Big World
Impaired mental rotation performance in overweight children
Petra Jansen et al.
Appetite, forthcoming
Abstract:
Overweight children seem to have cognitive impairment. Since there is a relationship between motor and visual-spatial ability and because of the reduced motor abilities of overweight children we assumed that these children might show an impaired mental rotation performance. Sixteen overweight children (10 years of age) and 16 control children (10 years of age) were matched by age, gender, and socio-economic status. Each participant completed a general intelligence test, a motor test, and a chronometric mental rotation test. The results show differences in both motor ability and mental rotation accuracy. Overweight children made more errors when the rotation task was difficult compared to normal weight children. This study gives a clue to overweight children's problems in spatial cognitive tasks.
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Expanding Exposure: Can Increasing the Daily Duration of Head Start Reduce Childhood Obesity?
David Frisvold & Julie Lumeng
Journal of Human Resources, Spring 2011, Pages 373-402
Abstract:
Coinciding with the work requirements of welfare reform in the mid-1990s, the early childhood education program, Head Start, significantly expanded to increase the availability of full-day classes. Using unique administrative data, we examine the effect of full-day compared to half-day attendance on childhood obesity. This effect is identified from changes in obesity over time and from the elimination of a state-provided full-day expansion grant that decreased the supply of full-day classes. Our results suggest that full-day Head Start attendance significantly reduces the proportion of obese children at the end of the academic year.
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Margaret Campbell & Gina Mohr
Journal of Consumer Research, forthcoming
Abstract:
This research investigates the effect of activation of a negative stereotype on behaviors that are perceived to increase the chance of becoming a member of the stereotyped group. Activation of a negative stereotype (the overweight stereotype) is shown to lead to stereotype-consistent goal commitment (low health goal commitment), which partially explains increases in stereotype-conducive behavior (eating indulgent foods). Two theoretically relevant moderators are proposed and supported. Increased accessibility of the countervailing health goal and increased accessibility of the link between the behavior and membership in the stereotyped group both limit the effect of stereotype activation on stereotype-conducive behavior. Five experiments support the facilitative effect of stereotype activation on stereotype-conducive behavior, the role of goal commitment, and both moderators.
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Patricia Anderson, Kristin Butcher & Diane Whitmore Schanzenbach
NBER Working Paper, March 2011
Abstract:
This paper investigates how accountability pressures under No Child Left Behind (NCLB) may affect children's rate of overweight. Schools facing increased pressures to produce academic outcomes may reallocate their efforts in ways that have unintended consequences for children's health. For example, schools may cut back on recess and physical education in favor of increasing time on tested subjects. To examine the impact of school accountability programs, we create a unique panel data set of schools in Arkansas that allows us to test the impact of NCLB rules on students' weight outcomes. Our main approach is to consider schools to be facing increased pressures if they are on the margin of passing - that is, if any subgroup at the school has a passing rate that is close to the AYP passing threshold, where we define close as being 5 percentage points above or below the threshold. We find evidence of small effects of accountability pressures on the percent of students at a school that are overweight. A follow-up survey of school principals points to reductions in physical activity and worsening of the food environment as potential mechanisms.
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The Impact of Stand-Biased Desks in Classrooms on Calorie Expenditure in Children
Mark Benden, Jamilia Blake, Monica Wendel & J. Huber American
Journal of Public Health, forthcoming
Abstract:
Childhood obesity is a public health concern with significant health and economic impacts. We conducted a prospective experimental study in 4 classrooms in central Texas to determine the effect of desks that encourage standing rather than sitting on caloric expenditure in children. Students were monitored with calorie expenditure-measuring arm-bands worn for 10 days in the fall and spring. The treatment group experienced significant increases in calorie expenditure over the control group, a finding that has implications for policy and practice.
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Why healthy eating is bad for young people's health: Identity, belonging and food
Martine Stead et al.
