occupational sitting. A lack of control to sit less was associated with higher occupational sitting in part-time and full-time workers, but not in casual workers; and in white-collar and professional workers, but not in blue-collar workers.

CONCLUSIONS

Most important contributors to occupational sitting were work-related and socio-demographic correlates. More research is needed to confirm present results.

Physical and social home environment in relation to children's overall and home-based physical activity and sedentary time

BACKGROUND

Given the obesity epidemic, it is critical to understand factors associated with youth physical activity and sedentary behavior at home, where youth spend significant time. We examined relationships between these child behaviors and home environment factors.

METHODS

Data were obtained from 713 children aged 6 to 11 in Washington and California 2007-2009. Multivariate regression analyses controlling for socio-demographics examined associations between parent-reported home environment factors and child's accelerometer-measured moderate-to-vigorous physical activity (MVPA) and sedentary time, overall and at home, and parent-reported child screen time.

RESULTS

Children averaged 47.2% of time at home, which included 43.6% and 46.4% of overall MVPA and sedentary behavior, respectively. Parental support for physical activity and having a basketball hoop were positively associated with MVPA and negatively associated with sedentary behavior. Combined parental support and a basketball hoop was associated with even higher MVPA. Children with fewer bedroom media devices and more fixed play equipment had lower overall sedentary behavior and screen time than either factor alone. Findings were similar regardless of weight status.

CONCLUSIONS

Physical and social home environment variables, especially when combined, were related to more child MVPA and less sedentary behavior. Results support addressing multiple home environment factors in childhood obesity prevention.

Summary of international guidelines for physical activity after pregnancy

Postpartum physical activity can improve mood, maintain cardiorespiratory fitness, improve weight control, promote weight loss, and reduce depression and anxiety. This review summarizes current guidelines for postpartum physical activity worldwide. PubMed (MEDLINE) was searched for country-specific government and clinical guidelines on physical activity after pregnancy through the year 2013. Only the most recent guideline was included in the review. An abstraction form facilitated extraction of key details and helped to summarize results. Six guidelines were identified from 5 countries (Australia, Canada, Norway, United Kingdom, and United States). All guidelines were embedded within pregnancy-related physical activity recommendations. All provided physical activity advice related to breastfeeding and 3 remarked about physical activity after cesarean delivery. Recommended physical activities mentioned in the guidelines included aerobic (3/6), pelvic floor exercise (3/6), strengthening (2/6), stretching (2/6), and walking (2/6). None of the guidelines discussed sedentary behavior. The guidelines that were identified lacked specificity for physical activity. Greater clarity in guidelines would be more useful to both practitioners and the women they serve. Postpartum physical activity guidelines have the potential to assist women to initiate or resume physical activity after childbirth so that they can transition to meeting recommended levels of physical activity. Health care providers have a critical role in encouraging women to be active at this time, and the availability of more explicit guidelines may assist them to routinely include physical activity advice in their postpartum care.

Design and evaluation of theory-informed technology to augment a wellness motivation intervention

Integrating mobile technology into health promotion strategies has the potential to support healthy behaviors. A new theory-informed app was designed to augment an intervention promoting wellness motivation in older adults with fall risk and low levels of physical activity. The app content was evaluated for clarity, homogeneity, and validity of motivational messages; both the app and device were evaluated for acceptability and usability. The initial evaluation included nine adults (mean age, 75); four of whom also assessed the app's sensing abilities in the field. As part of an intervention feasibility study, 14 older adults (mean age, 84) also provided a follow-up evaluation of app usability. Evaluation participants assessed the app as valid, usable, acceptable, and able to sense most reported free-living activities, and provided feedback for improving the app. Design processes illustrate methodologic and interpretive efforts to operationalize motivational content in a theory-informed app promoting change in physical activity behavior.

Association of physical activity in the past year and immediately after in vitro fertilization on pregnancy

OBJECTIVE

To estimate the association of physical activity on in vitro fertilization (IVF).

