Jannique G.Z. van Uffelen

Occupational sitting and health risks: a systematic review

CONTEXT Emerging evidence suggests that sedentary behavior (i.e., time spent sitting) may be negatively associated with health. The aim of this study was to systematically review the evidence on associations between occupational sitting and health risks. EVIDENCE ACQUISITION Studies were identified in March-April 2009 by literature searches in PubMed, PsycINFO, CENTRAL, CINAHL, EMBASE, and PEDro, with subsequent related-article searches in PubMed and citation searches in Web of Science. Identified studies were categorized by health outcome. Two independent reviewers assessed methodologic quality using a 15-item quality rating list (score range 0-15 points, higher score indicating better quality). Data on study design, study population, measures of occupational sitting, health risks, analyses, and results were extracted. EVIDENCE SYNTHESIS 43 papers met the inclusion criteria (21% cross-sectional, 14% case-control, 65% prospective); they examined the associations between occupational sitting and BMI (n=12); cancer (n=17); cardiovascular disease (CVD, n=8); diabetes mellitus (DM, n=4); and mortality (n=6). The median study-quality score was 12 points. Half the cross-sectional studies showed a positive association between occupational sitting and BMI, but prospective studies failed to confirm a causal relationship. There was some case-control evidence for a positive association between occupational sitting and cancer; however, this was generally not supported by prospective studies. The majority of prospective studies found that occupational sitting was associated with a higher risk of DM and mortality. CONCLUSIONS Limited evidence was found to support a positive relationship between occupational sitting and health risks. The heterogeneity of study designs, measures, and findings makes it difficult to draw definitive conclusions at this time.

The effects of exercise on cognition in older adults with and without cognitive decline: A systematic review

Objective:To systematically review the effect of physical exercise on cognition in older adults with and without cognitive decline. Data Sources:Randomized controlled trials were identified by literature searches in PubMed, EMBASE, CENTRAL, PsycINFO, and AgeLine. Study Selection:Papers were included on the basis of predefined inclusion criteria. Data Extraction:Data on study population, exercise intervention, and effectiveness were extracted. Two independent reviewers assessed methodological quality. Data Synthesis:Twenty-three studies were included-15 among cognitively healthy subjects and 8 among subjects with cognitive decline. Seven studies were qualified as high-quality studies, 2 in cognitively healthy subjects and 5 in subjects with cognitive decline. In cognitively healthy subjects, significant beneficial intervention effects were observed in 5 studies on information processing, executive function, or memory. Interventions in these studies included aerobic exercise only (n = 2); strength exercise (n = 1); strength and balance exercise (n = 1); or all-round exercise including aerobic, strength, balance and flexibility training (n = 1). In subjects with cognitive decline, 5 studies observed beneficial effects on general cognition, executive functions, and memory. Interventions included aerobic (n = 3) or strength exercise combined with flexibility or balance exercise (n = 2). Conclusions:Beneficial effects of various exercise programs on aspects of cognition have been observed in studies among subjects with and without cognitive decline. The majority of the studies, however, did not find any effect. The small number of included studies; lack of high-quality studies; and the large variability in study populations, exercise protocols, and outcome measures complicate interpretation of the results. More high-quality trials are needed to assess the effects of different types of exercise on cognitive function in older adults with and without cognitive decline.

Are workplace interventions to reduce sitting effective? A systematic review

OBJECTIVE To systematically review the effectiveness of workplace interventions for reducing sitting. METHODS Studies published up to April 2009 were identified by literature searches in multiple databases. Studies were included if they were interventions to increase energy expenditure (increase physical activity or decrease sitting); were conducted in a workplace setting; and specifically measured sitting as a primary or secondary outcome. Two independent reviewers assessed methodological quality of the included studies, and data on study design, sample, measures of sitting, intervention and results were extracted. RESULTS Six studies met the inclusion criteria (five randomised trials and one pre-post study). The primary aim of all six was to increase physical activity; all had reducing sitting as a secondary aim. All used self-report measures of sitting; one specifically assessed occupational sitting time; the others used measures of general sitting. No studies showed that sitting decreased significantly in the intervention group, compared with a control or comparison group. CONCLUSION Currently, there is a dearth of evidence on the effectiveness of workplace interventions for reducing sitting. In light of the growing body of evidence that prolonged sitting is negatively associated with health, this highlights a gap in the scientific literature that needs to be addressed.