Social Science & Medicine, forthcoming
Abstract:
Research into young people and healthy eating has focussed on identifying the ‘barriers' to healthy eating and on developing interventions to address them. However, it has tended to neglect the emotional, social and symbolic aspects of food for young people, and the roles food might play in adolescence. This paper explores these issues, reporting findings from a qualitative study which explored the meanings and values young people attached to food choices, particularly in school and peer contexts. As part of a larger study into young people's relationships with food brands, 12 focus groups were conducted with young people aged 13-15 in the north east of England. The focus groups found that young people used food choices to help construct a desired image, as a means of judging others, and to signal their conformity with acceptable friendship and peer norms. Importantly, the findings suggested that the social and symbolic meanings associated with healthy eating conflicted with processes and values which are of crucial importance in adolescence, such as self-image and fitting in with the peer group. In other words, it was emotionally and socially risky to be seen to be interested in healthy eating. Interventions need not only to make healthy eating easier and more available, but also to address young people's emotional needs for identity and belonging.
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Gareth Hollands, Andrew Prestwich & Theresa Marteau
Health Psychology, March 2011, Pages 195-203
Objective: To examine the effect of communicating images of energy-dense snack foods paired with aversive images of the potential health consequences of unhealthy eating, on implicit and explicit attitudes and food choice behavior.
Design: Participants were randomly allocated to either an evaluative conditioning (EC) procedure that paired images of snack foods with images of potential adverse health consequences or a control condition that featured images of snack foods alone.
Main Outcome Measures: Implicit attitudes were assessed pre- and post-intervention. Explicit attitudes and food choice behavior were assessed post-intervention.
Results: The conditioning intervention made implicit attitudes toward energy-dense snacks more negative, with this effect greatest in those with relatively more favorable implicit attitudes toward these snacks at baseline. Participants in the conditioning intervention were more likely to choose fruit rather than snacks in a behavioral choice task, a relationship mediated by changes in implicit attitudes.
Conclusion: Presenting aversive images of potential health consequences with those of specific foodstuffs can change implicit attitudes, which impacts on subsequent food choice behavior.
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Guiltless Gluttony: The Asymmetric Effect of Size Labels on Size Perceptions and Consumption
Nİlüfer Aydinoğlu & Aradhna Krishna
Journal of Consumer Research, April 2011, Pages 1095-1112
Abstract:
Size labels adopted by food vendors can have a major impact on size judgments and consumption. In forming size judgments, consumers integrate the actual size information from the stimuli with the semantic cue from the size label. Size labels influence not only size perception and actual consumption, they also affect perceived consumption. Size labels can also result in relative perceived size reversals, so that consumers deem a smaller package to be bigger than a larger one. Further, consumers are more likely to believe a label that professes an item to be smaller (vs. larger) in the size range associated with that item. This asymmetric effect of size labels can result in larger consumption without the consumer even being aware of it ("guiltless gluttony").
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Desiree Wilks et al.
PLoS ONE, February 2011, e17205
Background: Studies investigating the prevention of weight gain differ considerably in design and quality, which impedes pooling them in conventional meta-analyses, the basis for evidence-based policy making. This study is aimed at quantifying the prospective association between measured physical activity and fat mass in children, using a meta-analysis method that allows inclusion of heterogeneous studies by adjusting for differences through eliciting and incorporating expert opinion.
Methods: Studies on prevention of weight gain using objectively measured exposure and outcome were eligible; they were adopted from a recently published systematic review. Differences in study quality and design were considered as internal and external biases and captured in checklists. Study results were converted to correlation coefficients and biases were considered either additive or proportional on this scale. The extent and uncertainty of biases in each study were elicited in a formal process by six quantitatively-trained assessors and five subject-matter specialists. Biases for each study were combined across assessors using median pooling. Results were combined across studies by random-effects meta-analysis.
Results: The combined correlation of the unadjusted results from the six studies was -0.04 (95%CI: -0.22, 0.14) with considerable heterogeneity (I2 = 78%), which makes it difficult to interpret the result. After bias-adjustment the pooled correlation was -0.01 (95%CI: -0.18, 0.16) with apparent study compatibility (I2 = 0%).