DESIGN

Prospective cohort study.

SETTING

Academic infertility clinic.

PATIENT(S)

Women (n = 121) undergoing nondonor IVF embryo transfer (fresh or frozen).

INTERVENTION(S)

The women completed a questionnaire on past year physical activity and wore an accelerometer from embryo transfer to serum pregnancy testing.

MAIN OUTCOME MEASURE(S)

Implantation, intrauterine gestation, and live birth.

RESULT(S)

Based on self-reported past year physical activity, the adjusted odds of intrauterine gestation was higher among those that had higher continuous active living (odds ratio [OR] 1.96, 95% confidence interval [CI] 1.09-3.50), sports/exercise (OR 1.48, CI 1.02-2.15), and total activity (OR 1.52, 95%CI 1.15-2.01) indices. After embryo transfer, women did almost no vigorous activity (median 0 min/d) as measured by the accelerometer. More of their time was spent in light activity (median 3.0 h/d) and sedentary behaviors (median 9.3 h/d). Accelerometer-measured physical activity and sedentary behavior after embryo transfer were not associated with any IVF outcome.

CONCLUSION(S)

An active lifestyle in the preceding year favorably impacted the IVF outcome. After embryo transfer, women engaged in mostly light physical activity and sedentary behaviors; therefore, the impact of vigorous physical activity on implantation could not be determined.

Sedentary time in children: influence of accelerometer processing on health relations

PURPOSE

Accelerometry is increasingly being used to assess sedentary time in epidemiological studies, yet the most appropriate means of processing these data remains uncertain. This cross-sectional study examined the influence of selected accelerometer cut points and nonwear criteria on associations of sedentary time with adiposity and clustered metabolic risk.

METHODS

Data were from the European Youth Heart Study, which included assessment of sedentary time by accelerometer. Sixteen sedentary time variables were constructed based on combinations of frequently used cut points (100, 500, 800, and 1100 counts per minute) and nonwear criteria (10-, 20-, 60-, and 100-min consecutive zeros). Adiposity was assessed by sum of four skinfold thickness measures. A clustered metabolic risk score was calculated as the mean of standardized metabolic syndrome components, including blood pressure, insulin resistance, and inverted fasting HDL-cholesterol. Analyses were conducted using multilevel cross-sectional time series regression, adjusted for overall physical activity (accelerometer counts per minute). Meta-analysis was used to obtain pooled estimates of the exposure-outcome association over all processing protocols; meta-regression was used to determine the influence of nonwear and cut point protocol on observed associations.

RESULTS

Sedentary time follows a power law with cut point (exponent = 0.27) and zero string (exponent = 0.03), and it was positively associated with clustered metabolic risk (β = 0.0051; 95% confidence interval = 0.0018-0.0085). The association was moderated by cut point, with higher cut points typically producing stronger associations. No significant association between sedentary time and adiposity was observed.

CONCLUSIONS

The choice of accelerometer cut point may moderate the association between sedentary time and clustered metabolic risk, suggesting that direct comparisons of associations between studies using different cut points must be made with caution.

Bedroom media, sedentary time and screen-time in children: a longitudinal analysis

BACKGROUND

Having electronic media in the bedroom is cross-sectionally associated with greater screen-time in children, but few longitudinal studies exist. The aim of this study was to describe longitudinal patterns of ownership and examine cross-sectional and longitudinal associations of bedroom media with children's sedentary behaviour.

METHODS

Data are from the Sport, Physical activity and Eating behaviour: Environmental Determinants in Young people (SPEEDY) study, collected at 3 time-points: baseline (2007, T0; age 10.3 ± 0.3 years), 1-year (T1y) and 4-year (T4y) follow-up. For each assessment, 1512 (44.9% male), 715 (41.0% male), and 319 (48.3% male) participants provided valid accelerometer data. Outcome variables were accelerometer-assessed sedentary time and self-reported screen-time. The presence of a television or computer in the bedroom was self-reported by participants and a combined bedroom media score calculated as the sum of such items. Cross-sectional and longitudinal associations between bedroom media and each outcome were examined using multi-level linear regression.