Physical and psychosocial benefits of yoga in cancer patients and survivors, a systematic review and meta-analysis of randomized controlled trials

BackgroundThis study aimed to systematically review the evidence from randomized controlled trials (RCTs) and to conduct a meta-analysis of the effects of yoga on physical and psychosocial outcomes in cancer patients and survivors.MethodsA systematic literature search in ten databases was conducted in November 2011. Studies were included if they had an RCT design, focused on cancer patients or survivors, included physical postures in the yoga program, compared yoga with a non-exercise or waitlist control group, and evaluated physical and/or psychosocial outcomes. Two researchers independently rated the quality of the included RCTs, and high quality was defined as >50% of the total possible score. Effect sizes (Cohen’s d) were calculated for outcomes studied in more than three studies among patients with breast cancer using means and standard deviations of post-test scores of the intervention and control groups.ResultsSixteen publications of 13 RCTs met the inclusion criteria, of which one included patients with lymphomas and the others focused on patients with breast cancer. The median quality score was 67% (range: 22–89%). The included studies evaluated 23 physical and 20 psychosocial outcomes. Of the outcomes studied in more than three studies among patients with breast cancer, we found large reductions in distress, anxiety, and depression (d = −0.69 to −0.75), moderate reductions in fatigue (d = −0.51), moderate increases in general quality of life, emotional function and social function (d = 0.33 to 0.49), and a small increase in functional well-being (d = 0.31). Effects on physical function and sleep were small and not significant.ConclusionYoga appeared to be a feasible intervention and beneficial effects on several physical and psychosocial symptoms were reported. In patients with breast cancer, effect size on functional well-being was small, and they were moderate to large for psychosocial outcomes.

Dose–response relationships between physical activity, walking and health-related quality of life in mid-age and older women

Background Although physical activity is associated with health-related quality of life (HRQL), the nature of the dose–response relationship remains unclear. Objectives To examine the concurrent and prospective dose–response relationships between total physical activity (TPA) and (only) walking with HRQL in two age cohorts of women. Methods Participants were 10 698 women born in 1946–1951 and 7646 born in 1921–1926, who completed three mailed surveys for the Australian Longitudinal Study on Womens Health. They reported weekly TPA minutes (sum of walking, moderate and vigorous minutes). HRQL was measured with the Medical Outcomes Study Short-Form 36 Health Status Survey (SF-36). Linear mixed models, adjusted for socio-demographic and health-related variables, were used to examine associations between TPA level (none, very low, low, intermediate, sufficient, high and very high) and SF-36 scores. For women who reported walking as their only physical activity, associations between walking and SF-36 scores were also examined. Results Curvilinear trends were observed between TPA and walking with SF-36 scores. Concurrently, HRQL scores increased significantly with increasing TPA and walking, in both cohorts, with increases less marked above sufficient activity levels. Prospectively, associations were attenuated although significant and meaningful improvements in physical functioning and vitality were observed across most TPA and walking categories above the low category. Conclusion For women in their 50s–80s without clinical depression, greater amounts of TPA are associated with better current and future HRQL, particularly physical functioning and vitality. Even if walking is their only activity, women, particularly those in their 70s–80s, have better HRQL.

Sitting-Time, Physical Activity, and Depressive Symptoms in Mid-Aged Women

BACKGROUND Associations of sitting-time and physical activity with depression are unclear. PURPOSE To examine concurrent and prospective associations between both sitting-time and physical activity with prevalent depressive symptoms in mid-aged Australian women. METHODS Data were from 8950 women, aged 50-55 years in 2001, who completed mail surveys in 2001, 2004, 2007, and 2010. Depressive symptoms were assessed using the Center for Epidemiological Studies Depression questionnaire. Associations between sitting-time (≤ 4 hours/day, >4-7 hours/day, >7 hours/day) and physical activity (none, some, meeting guidelines) with depressive symptoms (symptoms/no symptoms) were examined in 2011 in concurrent and lagged mixed-effect logistic modeling. Both main effects and interaction models were developed. RESULTS In main effects modeling, women who sat >7 hours/day (OR=1.47, 95% CI=1.29, 1.67) and women who did no physical activity (OR=1.99, 95% CI=1.75, 2.27) were more likely to have depressive symptoms than women who sat ≤ 4 hours/day and who met physical activity guidelines, respectively. In interaction modeling, the likelihood of depressive symptoms in women who sat >7 hours/day and did no physical activity was triple that of women who sat ≤ 4 hours/day and met physical activity guidelines (OR 2.96, 95% CI=2.37, 3.69). In prospective main effects and interaction modeling, sitting-time was not associated with depressive symptoms, but women who did no physical activity were more likely than those who met physical activity guidelines to have future depressive symptoms (OR=1.26, 95% CI=1.08, 1.47). CONCLUSIONS Increasing physical activity to a level commensurate with guidelines can alleviate current depression symptoms and prevent future symptoms in mid-aged women. Reducing sitting-time may ameliorate current symptoms.