Conclusion: By using this method the prospective association between physical activity and fat mass could be quantitatively synthesized; the result suggests no association. Objectively measured physical activity may not be the key determinant of unhealthy weight gain in children.
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Time Spent Eating and Its Implications for Americans' Energy Balance
Cathleen Zick & Robert Stevens
Social Indicators Research, April 2011, Pages 267-273
Abstract:
The upward trend in Americans' weight has precipitated research aimed at identifying its underlying causes. In this paper we examine trends in Americans' time spent eating in an attempt to gain a better understanding of Americans' changing eating habits and their predictors. Data used in the analyses come from four national time use surveys conducted between 1975 and 2007. We find that Americans' total eating time has risen over the past 30 years largely because of increases in secondary eating time. Multivariate analyses reveal that shifts over time in wage rates, food prices, household income, and racial/ethnic composition may be contributing to Americans' changing eating patterns.
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Habit Formation and Demand for Sugar-Sweetened Beverages
Chen Zhen et al.
American Journal of Agricultural Economics, January 2011, Pages 175-193
Abstract:
Using scanner data, we estimated demand for nine nonalcoholic beverages under habit formation. We found strong evidence for habit formation. Although demand for sugar-sweetened beverages by low-income households is less elastic to own-price changes compared with high-income households, there is evidence that high-income households consider beverages to be more substitutable than low-income households do. A half-cent per ounce tax on store-purchased sugar-sweetened beverages will result in a moderate reduction in consumption of sugar-sweetened beverages for both income strata. Because of habit formation, long-run national tax revenue from a sugar-sweetened beverage tax is about 15 to 20% lower than short-run revenue.
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Monika Krzyżanowska & Nicholas Mascie-Taylor
Journal of Biosocial Science, forthcoming
Abstract:
Using a sample of 2090 father and son pairs, the extent of intra- and inter-generational social mobility (migration between social classes) was examined over a 42-year period in a British cohort in relation to height, weight and body mass index (BMI). The mean height difference between the highest and lowest social class decreased from about 4 cm in the fathers' generation to about 3 cm in the sons' generation, indicating a decline in heterogeneity in height between classes. For fathers downward intra-generational social mobility ranged between 11% and 18% while between 16% and 26% were upwardly mobile; for sons 15% were downwardly mobile and 21% upwardly mobile. On average downwardly mobile fathers were shorter by between 0.1 cm and 0.7 cm while upwardly mobile fathers were taller by, on average, 0.6 cm to 1.7 cm. For sons, the downwardly mobile were on average 0.7 cm shorter and the upwardly mobile 0.8 cm taller. For weight and BMI there were no consistent relationships with intra-generational mobility in either the fathers' or sons' generations. Inter-generationally, between 18% and 19% of sons were downwardly mobile and between 39% and 40% were upwardly mobile; the downwardly mobile were shorter by about 0.9 cm and the upwardly taller by between 0.6 cm and 1.2 cm. Sons with higher BMI were more likely to be inter-generationally downwardly mobile.
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Haslyn Hunte
American Journal of Epidemiology, forthcoming
Abstract:
The relation between perceived interpersonal experiences of discrimination and measures of obesity is of great interest to many. This study examined the relation between changes in waist circumference and changes in perceived interpersonal everyday discrimination using the 1995-2004 Midlife Development in the United States cohort study (N = 1,452). After controlling for potential confounding variables that assessed behavioral and sociodemographic characteristics, sex-stratified ordinary least squares regression analyses suggested that the waist circumference of adult males who reported consistently high levels of interpersonal everyday discrimination increased 2.39 cm more than that of adult males who consistently reported low levels of interpersonal everyday discrimination (P < 0.05). Similarly, the waist circumference of adult females who reported an increase in interpersonal everyday discrimination increased 1.88 cm more than that of adult females who reported consistently low levels of interpersonal everyday discrimination (P < 0.05). These findings suggest that perceived interpersonal everyday discrimination may be associated with an increase in waist circumference over time among adults in the United States.
