Catrine Tudor-Locke

Changing the way we work: elevating energy expenditure with workstation alternatives

Emerging evidence supports the feasibility of raising daily energy expenditure (EE) by replacing office work-related sedentary behavior with low-intensity non-exercise physical activity (PA) via workstation alternatives to the traditional office chair and desktop computer-based combinations. The purpose of this review article is to introduce a simple taxonomy to facilitate classification and study of workstation alternatives, catalog the diversity of research undertaken to date related to energy balance, and present and summarize the gaps and opportunities for a research agenda for workstation alternatives moving forward. A PubMed search elicited 57 English language articles published since 2000; additional articles were identified by reviewing reference sections and contacting authors. Selection criteria ultimately focused on use of workstation alternatives during simulated or real work tasks. The EE of sitting on a stability ball or using sit–stand/standing desks is comparable to the traditional seated condition (≅1.2 kcal min−1). The treadmill and pedal desks (active workstation alternatives) offer the greatest promise in terms of EE (≅2–4 kcal min−1). Sitting on a stability ball or using sit–stand/standing desks does not impair task performance relative to the traditional seated condition. Some evidence of typing impairment is inconsistently reported with active workstation alternatives; the finer motor skills required for mouse-related tasks may be more affected. Little is known about learning or adaptation with practice. Users are generally accepting of workstation alternatives; however, there is evidence of less than optimal use. Active workstations (that is, treadmill desks and pedal desks) in particular represent a potential strategy for mitigating the diminished EE inherent to contemporary office-based workplaces, but only if they are scalable. The science supporting active workstations is young and heterogeneous; however, this means that there are many knowledge gaps and opportunities for research, including those focused on implementation issues related to optimizing both employers’ and workers’ uptake.

Comparison of Lifecorder EX and ActiGraph accelerometers under free-living conditions

The Kenz Lifecorder EX (LC; Suzuken Co. Ltd., Nagoya, Japan) offers several potentially attractive features for researchers and practitioners compared with accelerometers such as the ActiGraph (AG; ActiGraph Health Services, Fort Walton Beach, Fla.). The purposes of this study were (i) to evaluate the LCs intra-model reliability for outputs of steps and time spent in moderate, vigorous, and combined moderate plus vigorous physical activity (MVPA) and (ii) to compare the same LC vs. AG outputs under free-living conditions. Ten participants (n = 5 males) wore two LCs and one AG accelerometer during all waking hours on one day. Steps were outputted from all monitors. Additionally, two LC and five AG intensity derivations were used to assess time in moderate activity, vigorous activity, and MVPA. Intra-class correlations (ICC) were used to assess intra-model reliability between LCs. Paired t tests and repeated-measures analyses of variance (ANOVAs) were used to assess differences between the two LCs and LC vs. AG outputs of steps and time in various intensity derivations where appropriate. No significant differences were detected between outputs from different LCs (ICCs ranged from 0.95 to 0.99). The LC detected significantly fewer steps vs. AG (mean difference = 1516 steps). All LC vs. AG vigorous-intensity derivations provided similar outputs. Additionally, comparable estimates of MVPA time were produced by one of two LC intensity derivations compared with specific AG cut points established each by Freedson, Hendelman (walking), and Matthews. LC displayed high inter-model reliability. Although the LC detected fewer steps than the AG, the LC detects time in specific PA intensity categories comparable to several existing AG cut points.

Relationships between Parental Education and Overweight with Childhood Overweight and Physical Activity in 9-11 Year Old Children: Results from a 12-Country Study.

