Dafna Merom

Cross-sectional associations between occupational and leisure-time sitting, physical activity and obesity in working adults.

AIM To examine associations between occupational and leisure-time sitting, physical activity and obesity in working adults. METHODS We analyzed data from workers from the 2007-08 Australian National Health Survey (n=10,785). Participants reported their activity at work (mostly sitting, standing, walking, or heavy labor), transport-related walking, leisure-time sitting and physical activity. Body mass index was objectively measured. Adjusted Cox proportional hazard regression models examined associations between occupational activity category, leisure-time sitting, physical activity and obesity risk. RESULTS Substantial proportions of men (42%) and women (47%) mostly sit at work. Workers with sitting jobs were significantly more likely to be sufficiently active during leisure-time than workers with mostly standing, walking or heavy labor jobs (RR=0.88, 0.80, 0.86 respectively). Workers with mostly sitting jobs had significantly higher overweight/obesity risk than workers with mostly standing jobs (RR=0.88, 95% CI: 0.82-0.95) independent of physical activity and leisure-time sitting. Workers with leisure-time sitting of less than four hours per day had significantly lower obesity risk than workers with four or more hours per day of leisure-time sitting (RR=0.77, 95%CI: 0.69-0.87) independent of physical activity and occupational activity. CONCLUSIONS Sitting time and physical activity are independently associated with obesity. Leisure-time sitting may have a stronger association with obesity risk than occupational sitting.

Can social dancing prevent falls in older adults? a protocol of the Dance, Aging, Cognition, Economics (DAnCE) fall prevention randomised controlled trial

AbstractBackgroundFalls are one of the most common health problems among older people and pose a major economic burden on health care systems. Exercise is an accepted stand-alone fall prevention strategy particularly if it is balance training or regular participation in Tai chi. Dance shares the ‘holistic’ approach of practices such as Tai chi. It is a complex sensorimotor rhythmic activity integrating multiple physical, cognitive and social elements. Small-scale randomised controlled trials have indicated that diverse dance styles can improve measures of balance and mobility in older people, but none of these studies has examined the effect of dance on falls or cognition. This study aims to determine whether participation in social dancing: i) reduces the number of falls; and ii) improves cognitive functions associated with fall risk in older people.Methods/designA single-blind, cluster randomised controlled trial of 12 months duration will be conducted. Approximately 450 participants will be recruited from 24 self-care retirement villages that house at least 60 residents each in Sydney, Australia. Village residents without cognitive impairment and obtain medical clearance will be eligible. After comprehensive baseline measurements including physiological and cognitive tests and self-completed questionnaires, villages will be randomised to intervention sites (ballroom or folk dance) or to a wait-listed control using a computer randomisation method that minimises imbalances between villages based on two baseline fall risk measures. Main outcome measures are falls, prospectively measured, and the Trail Making cognitive function test. Cost-effectiveness and cost-utility analyses will be performed.DiscussionThis study offers a novel approach to balance training for older people. As a community-based approach to fall prevention, dance offers older people an opportunity for greater social engagement, thereby making a major contribution to healthy ageing. Providing diversity in exercise programs targeting seniors recognises the heterogeneity of multicultural populations and may further increase the number of taking part in exercise.Trial registrationAustralian New Zealand Clinical Trials Registry ACTRN12612000889853 The trial is now in progress with 12 villages already have been randomised.

Time spent playing outdoors after school and its relationship with independent mobility: a cross-sectional survey of children aged 10–12 years in Sydney, Australia

BackgroundTime spent outdoors is positively associated with physical activity and has been suggested as a proxy for physical activity of children. The role of childrens independence in physical activity and time spent outdoors is less understood. This study aimed to assess how much time children spent playing outdoors after school, and to explore the relationship between outdoor play and independence among children aged 10–12 years.MethodChildren recorded how much time they spent playing outdoors or watching TV/videos or playing computer games after school using a five-day diary, and also reported whether they were allowed to walk on their own in their neighbourhood as an indicator of their independent mobility. Parents were surveyed on family demographics and perception of neighbourhood safety. The surveys were conducted in late 2006 as part of the Central Sydney Walk to School program which involved 1975 children and their parents from 24 primary schools. Factors associated with time spent playing outdoors were determined by logistic regression modelling.ResultsThirty-seven per cent of children spent less than half an hour a day playing outdoors after school, and 43% spent more than 2 hours a day watching TV, videos or playing computer games. Forty-eight per cent of children were allowed to walk on their own near where they lived. Childrens independent mobility was significantly associated with outdoor play after adjusting for other confounders. Compared with those who were never allowed to walk on their own near where they lived, students who were allowed to walk on their own were significantly more likely to spend more than half an hour a day playing outdoors after school with an adjusted odds ratio of 2.6, 95% CI 1.84–3.58, P < 0.001.ConclusionThe findings that a significant proportion of children spend less than half an hour a day playing outdoors after school and have excessive screen time have important implications for physical activity promotion and obesity prevention. The study also suggests that childrens independent mobility should be considered in research and evaluation into childrens play and physical activity. Environments that promote greater independent mobility in children may increase their physical activity levels and hence reduce their risk of overweight/obesity.