RESULTS

Bedroom TV ownership fell from 70.9% at T0 to 42.5% at T4y. Having a TV in the bedroom (beta; 95% CI*100, T0: -1.17; -1.88, -0.46. T1y: -1.68; -2.67, -0.70) and combined bedroom media (T0: -0.76; -1.26, -0.27. T1y: -0.79; -1.51, -0.07) were negatively associated with objectively measured weekly sedentary time at T0 and T1y. Having a computer in the bedroom (beta; 95% CI, T0: 0.15; 0.02, 0.29. T4y: 0.35; 0.10, 0.60) and combined bedroom media (T0: 0.09: 0.01, 0.18. T4y: 0.20; 0.05, 0.34) were positively associated with screen-time at T0 and T4y. Relative to participants without a computer throughout the study, children that had a computer in their bedroom at T0 but not at T4y (beta; 95% CI for change in screen-time: -8.02; -12.75, -3.29) reported smaller increases in screen-time.

CONCLUSIONS

The bedroom media environment changes with age and exhibits a complex relationship with children's sedentary behaviour. Modifying children's bedroom media environment may impact upon screen-time but appears unlikely to influence overall sedentary time.

Association of physical activity and sedentary behavior with biological markers among U.S. pregnant women

BACKGROUND

To examine the association between objectively measured light-intensity and moderate-to-vigorous-intensity physical activity (MVPA), sedentary behaviors, and biological markers in a national sample of U.S. pregnant women, as few studies have examined these relationships among this population.

METHODS

The sample of noninstitutionalized U.S. civilians was selected by a complex, multistage probability design. Data from the 2003-2006 National Health and Examination Survey were used. Two hundred six pregnant women were included in the data analysis. Physical activity and sedentary data were objectively measured via accelerometry (ActiGraph 7164). Biomarker data was obtained in the mobile examination center from urine, blood samples, blood pressure, and anthropometric measurements. Urine and blood samples were obtained to determine pregnancy status, C-reactive protein (CRP), high-density lipoprotein (HDL) cholesterol, total cholesterol, and cotinine as well as fasting glucose, fasting triglycerides, and fasting low-density lipoprotein (LDL) cholesterol data. Multivariable regression was employed to examine the association between physical activity, sedentary behavior, and biomarker levels.

RESULTS

There was a positive association between sedentary behavior and CRP levels (beta coefficient [b]=0.001, p=0.02) and LDL cholesterol (b=0.12, p=0.02). There was an inverse association between light-intensity physical activity and CRP (b=-0.003; p=0.008) and diastolic blood pressure (b=-0.03; p=0.02), with those engaging in higher levels of MVPA having higher HDL cholesterol (b=6.7; p=0.01).

CONCLUSION

Physical activity and sedentary behavior were favorably associated with various biomarkers among pregnant women, suggesting that healthcare providers should encourage pregnant women to participate in safe forms of physical activity behaviors while also reducing their amount of time spent in sedentary behaviors.

Longitudinal levels and bouts of sedentary time among adolescent girls

Background

Adolescent girls are one of the most sedentary demographic groups. A better understanding of their accumulation of sedentary time is needed to inform future interventions. The purpose of this study was to examine the longitudinal levels and bouts of objectively measured sedentary time accumulated during different days of the week and periods of the weekday among a large sample of adolescent girls.

Methods

The results are based on 655 adolescent girls from the Girls in Sport Intervention and Research Project. Levels and bouts of sedentary time were derived from accelerometer data collected at baseline and 18-month follow-up. Total, weekday, weekend, school (i.e., morning bell to afternoon bell), after school (i.e., afternoon bell to 19:00), and evening (i.e. 19:01 to 23:59) sedentary time levels and bouts were calculated. Repeated-measures ANCOVAs were conducted to examine differences in sedentary time levels and bouts between days and time periods after adjusting for wear time, accelerometer model, and intervention group.

