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Monday, December 24, 2012

Second Course


Childcare and Overweight or Obesity over 10 Years of Follow-Up

Marie-Claude Geoffroy et al.
Journal of Pediatrics, forthcoming

Objective: To investigate the predictive association between preschool childcare arrangements and overweight/obesity in childhood.

Study design: Children were enrolled in a prospective birth cohort in Quebec, Canada (n = 1649). Information about childcare obtained via questionnaires to the mothers at ages 1.5, 2.5, 3.5, and 4 years was used to compute a main childcare arrangement exposure variable (center-based/family-based/care by a relative/nanny). Body mass index was derived from measured weights and heights at ages 4, 6, 7, 8, and 10 years and children were classified as overweight/obese versus normal weight. Generalized estimating equations were used to model the effect of main childcare arrangement (center-based/family-based/relative/nanny) (vs parental care) on overweight/obesity adjusting for several potential confounding factors.

Results: Compared with parental care, children who attended a center-based childcare (OR: 1.65, 95% CI: 1.13-2.41) or were cared for by a relative (OR: 1.50; 95% CI: 0.95-2.38, although with greater uncertainty) had higher odds of being overweight/obese in childhood (4-10 years). Analyses of number of hours additionally suggested that each increment of 5 hours spent in either center-based or relative childcare increased the odds of overweight/obesity in the first decade of life by 9%. Associations were not explained by a wide range of confounding factors, including socioeconomic position, breastfeeding, maternal employment, and maternal body mass index.

Conclusion: Overweight/obesity was more frequently observed in children who received non-parental care in center-based settings or care by a relative other than the parent. "Obesogeonic" features of these childcare arrangements should be investigated in future studies.


The Effects of Childhood SNAP Use and Neighborhood Conditions on Adult Body Mass Index

Thomas Vartanian & Linda Houser
Demography, August 2012, Pages 1127-1154

The disproportionate number of individuals who are obese or overweight in the low-income U.S. population has raised interest in the influence of neighborhood conditions and public assistance programs on weight and health. Generally, neighborhood effects and program participation effects have been explored in separate studies. We unite these two areas of inquiry, using the 1968-2005 Panel Study of Income Dynamics (PSID) to examine the long-term effects of childhood Supplemental Nutrition Assistance Program (SNAP) participation, neighborhood conditions, and the interaction of these two, on adult body mass index (BMI). Using sibling fixed-effects models to account for selection bias, we find that relative to children in other low-income families, children in SNAP-recipient households have higher average adult BMI values. However, the effects of childhood SNAP usage are sensitive to both residential neighborhood and age at receipt. For those growing up in advantaged neighborhoods, projected adult BMI is higher for children in SNAP-recipient households than for children in low-income, nonrecipient households. In contrast, for those growing up in less-advantaged areas, adult BMI differences between children in SNAP-recipient and those in low-income, nonrecipient households are small. SNAP usage during preschool years (0 to 4) has no impact on adult BMI scores. However, at later childhood ages, the time elapsed receiving SNAP income increases adult BMI values relative to a condition of low-income nonreceipt.


Fast-Food Restaurant Advertising on Television and Its Influence on Youth Body Composition

Michael Grossman, Erdal Tekin & Roy Wada
NBER Working Paper, December 2012

We examine the effects of fast-food restaurant advertising on television on the body composition of adolescents as measured by percentage body fat (PBF) and to assess the sensitivity of these effects to using conventional measures of youth obesity based on body-mass index (BMI). We merge measures of body composition from bioelectrical-impedance analysis (BIA) and dual-energy x-ray absorptiometry (DXA) from the National Health and Nutrition Examination Survey with individual level data from the National Longitudinal Survey of Youth 1997 and data on local fast-food restaurant advertising on television from Competitive Media Reporting. Exposure to fast-food restaurant advertising on television causes statistically significant increases in PBF in adolescents. These results are consistent with those obtained by using BMI-based measures of obesity. The responsiveness to fast-food advertising is greater for PBF than for BMI. Males are more responsive to advertising than females regardless of the measure. A complete advertising ban on fast-food restaurants on television would reduce BMI by 2 percent and PBF by 3 percent. The elimination of the tax deductibility of food advertising costs would still leave a considerable number of youth exposed to fast-food advertising on television but would still result in non-trivial reductions in obesity.


Neighborhood Street Scale Elements, Sedentary Time and Cardiometabolic Risk Factors in Inactive Ethnic Minority Women

Rebecca Lee, Scherezade Mama & Heather Adamus-Leach
PLoS ONE, December 2012

Background: Cardiometabolic risk factors such as obesity, excess percent body fat, high blood pressure, elevated resting heart rate and sedentary behavior have increased in recent decades due to changes in the environment and lifestyle. Neighborhood micro-environmental, street scale elements may contribute to health above and beyond individual characteristics of residents.

