Reviews by Daniel Suter
Lee H. The role of local food availability in explaining obesity risk among young school-aged children. Social Science & Medicine. 2012.
In this paper, Lee attempts to addresses the question of whether or not the type of food stores available in different neighborhoods have an affect on child obesity disparities along socioeconomic and racial lines. She does this by analyzing the BMI and socioeconomic results of a longitudinal national survey of U.S. children in elementary school in comparison with a comprehensive database on food businesses during the same time period of 1999-2004.
The Early Childhood Longitudinal Study-Kindergarten cohort (ECLS-K), a national survey that followed a cohort of kindergarteners through their fifth year of elementary school, was used to follow child BMI as well as school and neighborhood measures over the five years. Data from the National Time Series Establishment (NETS), a comprehensive business establishment database, was then incorporated into her analysis to examine how measures of food outlet availability related to: 1) child neighborhood demographics and 2) changes in child BMI over time.
The study provided a number of very interesting primary and secondary
results. Lee found that the average BMI increased by was 4.76 points over the five years, but that the increase was significantly higher for poor (7.01 points), black (7.85), and Hispanic (5.88) minority children. While she found
that low income and non-white areas had greater access to fast-food establishments and convenience stores—which have been classed as lower quality food sources—they also had significantly greater access to higher-quality food sources such as large-scale grocery stores and full-service restaurants. Interestingly, she also found that in more affluent and majority white neighborhoods, the proportion of restaurants that were considered ‘fast-food’ was actually greater than in lower income neighborhoods. She used a number of statistical models to analyze the data and as reported in the paper, the results of all models implied that‘children who experience greater exposure to fast-food or convenience food establishments in their home neighborhoods are no more likely to gain excess weight than their counterparts who experience less exposure.’ Some of the interesting secondary findings included: maternal education at the Bachelor’s level and above had a protective effect on weight gain over time; poor self-reported parental health was associated with higher risk of child BMI gain; Television viewing was a significant predictor of weight gains; Higher physical activity levels were associated with reduced BMI gains.
While the study did have some limitations, the general conclusion that socio-demographic characteristics of children, families and home behavior appear to be more relevant predictors of unhealthy weight gain than access to higher quality food establishments seems to be well supported.
An R, Sturm R. School and Residential Neighborhood Food
Environment and Diet Among California Youth. Am J Prev Med. 2012.
This study investigates the relationship between food environment and consumption and BMI patterns among Californian youth. The data came from the 2005 and 2007 waves of the California Health Interview Survey, which conducted interviews with adults, adolescents (12-17 yr) and parents of children (0-11 yr). The primary variables used for this study were the self-reported adolescent and parent-reported child consumption of fruits, vegetables, juice, milk, soda, high-sugar foods and fast foods on the day before the interview. Self or parent-reported height and weight was used to calculate BMIs.
The neighborhood food environment was determined using food outlet data from the InfoUSA business database. Food business density was analyzed at varying distances (0.1-1.5 miles) from both the child’s home and school and food store types were rated on a scale of increasing quality from fast-food restaurant to large supermarkets.
The authors studied consumption levels of the various food types as a
function of the food environment, which was determined by proximity to the
various food store types. The main result of the study was a lack of any significant correlation between child and adolescent food consumption patterns and food environment. Similarly, no correlation was found between food outlet type and child/adolescent BMI percentiles. Subgroup analyses were performed for boys and girls and for urban and rural areas and still no correlations were found. A separate analysis found that adolescents (12-17 yrs) consumed significantly more soda, high-sugar foods and fast food than did children, although daily consumption of fruits, vegetables and juices was similar. Interestingly, the study also found that gender, age and parents’ BMI were consistently correlated with students’ BMI percentile.
The study has a number of potential limitations, most significantly the reliance on self and parent-reporting of food consumption patterns and height and weight. It should also be noted that when asking about food consumption, ‘one serving’ of food was self-defined. For parents of children ‘one serving was defined as ‘the child’s regular portion of this food,’ and for adolescents it was defined as‘whatever it means to you.’ This level of subjectivity could have led to somewhat distorted results. That said, the idea that food consumption patterns are not strongly correlated with the immediate food environment is an important one for us to keep in mind when considering influences on childhood obesity.