Results

Cross-sectional analyses revealed that levels and bouts of sedentary time were higher on weekdays compared to weekend days at baseline. Similar trends were observed at follow-up. In addition, percentage of wear time spent sedentary and bouts/hr of sedentary time were highest in the evening compared to the school and after school periods at both baseline and follow-up. Longitudinal analyses revealed that levels and bouts of sedentary time were higher at follow-up compared to baseline across the different days of the week and periods of the weekday examined, with the biggest increase (15%) occurring in the school period.

Conclusions

Future interventions targeting sedentary time among adolescent girls should consider developing strategies to reduce and break up prolonged sedentary time during the school day and in the evening.

Association between accelerometer-assessed sedentary behavior and objectively-measured hearing sensitivity in older US adults

OBJECTIVE

To examine the association between sedentary behavior and hearing sensitivity among a nationally representative sample of older US adults.

METHODS

Data from the 2003-2006 NHANES study was used, with 682 older adults (≥ 55 years) included in the study. Participants wore an ActiGraph 7164 accelerometer to measure sedentary behavior and hearing sensitivity was objectively measured in a sound-isolating room.

RESULTS

After adjustments, and comparisons to those with moderate or greater hearing loss, participants 65 years and older with hearing within normal limits (coefficient=-0.07; 95% CI: -0.12 to -0.01) engaged in less sedentary behavior; participants with mild hearing loss (coefficient=0.02; 95% CI: -0.01-0.07) did not differ in sedentary behavior than those with moderate or greater hearing loss. Sedentary behavior was not associated with hearing among those 55 and older.

CONCLUSIONS

Adults 65 and older with hearing in normal limits engage in less sedentary behavior than their counterparts with moderate or greater hearing loss. Evaluation and implementation of strategies to limit sedentary behaviors among older adults with greater hearing impairment, in particular, are needed.

Changes in physical activity among postpartum overweight and obese women: results from the KAN-DO Study

Few studies have assessed physical activity at multiple time points in the postpartum period or used both self-reported and objective measures of assessment. The purpose of this study was to describe physical activity and sedentary behavior at two time points in a cohort of overweight or obese postpartum women using both self-reported and objective measures. In total, 132 women completed physical activity assessments at a median of 24 weeks postpartum and again approximately 10 months later. At both time points, women wore an Actical accelerometer for one week and completed the Kaiser Physical Activity Survey. Adjusted Poisson regression models were used to determine whether physical activity changed over time for the cohort. Overall counts per minute and moderate to vigorous physical activity increased from baseline to 10 months later, although the absolute levels were modest (median 6.9 to 8.8 minutes/day). A median of 64%-71% at baseline and 63%-67% at follow-up of their monitored times were sedentary. More intensive interventions are needed to help postpartum women integrate physical activity and reduce sedentary behavior. [Supplementary material is available for this article. Go to the publisher's online edition of Women & Health for the following resource: three figures that show the distribution of physical activity and sedentary behavior by study periods among control participants].

Determinants of change in children's sedentary time

BACKGROUND

Understanding the determinants of sedentary time during childhood contributes to the development of effective intervention programmes.

PURPOSE

To examine family and home-environmental determinants of 1-year change in objectively measured sedentary time after-school and at the weekend.

METHODS

Participants wore accelerometers at baseline and 1 year later. Longitudinal data for after-school and weekend analyses were available for 854 (41.5%male, mean ± SD age 10.2 ± 0.3 years) and 718 (41.8%male, age 10.2 ± 0.3 years) participants. Information on 26 candidate determinants, including socioeconomic status (SES), availability of electronic media and parental rules for sedentary behaviours was self-reported by children or their parents at baseline. Change in the proportion of registered time spent sedentary was used as the outcome variable in multi-level linear regression models, adjusted for age, sex, body mass index and baseline sedentary time. Simple and multiple models were run and interactions with sex explored.