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Adam Fletcher, Chris Bonell & Annik Sorhaindo
Journal of Epidemiology & Community Health, forthcoming
Background: This review synthesises evidence regarding associations between young people's social networks and their eating behaviours/bodyweight, and also explores how these vary according to the setting and sample characteristics.
Methods: A systematic review of cross-sectional and longitudinal observational studies examining the association between measures of young people's social networks based on sociometric data and eating behaviours (including calorific intake) and/or bodyweight.
Results: There is consistent evidence that school friends are significantly similar in terms of their body mass index, and friends with the highest body mass index appear to be most similar. Overweight youth are also less likely to be popular and more likely to be socially isolated at school. Frequency of fast food consumption has also been found to cluster within groups of boys, as have body image concerns, dieting and eating disorders among girls.
Conclusion: School friendships may be critical in shaping young people's eating behaviours and bodyweight and/or vice versa, and suggests the potential of social-network-based health promotion interventions in schools. Further longitudinal research is needed to examine the processes via which this clustering occurs, how it varies according to school context, and the effects of non-school networks.
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Juan Zhang et al.
Journal of Adolescent Health, April 2011, Pages 366-372
Purpose: The study compared differences in overweight prevalence, weight perception, and weight-related practices among high school students in five large Chinese and U.S. cities, and informed interventions for childhood obesity in China and the U.S.
Methods: The data used was collected in 2003 from a representative sample of high school students in Hong Kong, Macau, Taipei, New York and Los Angeles.
Results: The prevalence of overweight high school students in New York City and Los Angeles was about twice as high as in Hong Kong, Macau, and Taipei; however, the proportion of Chinese students perceiving themselves to be overweight was 15% higher than their U.S. counterparts. Independent of actual weight status, perceived overweight was significantly associated with weight control practices (p < .05). U.S. students showed higher levels of moderate and vigorous physical activity, but more hours of watching television than their Chinese counterparts.
Conclusion: The continuing pandemic of overweight among youth fosters weight dissatisfaction, which may increase unhealthy weight control practices. Interventions should be designed to prevent overweight without precipitating unhealthy weight control practices by emphasizing an increase in physical activity and a reduction in time watching television.
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Maternal unemployment and childhood overweight: Is there a relationship?
Leslie Stewart, Yujia Liu & Eunice Rodriguez
Journal of Epidemiology & Community Health, forthcoming
Background: Previous studies have shown a positive association between maternal work hours and childhood overweight. However, it is unclear what role job instability plays in this relationship; therefore, this study examined whether children whose mothers experienced unemployment were more likely to have greater increases in body mass index (BMI) as compared with children whose mothers were stably employed. The effects of unemployment benefits, welfare and number of hours worked were also explored.
Methods: A multiple regression analysis was used to analyse changes in BMI over a 4-year period using the National Longitudinal Survey of Youth. In all, 4890 US children, aged 2-16 at baseline, were included in the analysis.
Results: As compared with children of mothers who were employed full-time and did not receive welfare, children of mothers who experienced unemployment and received unemployment benefits were not more likely to have significantly different changes in BMI. Yet children of mothers who experienced unemployment and did not receive unemployment benefits were significantly more likely to have greater increases in BMI. These results were also shown in models which controlled for height. This supports the conclusion that adiposity changes, and not simply growth-rate differences, account for the different BMI changes between groups.
Conclusion: Aspects of maternal employment other than number of work hours are associated with child BMI, including unemployment events and what type of support a mother receives during the time of unemployment. This has implications for policies that relate to benefits for mothers who lose their jobs.
