Childhood Obesity in the Greater Chicagoland Area: A Geographical & Social Analysis By Mei Yan Yuen An Undergraduate Thesis Submitted in Partial Fulfillment for the Requirements of Bachelor of Arts in Geography and Earth Science Advisor: Professor Devonee Harshburger Dr. Wayne Thompson Carthage College Kenosha, WI April 2010 ABSTRACT Obesity in young children is becoming a problem and it is growing rapidly. This thesis focuses on childhood obesity in greater Chicagoland, which includes Cook and Lake County, Illinois, and Kenosha County, Wisconsin. There have been significant changes to the lifestyles and diets of all age groups, most importantly children. Childhood obesity is a factor that can be tied to many other diseases later in life such as diabetes, heart disease and others. This study explores how childhood obesity has been increasing and what factors contribute to its growth. Data analysis includes demographics of the people within the Chicagoland study area and application of social theories is used to explain why a certain area may be more affected by unhealthy weight in their younger population. SPSS and GIS (Geographic Information Systems) is utilized for data analysis. Hot spot analyses in GIS are to identify the most affected areas in southeastern Wisconsin and northeastern Illinois and how these may correlate to demographically at-risk populations. Through analysis and mapping it is concluded that education is the most important factor, followed by race and income. The most vulnerable areas for childhood obesity is centered around metropolitan areas of Chicago and Waukegan, as they move farther away from the center of the city vulnerability is decreased. Social disorganization of neighborhood that surrounds these cities is used to explain the high cases of childhood obesity. ii Table of Contents List of Figures iv List of Tables v Introduction 1 Methodology 15 Study Area 15 Sample Population 15 Data Acquisition 16 Statistical Analysis 19 Spatial Analysis 20 Results 23 Discussion 39 Future Research 41 Conclusion 42 Acknowledgements 43 Reference 45 iii List of Figures Figure 1: Body Mass Index (BMI) graph for boys, example for 10-year old boy (CDC.gov) Figure 2: Body Mass Index (BMI) graph for boys, comparing same BMI with different ages (CDC.gov) Figure 3: Obesity through the years, changes from different studies (Ogden & Carroll, 2010). Figure 4: Natural Areas and Urban Zones as Depicted by Faris & Dunham (Traub & Little, 1980). Figure 5: Visualization of Moran’s I Cluster (ESRI (1) n.d.). Figure 6: Visualization of Getis Ord Gi* (ArcGIS Help Menu). Figure 7: Results from Moran’s I Spatial Correlation of Childhood obesity Figure 8: Scatterplot to show age distribution of obese children population. Figure 9: Race distribution of childhood obesity. Figure 10: Scatterplot of percentage under poverty level (Census 2000) and percent population with childhood obesity. Figure 11: Scatterplot of percentage with low educational attainment, high school diploma (equivalent) or less and childhood obesity. iv List of Tables Table 1: Pearson’s Correlation test for all variables obtain from NHANES dataset, analyzed in SPSS. Table2: Age distribution of sample set and compared to obese children (BMI over 24) (NHANES data) Table 3: Age distribution regression test. (NHANES data) Table 4: Race and childhood obesity distribution by raw number and percentage (NHANES data) Table 5: Race and childhood obesity regression analysis model summary (NNANES data) Table 6: Race Regression Test (NHANES data) Table 7: Income and childhood obesity regression analysis model summary (NHANES data) Table 8: Food Security and BMI of children regression model summary (NHANES data) Table 9: Regression model summary for all NHANES variables Table 10: Regression analysis for all NHANES variables used Table 11: Pearson Correlation for childhood obesity with poverty level, and education (Census data by block group). Table 12: Percentage of block group with poverty status and percent childhood obesity regression model summary (Census) Table 13: Percentage of block group with poverty status and percent childhood obesity regression analysis. Table 14: Percent with low educational attainment and childhood obesity regression model summary (Census) Table 15. Percent with low educational attainment and childhood obesity Regression analysis v CHILDHOOD OBESITY IN THE GREATER CHICAGOLAND AREA: A GEOGRAPHICAL & SOCIAL ANALYSIS Obesity is not a new problem nor has it been ignored. It has been on the minds of the nation for many years and is a growing public health issue. Obesity in the United States has been an increasing problem for all age groups, but most importantly the youth. The health of the young is slowing spiraling downward. In the last twenty years, obesity rates among children have doubled (Brown, et al. 2008). The statistics show that obesity will soon overtake cigarette smoking as the number one cause for preventable deaths in the United States (Terrell 2006). In order to have a strong youth that can contribute to a better future we must have a healthy population. The epidemic may be stemming for changes in diets and activities. These both derive from the social and spatial changes of our nation. BACKGROUND Measuring BMI: tool for identifying obesity In the United States, obesity is measured by weight and height. The measurement is then calculated to a Body Mass Index or BMI. This method is but one screening tool to identify possible weight problems in adults and children. It is a relatively easy measure for a clinical worker to begin the process of identifying obesity but is only determined with further assessment from a healthcare provider. The definition of overweight and obese differs by age and sex. For adults 20 and older, BMI under 18.5 is underweight, 18.5-24.9 is normal 25.0-29.9 overweight and 30.0 is obese. 