RESULTS

Children from higher socioeconomic status families exhibited greater increases in after-school (beta; 95% CI for change in % time spent sedentary 1.02; 0.37, 1.66) and weekend (1.42; 0.65, 2.18) sedentary time. Smaller increases in after-school sedentary time were observed in children with more siblings (-1.00; -1.69, -0.30), greater availability of electronic media (-0.81; -1.29, -0.33) and, for boys, more frequent family visits to the park (-1.89; -3.28, -0.51) and family participation in sport (-1.28; -2.54, -0.02). Greater maternal weekend screen-time (0.45; 0.08, 0.83) and, in girls, greater parental restriction on playing outside (0.91; 0.08, 1.74) were associated with larger increases in weekend sedentary time. The analytical sample was younger, more likely to be female, had lower BMI and was of higher SES than the original baseline sample.

CONCLUSIONS

Intervention strategies aimed at reducing parents' weekend screen-time, increasing family participation in sports or recreation (boys) and promoting freedom to play outside (girls) may contribute towards preventing the age-related increase in sedentary time.

Mobile computer application for promoting physical activity

Despite evidence that physical activity reduces the risk of falls and other causes of disability and death, the majority of older adults do not engage in physical activity on a regular basis. Mobile technology applications have emerged as potential resources for promoting physical activity behavior. This article describes features of a new application, Ready∼Steady, highlighting approaches used in its design and development, and implications for clinical practice. Iterative processes enabled the design, development, implementation, and evaluation of the application consistent with the wellness motivation theory, as well as established user-specific strategies and theoretical design principles. Implications in terms of potential benefits and constraints are discussed. Integrating technology that promotes health and wellness in the form of mobile computer applications is a promising adjunct to nursing practice.

Effect of physical activity and sedentary behavior on serum prostate-specific antigen concentrations: results from the National Health and Nutrition Examination Survey (NHANES), 2003-2006

OBJECTIVE

To examine the association between accelerometer-derived sedentary and physical activity and prostate-specific antigen (PSA) in a nationally representative sample of men in the United States.

PARTICIPANTS AND METHODS

Data from the 2003-2004 and 2005-2006 National Health and Nutrition Examination Survey cycles were used in the present study, with data from 1672 adult male participants used in the analyses. The manuscript was prepared between July 7, 2012, and September 26, 2012. Sedentary and physical activity was objectively measured using an accelerometer. Covariates included various demographic, dietary, biological, and immunologic variables including age, height, weight, body mass index, race/ethnicity, marital status, education, and poverty-income ratio; dietary fiber, fat, protein, and carbohydrate intake and total energy intake; vitamin C and vitamin E; alcohol intake; medication use; concentrations of cotinine, total cholesterol, and high-density lipoprotein cholesterol; blood pressure (elevated or not elevated); diabetes; C-reactive protein; and white blood cell count and number of basophils and eosinophils.

RESULTS

Only after controlling for all covariates, for every 1-hour increase in sedentary behavior, participants were 16% more likely to have an elevated PSA concentration (odds ratio, 1.16 [95% CI, 1.06-1.27]; P=.001). For every 1-hour increase in light physical activity, participants were 18% less likely to have an elevated PSA concentration (odds ratio, 0.82 [95% CI, 0.68-1.00]; P=.05).

CONCLUSION

Individuals who engage in more sedentary behavior and lower levels of light physical activity have higher PSA concentrations. Future studies are needed to better identify the potential underlying mechanisms delineating the association between sedentary and physical activity and PSA concentration.