Does playground improvement increase physical activity among children? A quasi-experimental study of a natural experiment.

Outdoor recreational spaces have the potential to increase physical activity. This study used a quasi-experimental evaluation design to determine how a playground renovation impacts usage and physical activity of children and whether the visitations correlate with childrens physical activity levels and parental impressions of the playground. Observational data and intercept interviews were collected simultaneously on park use and park-based activity among playground visitors at pre- and postrenovation at an intervention and a comparison park during three 2-hour periods each day over two weeks. No detectable difference in use between parks was observed at followup. In the intervention park, attendance increased among boys, but decreased among girls although this (nonsignificant) decline was less marked than in the comparison park. Following renovation, there was no detectable difference between parks in the number of children engaged in MVPA (interaction between park and time: P = 0.73). At the intervention park, there was a significant decline in girls engaging in MVPA at followup (P = 0.04). Usage was correlated with parental/carer perceptions of playground features but not with physical activity levels. Renovations have limited the potential to increase physical activity until factors influencing usage and physical activity behavior are better understood.

Advances in Population Surveillance for Physical Activity and Sedentary Behavior: Reliability and Validity of Time Use Surveys

Many countries conduct regular national time use surveys, some of which date back as far as the 1960s. Time use surveys potentially provide more detailed and accurate national estimates of the prevalence of sedentary and physical activity behavior than more traditional self-report surveillance systems. In this study, the authors determined the reliability and validity of time use surveys for assessing sedentary and physical activity behavior. In 2006 and 2007, participants (n = 134) were recruited from work sites in the Australian state of New South Wales. Participants completed a 2-day time use diary twice, 7 days apart, and wore an accelerometer. The 2 diaries were compared for test-retest reliability, and comparison with the accelerometer determined concurrent validity. Participants with similar activity patterns during the 2 diary periods showed reliability intraclass correlations of 0.74 and 0.73 for nonoccupational sedentary behavior and moderate/vigorous physical activity, respectively. Comparison of the diary with the accelerometer showed Spearman correlations of 0.57-0.59 and 0.45-0.69 for nonoccupational sedentary behavior and moderate/vigorous physical activity, respectively. Time use surveys appear to be more valid for population surveillance of nonoccupational sedentary behavior and health-enhancing physical activity than more traditional surveillance systems. National time use surveys could be used to retrospectively study nonoccupational sedentary and physical activity behavior over the past 5 decades.

Prevalence and correlates of participation in fall prevention exercise/physical activity by older adults.

OBJECTIVE To examine older peoples participation in fall prevention exercise/physical activities. METHODS Participants comprised 5,681 randomly selected older people (≥ 65 years) who took part in the 2009 New South Wales (Australia) Fall Prevention telephone survey (61% response-rate). The instrument consisted of 11 prompted activities including two separate questions on participation in strength and balance training. Tai chi, dance, team sports, golf, bowls and specific balance training were classified as balance-challenging activities. Correlates of low participation were examined using multivariable logistic regression. RESULTS One in eight older people (12.0%, 95% CI: 11.0-13.0) participated in strength training, 6.0% (95% CI: 5.2-6.7) participated in balance training and 21.8% (95% CI: 20.5-23.0) participated in balance-challenging activities. Adherence to public health recommendations (≥ 2 days/week) for strength or balance-challenging activities was reported by 21.0% (95% CI: 9.8-22.2) with 5.3% adhering to both forms. Engagements in strength or in balance-challenging activities were lower among those who had low education (<high-school), lived in disadvantaged neighbourhoods, were obese, had fair/poor self-rated health, had problems with walking or used a walking aid or had fallen in the past year. CONCLUSION Participation in best practice exercise to prevent falls is low. Population-based approaches and targeted strategies for high-risk group are needed.

Recreational facilities and leisure-time physical activity : an analysis of moderators and self-efficacy as a mediator

OBJECTIVE To examine socio-demographic and psychosocial moderators, and self-efficacy as a mediator of the cross-sectional relationships between having access to recreational facilities and leisure-time physical activity (LTPA); to investigate the extent to which the environment-LTPA associations could be explained by self-selection to neighborhoods. DESIGN A two-stage stratified sampling design was used to recruit 2,650 adults (aged 20-65) from 32 urban communities varying in walkability and socioeconomic status. Participants reported perceived access to facilities and home equipment for LTPA, weekly minutes of LTPA, self-efficacy for and enjoyment of LTPA, reasons for neighborhood selection, and socio-demographic characteristics. MAIN OUTCOME MEASURES Self-reported recreational walking and other forms of moderate-to-vigorous LTPA expressed in MET-minutes. RESULTS Specific types of recreational facilities were independently associated with LTPA. Age, education, being overweight/obese, reasons for neighborhood selection, enjoyment of, and self-efficacy for LTPA moderated these relationships. Self-efficacy was not a significant mediator of these cross-sectional associations. CONCLUSION These findings have potentially significant implications for the planning of environmental interventions aimed at increasing population-level LTPA particularly in those who are less attitudinally inclined to being physically active.