1 For the younger population there is a slight difference between these measurements since it accounts for variables of differing stages of childhood development. (Center for Disease Control and Prevention (1) 2009). For children there is a growth chart and for both males and female children. The BMI is then plotted on this chart to determine if the child is either underweight, healthy weight, overweight or obese. They are ranked by percentiles and are relative to the child’s age and sex. Underweight is classified as being less than the 5th percentile, healthy weight is 5th percentile to less than the 85th percentile, overweight is 85th percentile to less than the 95th percentile, and obese is calculated at equal to or greater than the 95th percentile. This form of measuring BMI and percentile ranking begins at the age of two and continues through twenty years of age (Center for Disease Control and Prevention (1) 2009). Figure 1: BMI Graph for boys, showing example of how to measure BMI for a 10-year-old boy. (CDC.gov) The following figure is an example of the graph that is used for boys. Figure 1 shows the percentiles and provides an example of how a 10year old-boy would be placed on the chart according to the BMI he had at that age. Figure 2 describes how another boy with the same BMI but older would vary from the first child. This chart and measurement system 2 takes into account age which an adult BMI calculator doesn’t. This is very important because children are constantly growing and changing which does not allow for one single measurement to be applied to all ages. An example would be a 15-year-old who is heavier, however this Index understands that at this age newly developed muscles and other factors play a role in the weight gain (Center for Disease Control and Prevention (1) 2009). Again, BMI is not a diagnostic tool. Instead it is directional and indicates the child might need to be further evaluated. So if a child has a high BMI for his or her age Figure 2: Comparing same BMI with different ages. (CDC.gov) and sex, excess fat still needs to determine. Health care providers have to perform further tests such as skin-fold thickness measurements, evaluation of the child’s or teen’s diet, physical activity, family history, and other appropriate screenings (Center for Disease Control and Prevention (1) 2009). 3 Over the years, the United States has had a steady increase of people being categorized as overweight or obese. According to the CDC there has been an increase in obesity in children 2-19 years of age through the years of 1976 to 2008. Data collected from years of 1976-1980 and 2007-2008 are compared and show that: in pre-school children age 2-5 there was an increase from 5.0% to 10.4%, younger adolescents aged 6-11 went from 6.5% to 19.6% and older adolescents aged 12-19 had an increase from 5.0% to 18.1%. Percentages are respectively shown to the years listed above (Ogden & Carroll, 2010). Figure 3: Obesity through the years (Ogden & Carroll, 2010). 4 Obesity’s Long-Term Affects Being overweight or obese is one of the top ten health indicators according to the Healthy People 2010 (Hedley, et al. 2004). Obesity at a young age can be a contributor to other long-term illnesses and disease. It has been linked to degenerative diseases such as heart disease, diabetes, sleep apnea, asthma and psycho-sociological risks (Nestle and Jacobson 2000). Heart disease and diabetes have high medical and social costs. These disease cost Americans millions of dollars in tax money to treat, which makes obesity not only a medical and social problem but an a contributor to an economic problem (Nestle and Jacobson 2000). There have been some efforts to halt the growing problems of obesity but many are often too drastic and have proven inadequate because many viewpoints and behaviors of diet and foods are rooted into the culture and lifestyles of people (Nestle and Jacobson 2000). Built Environment & Crime A drop in physical activity and increase in sedentary activities has been a major change that has affected the youth. Technological changes make it more comfortable to stay indoors with more things to do including and not limited to cable television, internet, and video games. Since there are more indoor sedentary activities these results in less outdoor activities, this is contributing to increased weight. Areas with neighborhood crime and road safety are negatively correlated with physical activity. Access to safe play environments, such as at schools, show a correlation to increased physical activity. This is also rooted into the parental perceptions of crime in their neighborhood (Brown, et al. 2008). 