Patterns of sedentary behaviours in Irish female adolescents

Engagement in excessive sedentary behaviour represents a health risk for adolescents. The current study aimed to investigate patterns of sedentary behaviour amongst Irish female adolescents aged between 15 and 19 years old. 314 adolescents completed a questionnaire on their sedentary behaviour habits, health behaviours (physical activity, smoking, and alcohol use), enjoyment of sedentary behaviour, value on health, and sedentary facilitators in their home. Parents provided information on parental education, the child's weight and height, and parental sedentary behaviour habits. Cluster analysis found that five distinct sedentary clusters existed in this sample: Unproductive/Social Sedentary, Reading/Productive Behaviours, Mixed Sedentary Interests, Restricted Interests/High Television, and Academic Sedentary. The clusters differed on smoking and alcohol use, enjoyment of sedentary behaviour, and parental engagement in sedentary behaviour. The findings from this study support the use of a socio-ecological framework for investigating the development of sedentary behaviour patterns.

Patterns of physical activity and sedentary behaviour in preschool children

BACKGROUND

Little is known about patterns of sedentary behavior (SB) and physical activity among preschoolers. Therefore, in this observational study patterns of SB and moderate-to-vigorous physical activity (MVPA) were examined in detail throughout the week in preschool-aged boys and girls.

METHODS

A sample of 703 Melbourne preschool children (387 boys; 4.6 ± 0.7 y) were included in data analysis. SB and MVPA data were collected using accelerometry over an eight-day period. Percentage of time per hour in SB and in MVPA between 08:00 h and 20:00 h was calculated. Multi-level logistic regression models were created to examine the hour-by-hour variability in SB and MVPA for boys and girls across weekdays and weekend days. Odds ratios (OR) were calculated to interpret differences in hour-by-hour SB and MVPA levels between boys and girls, and between weekdays and weekend days.

RESULTS

The highest SB levels co-occurred with the lowest MVPA levels from the morning till the early afternoon on weekdays, and during the morning and around midday on weekends. Besides, participation in SB was the lowest and participation in MVPA was the highest from the mid afternoon till the evening on weekdays and weekend days. The variability across the hours in SB and, especially, in MVPA was rather small throughout weekdays and weekends. These patterns were found in both boys and girls. During some hours, girls were found to be more likely than boys to demonstrate higher SB levels (OR from 1.08 to 1.16; all p < 0.05) and lower MVPA levels (OR from 0.75 to 0.88; all p < 0.05), but differences were small. During weekends, hour-by-hour SB levels were more likely to be lower (OR from 0.74 to 0.98; all p < 0.05) and hour-by-hour MVPA levels were more likely to be higher (OR from 1.15 to 1.50; all p < 0.05), than during weekdays, in boys and girls.

CONCLUSION

Entire weekdays, especially from the morning till the early afternoon, and entire weekend days are opportunities to reduce SB and to promote MVPA in preschool-aged boys and girls. Particularly weekdays hold the greatest promise for improving SB and MVPA. No particular time of the week was found where one sex should be targeted.

Evidence that women meeting physical activity guidelines do not sit less: an observational inclinometry study

Background

The inactivity physiology paradigm proposes that sedentary behaviors, including sitting too much, are independent of the type of physical activity delineated for health in the Physical Activity Guidelines for Americans. Thus, we hypothesized that, when accounting for behaviors across the entire day, variability in the amount of time spent sitting would be independent of the inter-and intra-individual time engaged in sustained moderate-to-vigorous physical activity (MVPA).

Methods

Ninety-one healthy women, aged 40–75 years, completed a demographic questionnaire and assessment of height and weight. Participants wore the activPAL activity monitor for one week and time (minutes/day) spent sitting, standing, stepping, and in sustained bouts (bouts ≥10 minutes) of MVPA were quantified. The women were then stratified into groups based on weekly sustained MVPA. Additionally, each day of data collection for each participant was classified as either a “sufficient” MVPA day (≥ 30 min of MVPA) or an “insufficient” MVPA day for within-participant analyses.