Public health perspectives on household travel surveys : active travel between 1997 and 2007

BACKGROUND Active travel is beneficial to public health, but longitudinal population surveillance data on this behavior are limited. PURPOSE This study aims to monitor active travel at different health-enhancing thresholds and to identify trip purposes that contributed to health by using transport survey data. METHODS The continuous Sydney Greater Metropolitan Area Household Travel Survey (1997-2007) was analyzed in 2009. Each year, approximately 3250 households were randomly sampled (67% average response rate). All trips undertaken for a nominated 24-hour period were recorded for every household member during a face-to-face interview. Trips were coded by mode, purpose, duration, and street distance. The yearly prevalence and temporal change for adults (> or =15 years) were calculated for any walking and cycling (i.e., > or =1 trip per day) and by health-enhancing indicators dependent on trip duration (> or =10 minutes) and amount (i.e., > or =30 minutes/day). RESULTS Significant increasing trends were observed for all walking indicators, with a peak in 2005, where 39.2% walked, 24.7% walked > or =1 trip of > or =10 minutes, and 14.3% or 17.8% achieved the recommended 30 minutes a day with or without stipulation on trip duration, respectively. Health-enhancing walking increased in most population subgroups. Cycling prevalence was low (<1.5%) but with significant increasing trends in all indicators and in selected subgroups. Utilitarian cycling trips were of long duration (medians=10-15 minutes) whereas utilitarian walking trips were shorter (medians=5-7 minutes). CONCLUSIONS Transportation surveys can be used to assess the contribution of active travel to changes in physical activity levels assessed by public health surveillance and to identify subgroups for active travel interventions.

Factors associated with smoke-free homes in NSW: results from the 1998 NSW Health Survey.

Objective : To examine the socio‐demographic characteristics associated with smoke‐free homes (SFHs) in NSW and specify high‐risk groups with a low prevalence of household smoking restrictions.

Temporal trends in non-occupational sedentary behaviours from Australian Time Use Surveys 1992, 1997 and 2006

BackgroundCurrent epidemiological data highlight the potential detrimental associations between sedentary behaviours and health outcomes, yet little is known about temporal trends in adult sedentary time. This study used time use data to examine population trends in sedentary behaviours in non-occupational domains and more specifically during leisure time.MethodsWe conducted secondary analysis of population representative data from the Australian Time Use Surveys 1992, 1997 and 2006 involving respondents aged 20 years and over with completed time use diaries for two days. Weighted samples for each survey year were: n = 5851 (1992), n = 6419 (1997) and n = 5505 (2006). We recoded all primary activities by domain (sleep, occupational, transport, leisure, household, education) and intensity (sedentary, light, moderate). Adjusted multiple linear regressions tested for differences in time spent in non-occupational sedentary behaviours in 1992 and 1997 with 2006 as the reference year.ResultsTotal non-occupational sedentary time was slightly lower in 1997 than in 2006 (mean = 894 min/2d and 906 min/2d, respectively; B = −11.2; 95%CI: -21.5, -0.9). Compared with 2006, less time was spent in 1997 in sedentary transport (B-6.7; 95%CI: -10.4, -3.0) and sedentary education (B = −6.3; 95%CI: -10.5, -2.2) while household and leisure sedentary time remained stable. Time engaged in different types of leisure-time sedentary activities changed between 1997 and 2006: leisure-time computer use increased (B = −26.7; 95%CI: -29.5, -23.8), while other leisure-time sedentary behaviours (e.g., reading, listening to music, hobbies and crafts) showed small concurrent reductions. In 1992, leisure screen time was lower than in 2006: TV-viewing (B = −24.2; 95%CI: -31.2, -17.2), computer use (B = −35.3; 95%CI: -37.7, -32.8). In 2006, 90 % of leisure time was spent sedentary, of which 53 % was screen time.ConclusionsNon-occupational sedentary time has increased slightly from 1997 to 2006 in the Australian adult population. This seems to be the result of small increases in sedentary transport and education time while sedentary household and leisure time were stable over this time period. However, almost all leisure time is spent sedentary and the composition of sedentary leisure time changed between 1992 and 2006 towards a larger proportion being screen-based activities. This could be an important observation for public health, as most of the evidence on the detrimental effects of sedentary behaviour is around watching television and health.