Background Globally, the high prevalence of overweight and low levels of physical activity among children has serious implications for morbidity and premature mortality in adulthood. Various parental factors are associated with childhood overweight and physical activity. The objective of this paper was to investigate relationships between parental education or overweight, and (i) child overweight, (ii) child physical activity, and (iii) explore household coexistence of overweight, in a large international sample. Methods Data were collected from 4752 children (9–11 years) as part of the International Study of Childhood Obesity, Lifestyle and the Environment in 12 countries around the world. Physical activity of participating children was assessed by accelerometry, and body weight directly measured. Questionnaires were used to collect parents’ education level, weight, and height. Results Maternal and paternal overweight were positively associated with child overweight. Higher household coexistence of parent-child overweight was observed among overweight children compared to the total sample. There was a positive relationship between maternal education and child overweight in Colombia 1.90 (1.23–2.94) [odds ratio (confidence interval)] and Kenya 4.80 (2.21–10.43), and a negative relationship between paternal education and child overweight in Brazil 0.55 (0.33–0.92) and the USA 0.54 (0.33–0.88). Maternal education was negatively associated with children meeting physical activity guidelines in Colombia 0.53 (0.33–0.85), Kenya 0.35 (0.19–0.63), and Portugal 0.54 (0.31–0.96). Conclusions Results are aligned with previous studies showing positive associations between parental and child overweight in all countries, and positive relationships between parental education and child overweight or negative associations between parental education and child physical activity in lower economic status countries. Relationships between maternal and paternal education and child weight status and physical activity appear to be related to the developmental stage of different countries. Given these varied relationships, it is crucial to further explore familial factors when investigating child overweight and physical activity.

Compositional data analysis for physical activity, sedentary time and sleep research

The health effects of daily activity behaviours (physical activity, sedentary time and sleep) are widely studied. While previous research has largely examined activity behaviours in isolation, recent studies have adjusted for multiple behaviours. However, the inclusion of all activity behaviours in traditional multivariate analyses has not been possible due to the perfect multicollinearity of 24-h time budget data. The ensuing lack of adjustment for known effects on the outcome undermines the validity of study findings. We describe a statistical approach that enables the inclusion of all daily activity behaviours, based on the principles of compositional data analysis. Using data from the International Study of Childhood Obesity, Lifestyle and the Environment, we demonstrate the application of compositional multiple linear regression to estimate adiposity from children’s daily activity behaviours expressed as isometric log-ratio coordinates. We present a novel method for predicting change in a continuous outcome based on relative changes within a composition, and for calculating associated confidence intervals to allow for statistical inference. The compositional data analysis presented overcomes the lack of adjustment that has plagued traditional statistical methods in the field, and provides robust and reliable insights into the health effects of daily activity behaviours.

Birth weight and childhood obesity: a 12-country study

OBJECTIVES Few studies have investigated the association between the full range of birth weight and the risk of childhood obesity in high-, middle- and low-income countries. The aim of the present study is to assess the association between different levels of birth weight and the risk of obesity among children aged 9-11 years in 12 countries. METHODS A multinational, cross-sectional study of 5141 children aged 9-11 years was conducted in 12 countries. Height and weight were obtained using standardized methods. Time spent in moderate-to-vigorous physical activity (MVPA), sedentary and sleeping were objectively measured using 24-h, waist-worn accelerometer (Actigraph GT3X+) monitored for 7 days. Birth weight and other factors (regions, parental education, maternal history of gestational diabetes, children age, gender, breast feeding, gestational age, unhealthy diet scores and healthy diet scores) were collected by parental and childrens questionnaires. Multilevel modeling was used to account for the nested nature of the data. RESULTS The overall prevalence of obesity (BMI z-score>+2 s.d.) was 15.4% for boys and 10.0% for girls. There was a positive association between birth weight and BMI z-scores. The multivariable-adjusted odds ratios (ORs) of childhood obesity were significantly higher among children whose birth weights were 3500-3999 g (OR 1.45; 95% confidence interval (CI): 1.10-1.92), and >4000 g (OR 2.08; 95% CI: 1.47-2.93), compared with the reference group (2500-2999 g). The positive association between birth weight and the odds of childhood obesity was seen in girls, whereas a U-shaped association appeared in boys. CONCLUSIONS High levels of birth weight, defined as birth weight ⩾3500 g, were associated with increased odds of obesity among 9-11-year-old children in 12 countries. However, sex differences in the association between birth weight and the risk of obesity need to be considered when planning interventions to reduce childhood obesity.