Results

Time spent sitting, standing, and in incidental non-exercise stepping averaged 64, 28, and 11 hrs/week, respectively, and did not differ between groups with individuals meeting/exceeding the current exercise recommendation of 150 min/week of sustained MVPA in ≥10 minutes bouts (M = 294 min/week, SD = 22) compared to those with none or minimal levels (M= 20min/week, SD = 4). Time spent sitting (M = 9.1 hr/day, SD = 0.19 vs. M = 8.8 hr/day, SD = 0.22), standing (M = 3.9 hr/day, SD = 0.16 vs. M = 3.9 hr/day, SD = 0.15), and in intermittent stepping (M = 1.6 hr/day, SD = 0.07 vs. M = 1.6 hr/day, SD = 0.06) did not differ between days with (~55 min/day) and without recommended MVPA.

Conclusions

This study provides the first objective evidence that participation in sustained MVPA is unrelated to daily sitting duration in relatively healthy, middle and older-aged women. More research is needed to extend these findings to other populations and to inform distinct behavioral recommendations focused on sedentary time.

Methods of Measurement in epidemiology: sedentary Behaviour

BACKGROUND

Research examining sedentary behaviour as a potentially independent risk factor for chronic disease morbidity and mortality has expanded rapidly in recent years.

METHODS

We present a narrative overview of the sedentary behaviour measurement literature. Subjective and objective methods of measuring sedentary behaviour suitable for use in population-based research with children and adults are examined. The validity and reliability of each method is considered, gaps in the literature specific to each method identified and potential future directions discussed.

RESULTS

To date, subjective approaches to sedentary behaviour measurement, e.g. questionnaires, have focused predominantly on TV viewing or other screen-based behaviours. Typically, such measures demonstrate moderate reliability but slight to moderate validity. Accelerometry is increasingly being used for sedentary behaviour assessments; this approach overcomes some of the limitations of subjective methods, but detection of specific postures and postural changes by this method is somewhat limited. Instruments developed specifically for the assessment of body posture have demonstrated good reliability and validity in the limited research conducted to date. Miniaturization of monitoring devices, interoperability between measurement and communication technologies and advanced analytical approaches are potential avenues for future developments in this field.

CONCLUSIONS

High-quality measurement is essential in all elements of sedentary behaviour epidemiology, from determining associations with health outcomes to the development and evaluation of behaviour change interventions. Sedentary behaviour measurement remains relatively under-developed, although new instruments, both objective and subjective, show considerable promise and warrant further testing.

Non-occupational sitting and mental well-being in employed adults

BACKGROUND

Emerging evidence suggests that sedentary behaviour may be adversely associated with physical health, but few studies have examined the association with mental well-being.

PURPOSE

This study examined the association of four non-occupational sedentary behaviours, individually and in total, with mental well-being in employed adults.

METHODS

Baseline data from the evaluation of Well@Work, a national workplace health promotion project conducted in the UK, were used. Participants self-reported sitting time whilst watching television, using a computer, socialising and travelling by motorised transport. Mental well-being was assessed by the 12-item version of the general health questionnaire. Analyses were conducted using multiple linear regression.

RESULTS

In models adjusted for multiple confounders, TV viewing, computer use and total non-occupational sitting time were adversely associated with general health questionnaire-12 assessed mental well-being in women. Computer use only was found to be adversely associated with mental well-being in men.

CONCLUSION

Sedentary behaviour may be adversely associated with mental well-being in employed adults. The association may be moderated by gender.

A hitchhiker's guide to assessing sedentary behaviour among young people: deciding what method to use

OBJECTIVE

To provide a user's guide for selecting an appropriate method to assess sedentary behaviours among children and adolescents.

DESIGN

While recommendations regarding specific instruments are not provided, the guide offers information about key attributes and considerations for objective (accelerometry; inclinometers; direct observation; screen monitoring devices) and subjective (self-report; parent report; and time use diaries/logs) approaches to assess sedentary behaviour Attributes of instruments and other factors to be considered in the selection of assessment instruments include: population (age); sample size; respondent burden; method/delivery mode; assessment time frame; physical activity information required (data output); data management; measurement error; cost (instrument and administration) and other limitations.