5 Minority & Socio-Economic Status Children are more likely to become obese if they have a background as an ethnic minorities and low-income, than children of non-minority status (Kumanyika and Grier 2006). Girls of lower socio-economic parents had a higher risk of become obese compared to the girls of higher socio-economic status parents (Morgan, et al. 2010). There are many socio-economic and demographic variables that contribute to this. Socioeconomic status is defined by the social class, family income, parental education level, occupation and social status in their community (North Central Regional Educational Laboratory n.d.). As explained earlier, sedentary activity comes from changing lifestyle patterns and also may be related to perception to crime rates which have a negative effect on outdoor activity levels. People of lower socioeconomic status are more prone to live in areas with high crime rates and poor built environment. There are fewer areas of safe play areas that located in a community of low economic status. Parents may restrict their children’s outdoor activities for safety reason. Along with this analysis other socio-economic variables must be taken into account that is affecting physical activities. These variables could be rooted into the family’s work schedule, money and car ownership which can be factors in children being involved with recreational activities or sports to keep the young active (Kumanyika and Grier 2006). Other factors can include the exposure of media and commercials to young children from greater amounts of television watching. Ethnic minorities and low-income youth are exposed to a large number of food advertisements due to the increased amount of television watching compared 6 to white, non-poor children, which can affect the food preference and perception (Kumanyika and Grier 2006). Food Deserts Although the United States is considered one of the most developed countries in the world, food deserts still exist (Center for Disease Control and Prevention (2) 2010). There isn’t a standard definition for a food desert, but according to the US Department of Agriculture there are still pockets of population living in the United States that have limited ability to access to affordable and nutritious food, such as, fruits, vegetables, whole-grains, low-fat milk and others from a well-balanced diet. These populations live far from a supermarket or large grocery store and have a little access to reliable transportation. Communities high in ethnic minority and low-income children are affected by having fewer average supermarkets and convenience stores that stock fresh, good quality, and affordable foods (Hedley, et al. 2004). It is also noted by Kumanyika and Grier (2006) that neighborhoods where low-income and minority children live have more fast food restaurants that contain high-fat and high-caloric foods and fewer healthy food vendors than wealthier or predominately white communities. Similar to “white-flight” where Caucasians fled areas that were homes to African Americans and other minority groups, there was a “supermarket flight,” where supermarkets fled the inner cities and left primarily low-income neighborhoods for high-income areas, leaving the low-income neighborhoods with 30 percent less supermarkets than high-income neighborhoods (Hedley, et al. 2004). It is suggested by many scientific studies that food 7 deserts negatively affect the health outcomes of the population (Center for Disease Control and Prevention (2) 2010). Weight-gain is caused by more calories ingested than burned; the calories from nonnutritious foods are often substituted for a well-balanced diet. There have been many studies that demonstrate that food deserts are more frequently in areas with high poverty levels and food insecurities. A study done in Pennsylvania, with an analysis done with Geographic Information Systems was used to identify food deserts in school districts (Schafft, Jensen and Hinrichs 2009). This analysis concluded that there are higher percentages of school districts with populations located within food deserts are more likely to be socially and economically disadvantaged. They also found that there is an increased rate of children being overweight and obese that resides in a food desert (Schafft, Jensen and Hinrichs 2009). Food Stamps In the United States, people that need assistance with purchasing food are provided funds through the USDA Food Stamp Program. The program provides low-income households the funds to purchase foods at a grocery store. It began in the 1960’s and expanded in the 70’s due to the under consumption of food and nutrients in America (Ploeg and Ralston 2008). This provided the opportunity for people with low-income or poverty status to purchase healthier food choices. However, this did not assist with transportation to grocery stores. Today it is called SNAP or short for Supplemental Nutrition Assistance Program. SNAP is available to assist those that fall 100 percent beneath the poverty line and for elderly or disabled members. To qualify for SNAP a person must have a gross income that is below 130 8 percent the poverty line. Eligibility is based on both financial and non-financial factors. People must complete and file a form, go through an interviewing