Are Active Australia physical activity questions valid for older adults

OBJECTIVE The Active Australia Survey (AAS) is used for physical activity (PA) surveillance in the general Australian adult population, but its validity in older adults has not been evaluated. Our aim was to examine the convergent validity of the AAS questions in older adults. DESIGN The AAS was validated against pedometer step counts as an objective measure of PA, self-reported physical function, and a step-test to assess cardiorespiratory fitness. METHOD Participants were community-dwelling adults, aged 65-89 y, with the ability to walk 100 m. They completed a self-administered AAS and the step-test in one interview. One week earlier, they completed the Short Form-36 physical function subscale. Between these two interviews, they each wore a YAMAX Digiwalker SW200 pedometer and recorded daily steps. Using the AAS data, daily walking minutes and total PA minutes (walking, moderate-intensity PA and vigorous-intensity PA) were compared with the validity measures using Spearman rank-order correlations. Fifty-three adults completed the study. RESULTS Median daily walking minutes were 34.2 (interquartile range [IQR] 17.1, 60.0), and median daily total PA minutes were 68.6 (IQR 31.4, 113.6). Walking and total PA minutes were both moderately correlated with pedometer steps (Spearman correlation r=0.42, p=0.003, for each) but not with step-test seconds to completion (r=-0.11, p=0.44; r=-0.25, p=0.08, respectively). Total PA minutes were significantly correlated with physical function scores (r=0.39, p=0.004), but walking minutes were not (r=0.15, p=0.29). CONCLUSIONS This initial examination of the psychometric properties of the AAS for older adults suggests that this surveillance tool has acceptable convergent validity for ambulatory, community-dwelling older adults.

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.

Associations of physical activity and screen-time on health related quality of life in adults.

BACKGROUND Associations between the combined effect of physical activity and screen based activities on health related quality of life remain largely undetermined. METHODS During 2008-2010, cross-sectional data for self-reported health related quality of life, physical activity, and screen-time were collected for 3796 Australian adults. Logistic regression was conducted to examine associations for six combinations of physical activity (none, insufficient, and sufficient), and screen-time (low and high) on health related quality of life. RESULTS In comparison to the reference category (sufficient physical activity and low screen-time) men and women who reported no physical activity and either high (OR=4.52, 95% CI 2.82-7.25) or low (OR=2.29, 95% CI 1.37-3.80) screen-time, were significantly more likely to report over 14 unhealthy days. Men reporting either; no physical activity and high (OR=3.15, 95% CI 1.92-5.15), or low (OR=2.17, 95% CI 1.30-3.63) screen-time; insufficient physical activity and high (OR=1.68, 95% CI 1.08-2.60), or low (OR=1.79, 95% CI 1.14-2.82) screen-time were more likely to rate their health as poor or fair. In women this was significant for those who reported no physical activity and high screen-time (OR=1.98, 95% CI, 1.19-3.31). CONCLUSIONS Results suggest that the combination of no physical activity and high screen-time demonstrated the greatest negative impact on health related quality of life.

Sitting Time Is Associated With Weight, but Not With Weight Gain in Mid-Aged Australian Women

The aim of this study was to examine the associations between sitting time, weight, and weight gain in Australian women born in 1946–1951. Data were from 8,233 women who completed surveys for the Australian Longitudinal Study on Womens Health (ALSWH) in 2001, 2004, and 2007. Associations between sitting time and weight, and between sitting time and weight change in each 3‐year period were examined using repeated measures modeling. The associations between weight and change in sitting time were also examined. Analyses were stratified for BMI categories: normal weight (18.5 ≤ BMI < 25), overweight (25 ≤ BMI < 30), and obese (BMI ≥ 30). In cross‐sectional models, each additional hour of sitting time was associated with 110 g (95% confidence interval (CI): 40–180) and 260 g (95% CI: 140–380) additional weight in overweight and obese women, respectively (fully adjusted model). In prospective analyses, sitting time was not consistently associated with weight change, after adjustment for other variables, and weight was not associated with change in sitting time over successive 3‐year periods. In conclusion, although the cross‐sectional associations between sitting time and weight were evident in overweight and obese women, there was no consistent association between sitting time and weight gain. A potential explanation is that prospective associations may only be apparent over longer periods of time. These results do not support a role for reducing sitting time as a short‐term means of weight control in mid‐aged women.