METHODS

Expert consensus among members of the Australasian Child and Adolescent Obesity Research Network's (ACAORN) Physical Activity and Sedentary Behaviour Special Interest Group.

RESULTS

We developed decision flow charts to assist researchers and practitioners select an appropriate method of assessing sedentary behaviour, identified attributes of each method and described five real-life scenarios to illustrate considerations associated with the selection of each method of measurement.

CONCLUSIONS

It is important that researchers, practitioners and policy makers understand the strengths and limitations of different methods of assessing sedentary behaviour among youth, and are guided on selection of the most appropriate instrument/s to suit their needs.

Comparison of Actical and activPAL measures of sedentary behaviour in preschool children

OBJECTIVES

The purpose of this study was to examine the convergent validity of the Actical and activPAL to measure sedentary behaviour (SB) and non-SB in preschoolers in a free-living environment.

DESIGN

A convenience sample of 49 preschoolers (22 boys; 4.0 ± 0.5 years) from six early childhood centres in Auckland, New Zealand were included in data analysis.

METHODS

Participants wore a hip-mounted Actical and a thigh-mounted activPAL accelerometer simultaneously during centre attendance for one day and data were collected in 15s epochs. Bland-Altman tests were used to assess differences in group mean minutes and percentage of time in (non-)SB between both monitors. Agreement between binary coded (SB vs. non-SB) 15s-by-15s Actical and activPAL data was evaluated by calculating percentage agreement and κ statistic.

RESULTS

The monitors were worn on average for 294.8 ± 46.3 min resulting in a total of 57,780 15s epochs. Bland-Altman tests suggested a small group mean difference in (non-)SB (1.3 min; 0.1%) and a wide prediction interval (121.3 min; 39.2%). No obvious systematic bias was observed in the Bland-Altman plot. Percentage agreement between the 15s-by-15s Actical and activPAL data of all participants was 73.0% (inter-child range: 36.8-93.8%). The κ statistic showed moderate agreement with a value of 0.46 (95% CI: 0.45-0.47).

CONCLUSIONS

Although the group mean estimate of (non-)SB was similar between the Actical and activPAL, the output of both monitors cannot be considered convergent as meaningful random disagreement was found between both monitors.

Sedentary behavior and adiposity-associated inflammation: the Multi-Ethnic Study of Atherosclerosis

BACKGROUND

Sedentary behavior is associated with adiposity and cardiometabolic risk.

PURPOSE

To determine the associations between sedentary behavior and measures of adiposity-associated inflammation.

METHODS

Between 2002 and 2005, a total of 1543 Multi-Ethnic Study of Atherosclerosis participants completed detailed health history questionnaires, underwent physical measurements, and had blood assayed for adiponectin, leptin, tumor necrosis factor-alpha (TNF-α) and resistin. Analyses included linear regression completed in 2010. The mean age was 64.3 years and nearly 50% were female. Forty-one percent were non-Hispanic white, 24% Hispanic-American, 20% African-American, and 14% Chinese-American.

RESULTS

In linear regression analyses and with adjustment for age, gender, ethnicity, education, BMI, smoking, alcohol consumption, hypertension, diabetes mellitus, dyslipidemia, hormone therapy and waist circumference, sedentary behavior was associated with higher natural log ("ln") of leptin and ln TNF-α but a lower ln adiponectin-to-leptin ratio (β=0.07, β=0.03 and -0.07, p<0.05 for all). Compared to the first tertile, and after the same adjustment, the second and third tertiles of sedentary behavior were associated with higher levels of ln leptin (β=0.11 and β=0.12, respectively; p<0.05 for both) but lower levels of the adiponectin-to-leptin ratio (β=-0.09 and -0.11, respectively; p<0.05 for both).

CONCLUSIONS

Sedentary behavior is associated with unfavorable levels of adiposity-associated inflammation.