Purpose: To investigate the relationship between neighborhood street scale elements and cardiometabolic risk factors among inactive ethnic minority women.

Method: Women (N = 410) completed measures of BMI, percent body fat, blood pressure, resting heart rate, sedentary behavior and demographics. Trained field assessors completed the Pedestrian Environment Data Scan in participants' neighborhoods. Data were collected from 2006-2008. Multiple regression models were conducted in 2011 to estimate the effect of environmental factors on cardiometabolic risk factors.

Results: Adjusted regression models found an inverse association between sidewalk buffers and blood pressure, between traffic control devices and resting heart rate, and a positive association between presence of pedestrian crossing aids and BMI (ps<.05). Neighborhood attractiveness and safety for walking and cycling were related to more time spent in a motor vehicle (ps<.05).

Conclusions: Findings suggest complex relationships among micro-environmental, street scale elements that may confer important cardiometabolic benefits and risks for residents. Living in the most attractive and safe neighborhoods for physical activity may be associated with longer times spent sitting in the car.


Gender-Specific Effects of Early Nutritional Restriction on Adult Obesity Risk: Evidence From Quasi-Experimental Studies

Whitney Robinson
Obesity, December 2012, Pages 2464-2466

In countries undergoing nutrition transition and historically poor minority groups in wealthy countries, obesity tends to be more common in women than men. A potential contributor to this female excess of obesity is a mismatch between perinatal nutritional restriction and a later calorie-rich environment. Several epidemiologic and quasi-experimental studies support a gender-differential effect of early nutritional deprivation on adult obesity. The quasi-experimental studies are of particular interest because results of quasi-experimental studies are typically less vulnerable to confounding bias than observational studies. Four quasi-experimental studies - exploiting 20th century famines that occurred in Europe, Africa, and Asia - provide evidence that perinatal nutritional restriction followed by relative caloric abundance may increase adult obesity risk to a greater extent in women than men. If the findings are accurate and generalizable to contemporary food environments, they suggest that the female offspring of poor, or otherwise nutritionally restricted, women in rapidly developing and wealthy countries may be at particularly high risk of adult obesity. Research into gender-specific effects of early life nutritional deprivation and its interactions with later environmental exposures may provide insight into global gender differences in obesity prevalence.


Education and obesity at age 40 among American adults

Alison Cohen et al.
Social Science & Medicine, forthcoming

Although many have studied the association between educational attainment and obesity, studies to date have not fully examined prior common causes and possible interactions by race/ethnicity or gender. It is also not clear if the relationship between actual educational attainment and obesity is independent of the role of aspired educational attainment or expected educational attainment. The authors use generalized linear log link models to examine the association between educational attainment at age 25 and obesity (BMI≥30) at age 40 in the USA's National Longitudinal Survey of Youth 1979 cohort, adjusting for demographics, confounders, and mediators. Race/ethnicity but not gender interacted with educational attainment. In a complete case analysis, after adjusting for socioeconomic covariates from childhood, adolescence, and adulthood, among whites only, college graduates were less likely than high school graduates to be obese (RR= 0.69, 95%CI: 0.57, 0.83). The risk ratio remained similar in two sensitivity analyses when the authors adjusted for educational aspirations and educational expectations and analyzed a multiply imputed dataset to address missingness. This more nuanced understanding of the role of education after controlling for a thorough set of confounders and mediators helps advance the study of social determinants of health and risk factors for obesity.


Potential Effect of Physical Activity Based Menu Labels on the Calorie Content of Selected Fast Food Meals

Sunaina Dowray et al.
Appetite, forthcoming

In this study we examined the effect of physical activity based labels on the calorie content of meals selected from a sample fast food menu. Using a web-based survey, participants were randomly assigned to one of four menus which differed only in their labeling schemes (n=802): (1) a menu with no nutritional information, (2) a menu with calorie information, (3) a menu with calorie information and minutes to walk to burn those calories, or (4) a menu with calorie information and miles to walk to burn those calories. There was a significant difference in the mean number of calories ordered based on menu type (p=0.02), with an average of 1020 calories ordered from a menu with no nutritional information, 927 calories, ordered from a menu with only calorie information, 916 calories, ordered from a menu with both calorie information and minutes to walk to burn those calories, and 826 calories, ordered from the menu with calorie information and the number of miles to walk to burn those calories. The menu with calories and the number of miles to walk to burn those calories appeared the most effective in influencing the selection of lower calorie meals (p=0.0007) when compared to the menu with no nutritional information provided). The majority of participants (82%) reported a preference for physical activity based menu labels over labels with calorie information alone and no nutritional information. Whether these labels are effective in real-life scenarios remains to be tested.