Health-related quality of life and lifestyle behavior clusters in school-aged children from 12 countries

Objective To evaluate the relationship between childrens lifestyles and health‐related quality of life and to explore whether this relationship varies among children from different world regions. Study design This study used cross‐sectional data from the International Study of Childhood Obesity, Lifestyle and the Environment. Children (9‐11 years) were recruited from sites in 12 nations (n = 5759). Clustering input variables were 24‐hour accelerometry and self‐reported diet and screen time. Health‐related quality of life was self‐reported with KIDSCREEN‐10. Cluster analyses (using compositional analysis techniques) were performed on a site‐wise basis. Lifestyle behavior cluster characteristics were compared between sites. The relationship between cluster membership and health‐related quality of life was assessed with the use of linear models. Results Lifestyle behavior clusters were similar across the 12 sites, with clusters commonly characterized by (1) high physical activity (actives); (2) high sedentary behavior (sitters); (3) high screen time/unhealthy eating pattern (junk‐food screenies); and (4) low screen time/healthy eating pattern and moderate physical activity/sedentary behavior (all‐rounders). Health‐related quality of life was greatest in the all‐rounders cluster. Conclusions Children from different world regions clustered into groups of similar lifestyle behaviors. Cluster membership was related to differing health‐related quality of life, with children from the all‐rounders cluster consistently reporting greatest health‐related quality of life at sites around the world. Findings support the importance of a healthy combination of lifestyle behaviors in childhood: low screen time, healthy eating pattern, and balanced daily activity behaviors (physical activity and sedentary behavior). Trial registration ClinicalTrials.gov: NCT01722500.

The reliability and validity of a short food frequency questionnaire among 9-11-year olds: a multinational study on three middle-income and high-income countries.

OBJECTIVE The main aim of this study was to assess the reliability and validity of a food frequency questionnaire with 23 food groups (I-FFQ) among a sample of 9-11-year-old children from three different countries that differ on economical development and income distribution, and to assess differences between country sites. Furthermore, we assessed factors associated with I-FFQs performance. METHODS This was an ancillary study of the International Study of Childhood Obesity, Lifestyle and the Environment. Reliability (n=321) and validity (n=282) components of this study had the same participants. Participation rates were 95% and 70%, respectively. Participants completed two I-FFQs with a mean interval of 4.9 weeks to assess reliability. A 3-day pre-coded food diary (PFD) was used as the reference method in the validity analyses. Wilcoxon signed-rank tests, intraclass correlation coefficients and cross-classifications were used to assess the reliability of I-FFQ. Spearman correlation coefficients, percentage difference and cross-classifications were used to assess the validity of I-FFQ. A logistic regression model was used to assess the relation of selected variables with the estimate of validity. Analyses based on information in the PFDs were performed to assess how participants interpreted food groups. RESULTS Reliability correlation coefficients ranged from 0.37 to 0.78 and gross misclassification for all food groups was <5%. Validity correlation coefficients were below 0.5 for 22/23 food groups, and they differed among country sites. For validity, gross misclassification was <5% for 22/23 food groups. Over- or underestimation did not appear for 19/23 food groups. Logistic regression showed that country of participation and parental education were associated (P⩽0.05) with the validity of I-FFQ. Analyses of childrens interpretation of food groups suggested that the meaning of most food groups was understood by the children. CONCLUSION I-FFQ is a moderately reliable method and its validity ranged from low to moderate, depending on food group and country site.

The epidemiological transition and the global childhood obesity epidemic.