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A Demographic Profile of Obesity in the Adult and Veteran US Populations in 2008
Johnelle Sparks & Mary Bollinger
Population Research and Policy Review, April 2011, Pages 211-233
Abstract:
Obesity is increasing in the US population and seems to be disproportionately burdening disadvantaged groups. Veterans using the Veterans Healthcare System (VHS) tend to be more disadvantaged socioeconomically than the general population and in poorer health. It is important to understand how the veteran population differs from or is similar to the general population and whether the VHS is able to mediate obesity risk among veterans. This research assesses the sociodemographic, behavioral, and health risk factors for obesity in the US adult and veteran populations in 2008. We use data from the 2008 Behavioral Risk Factor Surveillance System (BRFSS) to empirically assess predictors of obesity risk. We find that women have lower odds of obesity than men once controls for sociodemographic, behavioral, and health conditions are included in our models. We also observe a veteran obesity disadvantage in the full adult sample when conducting bivariate tests, but no significant association with the odds of obesity in the logistic regression models among veterans and non-veterans. Gender specific models indicate that male veterans have increased odds of obesity compared to non-veterans, but no difference in obesity risks among veterans and non-veterans are noted for women, controlling for all variables. Further, we find no significant differences in the odds of obesity of veterans using VHS for all, some, or none of their health care needs; further no significant gender differences in obesity risk were observed among VHS usages and non-users. Based on the strong, positive association between the number of chronic health conditions and the odds of obesity, we suggest that health policy should focus efforts on weight management counseling for obese patients that have obesity related co-morbidities, and more targeted attention to male veterans would help to address the high level of obesity in this vulnerable population group.
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J.C. Eisenmann et al.
Obesity Reviews, forthcoming
Abstract:
In the USA, several nutrition-related issues confront the normal growth, maturation and development of children and adolescents including obesity and food insecurity. The purpose of this paper is to provide a review of the concept of food insecurity and a summary of studies that have examined the association between food insecurity and overweight/obesity in children and adolescents. Besides the initial case report, we review 21 studies (16 cross-sectional and five prospective studies) that have been published on this topic as of December 2009. As there is limited literature in this area, we review studies that sample children and adolescents in the USA. The results are mixed with positive, negative and null associations. The reasons for the mixed results are difficult to disentangle. Among earlier studies, small samples hampered definitive conclusions. More recent studies with larger samples have overcome these limitations and tend to find no associations between these constructs. Nonetheless, all of the studies to date have shown that food insecurity and overweight co-exist - that is, even though there may not be statistically significant differences in overweight between food-insecure and food-secure children, the prevalence of overweight remains relatively high in food-insecure children.
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Rachel Tolbert Kimbro, Jeanne Brooks-Gunn & Sara McLanahan
Social Science & Medicine, March 2011, Pages 668-676
Abstract:
Although research consistently demonstrates a link between residential context and physical activity for adults and adolescents, less is known about young children's physical activity. Using data from the U.S. Fragile Families and Child Wellbeing Study (N = 1822, 51% male), we explored whether outdoor play and television watching were associated with children's body mass indexes (BMIs) at age five using OLS regression models, controlling for a wide array of potential confounders, including maternal BMI. We also tested whether subjective and objective neighborhood measures - socioeconomic status (from U.S. Census tract data), type of dwelling, perceived collective efficacy, and interviewer-assessed physical disorder of the immediate environment outside the home - were associated with children's activities, using negative binomial regression models. Overall, 19% of the sample were overweight (between the 85th and 95th percentiles), and 16% were obese (≥95th percentile). Hours of outdoor play were negatively associated with BMI, and hours of television were positively associated with BMI. Moreover, a ratio of outdoor play to television time was a significant predictor of BMI. Higher maternal perceptions of neighborhood collective efficacy were associated with more hours of outdoor play, fewer hours of television viewing, and more trips to a park or playground. In addition, we found that neighborhood physical disorder was associated with both more outdoor play and more television watching. Finally, contrary to expectations, we found that children living in public housing had significantly more hours of outdoor play and watched more television, than other children. We hypothesize that poorer children may have more unstructured time, which they fill with television time but also with outdoor play time; and that children in public housing may be likely to have access to play areas on the grounds of their housing facilities.
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Obesity and short sleep: Unlikely bedfellows?