History, haldanes and health inequities: Exploring phenotypic changes in body size by generation and income level in the US-born White and Black non-Hispanic populations 1959-1962 to 2005-2008

Nancy Krieger et al.
International Journal of Epidemiology, forthcoming

Background: Most public health literature on trends in population health and health inequities pertains to observed or targeted changes in rates or proportions per year or decade. We explore, in novel analyses, whether additional insight can be gained by using the ‘haldane', a metric developed by evolutionary biologists to measure change in traits in standard deviations per generation, thereby enabling meaningful comparisons across species and time periods.

Methods: We analysed the phenotypic embodied traits of body height, weight and body mass index of US-born White and Black non-Hispanic adults ages 20 to 44 as measured in six large nationally representative population samples spanning from the 1959-1962 National Health Examination Survey I to the 2005-2008 National Health and Nutrition Examination Survey. Setting the former as baseline, we computed the haldane for each outcome for each racial/ethnic group for each survey, overall and stratified by family income quintile.

Results: For height, high rates of phenotypic change (haldane ≥ 0.3) occurred chiefly between 1960 and 1980, especially for the Black population in the higher income quintiles. By contrast, for weight, high rates of phenotypic change became evident for both the White and Black populations in the late 1980s and increased thereafter; for body mass index, the shift to high rates of change started in both groups in the late 1990s, especially in the middle income quintiles.

Conclusions: Our results support use of the haldane as a supplemental metric to place changes in population health and health inequities in a larger biological and historical context.


Food Insecurity, Poor Diet Quality, and Obesity among Food Pantry Participants in Hartford, CT

Kate Robaina & Katie Martin
Journal of Nutrition Education and Behavior, forthcoming

Objective: Examine relationships between food security, diet quality, and body mass index (BMI) among food pantry users.

Methods: Convenience sample of 212 food pantry clients in Hartford, CT from June, 2010 to May, 2011. Main outcomes included food security (United States Department of Agriculture module), fruit and vegetable consumption (Block Screener), and BMI (stadiometer and digital medical scale). Chi-square tests, Spearman correlations, and logistic regression models were analyzed.

Results: Over half of the sample (50.5%) had very low food security. Mean BMI was 29.5 kg/m2. Age was positively associated with food security (P < .01). Food-secure participants were twice as likely to eat fruit, vegetables, and fiber as food-insecure participants (P = .04). Women were 4 times as likely to be obese as men (P < .01), yet food insecurity was not associated with obesity in this sample.

Conclusions and Implications: Ensuring the nutritional adequacy of donated food is an important consideration for food donors and pantry staff.


Assessing the potential effectiveness of food and beverage taxes and subsidies for improving public health: A systematic review of prices, demand and body weight outcomes

L.M. Powell et al.
Obesity Reviews, forthcoming

Taxes and subsidies are increasingly being considered as potential policy instruments to incentivize consumers to improve their food and beverage consumption patterns and related health outcomes. This study provided a systematic review of recent U.S. studies on the price elasticity of demand for sugar-sweetened beverages (SSBs), fast food, and fruits and vegetables, as well as the direct associations of prices/taxes with body weight outcomes. Based on the recent literature, the price elasticity of demand for SSBs, fast food, fruits and vegetables was estimated to be -1.21, -0.52, -0.49 and -0.48, respectively. The studies that linked soda taxes to weight outcomes showed minimal impacts on weight; however, they were based on existing state-level sales taxes that were relatively low. Higher fast-food prices were associated with lower weight outcomes particularly among adolescents, suggesting that raising prices would potentially impact weight outcomes. Lower fruit and vegetable prices were generally found to be associated with lower body weight outcomes among both low-income children and adults, suggesting that subsidies that would reduce the cost of fruits and vegetables for lower-socioeconomic populations may be effective in reducing obesity. Pricing instruments should continue to be considered and evaluated as potential policy instruments to address public health risks.


Accounting for Product Substitution in the Analysis of Food Taxes Targeting Obesity

Zhen Miao, John Beghin & Helen Jensen
Health Economics, forthcoming

We extend the existing literature on food taxes targeting obesity. We systematically incorporate the implicit substitution between added sugars and solid fats into a comprehensive food demand system and evaluate the effect of taxes on sugars and fats. The approach conditions how food and obesity taxes affect total calorie intake. The proposed methodology accounts for the ability of consumers to substitute leaner low-fat and low-sugar items for rich food items within the same food group. We calibrate this demand system approach using recent food intake data and existing estimates of price and income elasticities of demand. The demand system accounts for both the within-food group substitution and the substitution across these groups. Simulations of taxes on added sugars and solid fat show that the tax impact on consumption patterns is understated and the induced welfare loss is overstated when not allowing for the substitution possibilities within food groups.