OBJECTIVES Childhood obesity is now recognized as a global public health issue. Social patterning of obesity, consistent with the theory of epidemiologic transition, has not been well described in children, and the limited research has focused on developed settings. The aim of this study was to describe the relationship between childhood obesity and household income using objective measures of adiposity and to explore how this relationship differs across levels of country human development. METHODS The International Study of Childhood Obesity, Lifestyle and the Environment (ISCOLE) was a multi-national cross-sectional study conducted in 12 urban/suburban study sites that represented all inhabited continents and wide ranges of development. ISCOLE collected objectively measured height, body mass and percentage body fat in 7341 10-year-old children. Multi-level random-effects models were used to examine income gradients in several obesity measures. RESULTS The mean age of the children was 10.4 years, and 12.6% were obese, ranging from 5.4% (Finland) to 23.8% (China). For both boys and girls, obesity prevalence, body fat percentage and body mass index (BMI) z-score increased linearly with higher income at lower levels of development (all P for trend ⩽0.0012), but decreased linearly with higher income at higher levels of development (all P for trend ⩽0.0003). Country human development explained 75% of the variation in the country-specific income-obesity relationships (r=-0.87, P=0.0003). CONCLUSIONS Results are consistent with the theory of epidemiologic transition. Global efforts to control obesity must account for socioeconomic factors within a countrys context. Future research should seek to understand global socioeconomic patterns in obesity-related lifestyle behaviors.

Relationship between Soft Drink Consumption and Obesity in 9–11 Years Old Children in a Multi-National Study

The purpose of this study was to determine the association between regular (sugar containing) and diet (artificially sweetened) soft drink consumption and obesity in children from 12 countries ranging in levels of economic and human development. The sample included 6162 children aged 9–11 years. Information on soft drink consumption was obtained using a food frequency questionnaire. Percentage body fat (%BF) was estimated by bio-electrical impedance analysis, body mass index (BMI) z-scores were computed using World Health Organization reference data, and obesity was defined as a BMI > +2 standard deviations (SD). Multi-level models were used to investigate trends in BMI z-scores, %BF and obesity across categories of soft drink consumption. Age, sex, study site, parental education and physical activity were included as covariates. There was a significant linear trend in BMI z-scores across categories of consumption of regular soft drinks in boys (p = 0.049), but not in girls; there were no significant trends in %BF or obesity observed in either boys or girls. There was no significant linear trend across categories of diet soft drink consumption in boys, but there was a graded, positive association in girls for BMI z-score (p = 0.0002) and %BF (p = 0.0001). Further research is required to explore these associations using longitudinal research designs.

Strategic Priorities for Physical Activity Surveillance in the United States.

PURPOSE Develop strategic priorities to guide future physical activity surveillance in the United States. METHODS The Centers for Disease Control and Prevention and the American College of Sports Medicine convened a scientific roundtable of physical activity and measurement experts. Participants summarized the current state of aerobic physical activity surveillance for adults, focusing on practice and research needs in three areas: 1) behavior, 2) human movement, and 3) community supports. Needs and challenges for each area were identified. At the conclusion of the meeting, experts identified one overarching strategy and five strategic priorities to guide future surveillance. RESULTS The identified overarching strategy was to develop a national plan for physical activity surveillance similar to the U.S. National Physical Activity Plan for promotion. The purpose of the plan would be to enhance coordination and collaboration within and between sectors, such as transportation and public health, and to address specific strategic priorities identified at the roundtable. These strategic priorities were used 1) to identify and prioritize physical activity constructs; 2) to assess the psychometric properties of instruments for physical activity surveillance; 3) to provide training and technical assistance for those collecting, analyzing, or interpreting surveillance data; 4) to explore accessing data from alternative sources; and 5) to improve communication, translation, and dissemination about estimates of physical activity from surveillance systems. CONCLUSION This roundtable provided strategic priorities for physical activity surveillance in the United States. A first step is to develop a national plan for physical activity surveillance that would provide an operating framework from which to execute these priorities.