J. Horne
Obesity Reviews, forthcoming
Abstract:
The link between habitual short sleep and obesity is critically examined from a sleep perspective. Sleep estimates are confounded by ‘time in bed', naps; the normal distribution of sleep duration. Wide categorizations of ‘short sleep', with claims that <7 h sleep is associated with obesity and morbidity, stem from generalizations from 5 h sleepers (<8% of adults) and acute restriction studies involving unendurable sleepiness. Statistically significant epidemiological findings are of questionable clinical concern, even for 5 h sleepers, as any weight gains accumulate slowly over years; easily redressed by e.g. short exercise exposures, contrasting with huge accumulations of ‘lost' sleep. Little evidence supports ‘more sleep', alone, as an effective treatment for obesity. Impaired sleep quality and quantity are surrogates for many physical and psychological disorders, as can be obesity. Advocating more sleep, in these respects, could invoke unwarranted use of sleep aids including hypnotics. Inadequate sleep in obese children is usually symptomatic of problems not overcome by increasing sleep alone. Interestingly, neuropeptides regulating interactions between sleep, locomotion and energy balance in normal weight individuals, are an avenue for investigation in some obese short sleepers. The real danger of inadequate sleep lies with excessive daytime sleepiness, not obesity.
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Irish exceptionalism? Local food environments and dietary quality
Richard Layte et al.
Journal of Epidemiology & Community Health, forthcoming
Objective: To explore whether distance to and density of food outlets within the local area have an impact on individual dietary quality, controlling for the socioeconomic characteristics of individuals and their households.
Methods: An analysis of the Survey of Lifestyle, Attitudes and Nutrition in Ireland (SLÁN), a two-stage clustered sample of 10 364 individuals aged 18+ from the Republic of Ireland. Socioeconomic status was measured using net household income and highest level of education. Diet was assessed via a food frequency questionnaire and the results scored in terms of cardiovascular risk. Food availability was measured in terms of distance to (Euclidean and network) and density of different types of food outlets. Dietary quality was decomposed using fixed effects regression models.
Results: There is a pronounced gradient in distances to nearest food store and quality of diet by socioeconomic status. Controlling for individual and household socioeconomic status and demographic characteristics, individuals who live closer to a larger food outlet or who live in an area with a higher density of larger food outlets have a significantly better diet in terms of cardiovascular risk.
Conclusions: Studies outside of North America have failed to find that the physical availability of food plays a significant role in socioeconomic gradients in diet and nutrition. This study suggests that food availability in the Republic of Ireland plays a small but statistically significant role in influencing the diets of individuals and communities and, as such, may also influence socioeconomic inequalities in health.
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The number of years lived with obesity and the risk of all-cause and cause-specific mortality
Asnawi Abdullah et al.
International Journal of Epidemiology, forthcoming
Background: The role of the duration of obesity as an independent risk factor for mortality has not been investigated. The aim of this study was to analyse the association between the duration of obesity and the risk of mortality.
Methods: A total of 5036 participants (aged 28-62 years) of the Framingham Cohort Study were followed up every 2 years from 1948 for up to 48 years. The association between obesity duration and all-cause and cause-specific mortality was analysed using time-dependent Cox models adjusted for body mass index. The role of biological intermediates and chronic diseases was also explored.
Results: The adjusted hazard ratio (HR) for mortality increased as the number of years lived with obesity increased. For those who were obese for 1-4.9, 5-14.9, 15-24.9 and ≥25 years of the study follow-up period, adjusted HRs for all-cause mortality were 1.51 [95% confidence interval (CI) 1.27-1.79], 1.94 (95% CI 1.71-2.20), 2.25 (95% CI 1.89-2.67) and 2.52 (95% CI 2.08-3.06), respectively, compared with those who were never obese. A dose-response relation between years of duration of obesity was also clear for all-cause, cardiovascular, cancer and other-cause mortality. For every additional 2 years of obesity, the HRs for all-cause, cardiovascular disease, cancer and other-cause mortality were 1.06 (95% CI 1.05-1.07), 1.07 (95% CI 1.05-1.08), 1.03 (95% CI 1.01-1.05) and 1.07 (95% CI 1.05-1.11), respectively.
Conclusions: The number of years lived with obesity is directly associated with the risk of mortality. This needs to be taken into account when estimating its burden on mortality.