process to verify facts in order to be determine eligibility. Funds are supplied in the form of an electronic benefit transfer or EBT, instead of coupons that were given out in the past (Food Reseach and Action Center 2010). Things that can be bought with food stamps include food and for plants and seeds to grow food for the household to eat. The funds are not able to be used on non-foods such as pet food, soap, paper products, etc. They cannot be used for alcoholic beverages or tobacco, vitamins or medicine, food eaten at the store or hot foods such as made and ready to eat meals (United States Department of Agriculture 2010). However, this does not prohibit the purchase of foods high in sugar and saturated fats. This can include items like soda, chips, and frozen foods, which can contribute to higher caloric intake. There have been numerous studies that link food stamps to obesity. White women living in poverty are more likely to be obese compared to black or Hispanic males (Ploeg and Ralston 2008). This could be because women are more likely to have sedentary activities than men. Further, if they are unemployed, they are less likely to participate in high physical activities. Women that are linked to long term use of food stamps, are found to have higher chances of becoming obese upward of 20 to 50 percent increase in obesity rates (Ploeg and Ralston 2008). Ploeg and Ralston did not find that adolescent children were linked to higher rates of obesity and food stamps in either teenage boys or girls. In a different study, there seems to be a correlation between long-term food stamps participants and overweight in lowincome young daughters and their mothers (Ploeg and Ralston 2008). 9 Perception & Education of Parental Figures Perception and the role of education play an important role on parents and obese children. Low-income mothers have a higher probability that they will not pursue higher education. They have less understanding regarding the health of children and what is good for them. They often perceive that their child is not obese unless they are made fun of for their weight or are less active or obesity which affects their physical activity. Only 11 percent of mothers without college education, thought their pre-schooler was overweight (Jain, et al. 2001). Mothers are critical players and mediators for preventing obesity in their children because they have a large responsibility to shape the diet and activity pattern of their young children (Jain, et al. 2001). Obesity also affects college enrollment for women (Crosnoe 2007). Theoretical Considerations in the Study of Childhood Obesity Conflict Theory Childhood obesity has not been studied and put under a sociological perspective and theory. This thesis will try to address this omission. Conflict theory might be one of the best ways to analytically frame childhood obesity. The conflict perspective targets the issue of the continuous power struggles for control of scarce resources (Kendall, 2007). Karl Marx was a key player in using conflict theory to shape this perspective. He focused on the power struggle between people with control of the means of production and those without it, and the exploitation of the oppressed by the people holding power (Kendall, 2007). Conflict theory can also be applied to things such as suicide or feminism. In this study, we will use it to apply and explain childhood obesity that is being caused by low socioeconomic status. 10 Social Disorganization Robert E.L. Faris and H. Warren Dunham were theorists that incorporated social disorganization and urbanism. Rural-urban comparisons of dependency, crime, divorce and desertion and suicide are more prominent and severe in the cities. (Traub & Little, 1980). The concepts of the city is that the farther one moved away from the center of the city or concentric zones (distinct areas or circles that radiated from the central business district) the fewer social problems were found. The basic idea was that the growth of the city, location of areas, and social problems were not random but a part of a pattern (William & McShane, 1999). The first zone is the central business district, where businesses and factories were located and very few residences exist. The next zone was called zone of transition. This zone was not a desirable living location. However it was the cheapest location due to its deterioration. Immigrants usually settled in these areas because it was inexpensive and near factories that they could find work. As these members of the zone of transition moved up on the social ladder they moved to the third Figure 4: Natural Areas and Urban Zones as Depicted by Faris & Dunham (Traub & Little, 1980). zone called the zone of workingmen’s homes. When they moved out another wave of 11 immigrants take their spot in the zone of transition (William & McShane, 1999). Social Stratification William Julius Wilson is a sociologist that emphasizes that race is not the main factor when it comes to social problem but it is more importantly about social class. He says that social problems of urban life measures the problems of racial inequality (Wilson, 1987). In addition, he argues that when industrialized work disappears from inner cities, and work disappears there is a urban