Changes in Metabolic Syndrome in American and Korean Youth, 1997-2008

Soo Lim et al.
Pediatrics, forthcoming

Background: Metabolic syndrome (MetSyn) in children and adolescence is increasing worldwide; however, its pattern may be different between Asians and Americans. We compare the prevalence and patterns of MetSyn between American and Korean children and adolescents between roughly 1998 and 2007.

Methods: Data from the American and Korean versions of the NHANES (NHANES and KNHANES) were used for this study. The main outcome is prevalence and pattern of MetSyn among participants separately in each country. In each survey, stratified multistage probability sampling designs and weighting adjustments were conducted to represent the entire population. The revised National Cholesterol Education Program criteria were used to define MetSyn.

Results: Totals of 934, 1781, and 1690 Americans aged 12 to 19 participated in NHANES 1988-1994, NHANES 1999-2002, and NHANES 2003-2006, respectively; and 1225, 976, 705, and 456 Koreans aged 12 to 19 have participated in KNHANES 1998, 2001, 2005, and 2007. The age-adjusted prevalence of MetSyn in American NHANES decreased from 7.3% to 6.7% and 6.5%, whereas in Korean NHANES there was an increase from 4.0% to 5.9%, 6.6%, and 7.8% in each country's respective study. Increases in dyslipidemia and abdominal obesity contributed to the increased prevalence in Korea, whereas in the United States, decreases in low high-density lipoprotein cholesterolemia and high blood pressure contributed to a decreased prevalence.

Conclusions: Considering different phenotype changes, different approaches should be conducted at the national level to reduce the burden and consequences of MetSyn between Korea and the United States.


The Causal Effect of Education on Body Mass: Evidence from Europe

Giorgio Brunello, Daniele Fabbri & Margherita Fort
Journal of Labor Economics, January 2013, Pages 195-223

We adopt a multi-country setup to show that years of schooling have a causal protective effect on the body mass index of females living in nine European countries. No such effect is found for males. The protective effect for European females is not negligible but is smaller than one recently found for the United States and stronger among overweight females. We discuss possible mechanisms justifying both the protective role of education and the gender difference in this role. We argue that the effects of additional schooling on income, the probability of employment, and the frequency of vigorous physical activities, both on and off the job, may help explain our results.


Price and Expenditure Elasticities for Fresh Fruits in an Urban Food Desert

Dave Weatherspoon et al.
Urban Studies, January 2013, Pages 88-106

This study addresses the knowledge gap concerning the demand for fresh fruit in an urban food desert, where healthy foods are scarce by definition. Using register data from a non-profit greengrocer in Detroit - one of America's largest and most severe food deserts - expenditure and price elasticities of fresh fruits are estimated. The results show that, if urban food desert consumers are given access to normally priced produce of acceptable quality, they will purchase it. Expenditure was found to play a major role in determining fruit demand. The food desert consumers were also found to be more price responsive than the average US consumer. The policy implications are clear: introducing neighbourhood stores providing access to good quality produce at competitive prices could be an important component of increasing fruit consumption.


Native American Embodiment of the Chronicities of Modernity: Reservation Food, Diabetes, and the Metabolic Syndrome among the Kiowa, Comanche, and Apache

Dennis Wiedman
Medical Anthropology Quarterly, December 2012, Pages 595-612

As a physical embodiment of modernity, the prevalence of obesity, diabetes, and the metabolic syndrome (MetS) among Native Americans reflects their body's biological response to social and cultural structures that routinize daily behaviors and contain their physical body. This article explains why Native Americans were one of the earliest populations manifesting this epidemic. Ethnohistorical methods identify the conjuncture of chronic behaviors among Kiowa, Comanche, and Apache of Oklahoma that promote inactivity, overnutrition, and psychosocial stresses. Correspondence and primary documents of Federal Indian Agents who managed the reservation food rations and annuity systems beginning in the 1860s, details a culture history of nutrition and food technologies that standardized and established the unhealthy modern diet that continues among Native Americans today. By identifying structural chronicities affecting specific populations and life situations, policies and interventions can be more effective in promoting positive changes for reducing the global pandemic of diabetes and MetS.

By KEVIN LEWIS | 09:00:00 AM