unemployment increase. Which leads to people in the inner-city to not have any social class movements, and they are immobilized in the stratification of class and location. When there is disorganization within the neighborhood. This leads to crime, low education, female-headed households and teenage pregnancy (Wilson, 1987). For Wilson, he focus on how the economic change of a location plays a greater role in negative outcomes in an area. Housing, employment and economic activity, education and other factors that relates to negative outcomes. Summary A change in diet and lack of physical activities over time in children had been a social and medical epidemic resulting in children to become more overweight and obese. There are many negative socio-demographics and socio-economic factors that contribute to the increased number of children being categorized as overweight or obese. Minority status that affects financial difficulties plays an enormous role in higher rates of childhood obesity. People that fall under the poverty line and those that are unemployed 12 are more likely to live in poorly built environments. They are also more likely to live in areas with higher crime and drug use areas and may be more fearful of letting their children do much needed outdoor activities. They are then more likely to keep their children safely inside the home. Unfortunately this will lead to activities that are less physical and in turn have a higher likelihood of television watching, video games, and internet among other sedentary activities. Food stamps have shown mixed results in its ability to provide people that fall below the poverty line a way to obtain healthy foods which they are unable to buy without it. It provides families a chance to purchase a healthier diet, although food stamps have few exceptions on what it can be used for. Unfortunately, there are still people in the United States that have minimal means to visit a full line grocery store. It is still accepted to buy foods high in sugar, saturated fats, sodium, and many others that contribute to unhealthy diets. So, although a mother or responsible member has the ability to purchase fresh and healthier choices, old habits and choices made prior to assistance through food stamps could affect their preference of foods. Significance of Study Childhood obesity is not just what is consumed in the body but the behaviors that lead to what is put in the body and what is done to maintain a healthy weight or not. There is little social interpretation found on this issue. This study’s goal is to contribute to the sociological world a start to understanding how social and geographical location is affecting childhood obesity today. By understanding why and where, it can be more effort to provide these areas 13 with more assistance or further try to understand why some population are more at risk than others. Hypotheses Null Hypothesis Socio-demographic and socio-economic factors does not increase the rate of childhood obesity. Alternative Hypothesis Negative socio-demographics and socio-economical is associated with the increase number of children categorized as overweight or obese. Sub-Hypotheses A. Minority race (mainly Hispanic and African American) is associated with higher childhood obesity compared to non-minority races. B. Low income is associated with higher rates of childhood obesity. C. Households that are unable to afford a balanced meal are associated with higher rates of childhood obesity. D. Lower levels of education (high school diploma or less) are associated with higher rates of childhood obesity. 14 METHODOLOGY Study Area The study consists of Greater Chicagoland counties from Illinois and Wisconsin. Cook, Lake, and Kenosha County are studied at the block group level, which is defined by the U.S. Census Bureau as a cluster of Map 1 census blocks that share the same first digit of their four-digit identification number within a census tract. These block groups never cross state, county, or other similar boundaries (U.S. Census Bureau, Geography Division Cartographic Product Management Branch 2005). Within the three counties, there are 4,748 block groups. Sample Population Childhood Obesity for this analysis is children ages 2 to 16 years of age. Ages 0 to 1 are excluded because body mass index was not measured or insufficient for this age group. 15 Overweight and obese were defined at BMI’s over 24. This is the starting point for 16 year olds to be considered overweight. Data Acquisition Two data sets from the Census Bureau and the Center for Disease Control (CDC) would be utilized for examining childhood obesity. These data sets and its information will go through extensive analysis and modeling. The data acquired from the U.S. Census Bureau will contain demographics such as race and income level. From the CDC, the National Health and Nutrition Examination Survey (NHANES) is used for health data and BMI measurements. NHANES NHANES program, which began in the early 1960’s, is designed to assess the health and nutritional status of adults and children in the United States. It is a survey that combines the use of interviews and physical examinations. This is done by surveying a nationally representative sample of about 5,000 people each year. The interviews include demographics, socioeconomic, dietary, and other health related questions. The physical examination uses the combination of medical, dental, physiological measurements and laboratory tests that are administered by the medical personal. NHANES is a major program that is part of the National Center for Health Statistics, which is a part of the CDC. The CDC’s responsible to produce and provide information to the nation about vitals and health statistics (Center for Disease Control (3), 2009). 16 Data was aggregated from the data set. Variables that were used from NHANES: 1: Body Mass Index (BMXBMI) Body mass index was calculated for immediate use. BMI will be utilized as our dependent variable. At times, it would be used as is, when identifying childhood overweight and obese population, this sample will be queried to BMI over 24. This is a number that is average for most older age groups but is overweight or obese for any of the ages between 2 to 16. 2: Age at Screening Adjudicated (RIDAGEYR) The NHANES provides a wide sample of ages to represent the United States. Since this study is on the children population only, an age group of 2 thru 16 was queried. BMI starts being measured at the age of two. There was insufficient data for age one and no data was available for age group of zero. Age was measured every whole year. 3: Annual Household Income (INDHHIN2) Annual Household Income was measured and coded in unequal groups. The original data was coded: 1) $0-4,999; 2) $5,000-$9,999; 3) $10,000-14,000; 4) $15,000-19,999; 5) $20,000-24,999; 6) $25,000-34,999; 7) $35,000-44,999; 8) $45,000-54,999; 9) $55,000-64,999; 10) $65,000-74,999; 12)Over $20,000; 13) under $20,000; 14) $75,000-99,000; 15) over $100,000. This was re-coded to: 1) $0-14,999; 2) $15,999-24,999; 3) $25,000-34,999; 4) $35,000-44,000; 5) $45,000-54,999; 6) $55,000-64,999; 7) $65,000-74,999; 8) $75,000-99,000; 9) Over $100,000. 17 4: Race/Ethnicity (RIDRETH1) Race was nominally measured. It was coded by NHANES as 1) Mexican Americans; 2) Other Hispanics; 3) Non-Hispanic White; 4) Non-Hispanic Black; 5) Other Race and Multiple Race. The categories were re-issued to make a series of “dummy” variable. Each race was categorized individually and coded 0 and 1. When the case was true for that race it was issued a one and when false it was issued a 0. This was completed in SPSS by writing syntax. 5: HH (Household) Couldn’t Afford Balanced Meals (FSD032C) This variable is useful for our study to measure food security/ food scarcity. Throughout the report this variable will be mentioned as either food security or food scarcity. This variable is associated and can provide a way to measure food stamps usage and the diets indirectly. But information and results collected can be a key to understanding underlying issues. The question to respondents was “Household couldn’t afford a balance meal”, their possible responses were/coded 1) Often true; 2) Sometimes True; 3) Never True. Census Data Data from Census 2000 was utilized for block group level data. This is the most current full census data that is available. Variables used at block group level: Sex by Educational Attainment for the Population 25+ years (P37) and Poverty Status in 1999 by Age (P87). Education was re-coded to population with a high school diploma/equivalent and less. This variable was converted into a percent by dividing it by the total population of the block group. The poverty status variable provided a total number of people that fell under the poverty level. 18 This was also converted into a percentage by dividing the number of people that fell below the poverty level and the total sample size. This information was used for the spatial analysis and also utilized in SPSS to measure correlation and regression test. Statistical Analysis Microsoft Excel and SPSS (Statistical Package for Social Sciences) were utilized for statistical analysis for the various data. Microsoft Access was used as a helping tool to connect the variables and aggregate the data. Access was also used to convert table data to databases that are able to be joined and used in ArcGIS (spatial analysis tool). Excel and SPSS were used to construct charts to showing relationships, correlations and regressions. Correlation and regression test provide a statistical significant values or p-values (when necessary and obtainable), test are only significant at p ≤ .05. Regressions are identified with a strong correlation with R values over .7. However, the value is accepted to be lower when examining human behavior. Using standardized regression coefficients (betas), we can assess the relative importance of the independent variables in predicting the dependent variable, in this study childhood obesity or BMI. The larger the beta values the higher the importance. Variables analyzed with regressions (with graphs) and correlations with Excel in this study were: age & childhood obesity and income & food scarcity. Race and childhood obesity was examined with percentages and bar chart to display data. Data analyzed in SPSS were transported from with spatial data. This omitted the issues of pairing BMI’s with the population weights provided from NHANES data set. The variables that were investigated and analyzed in 19 SPSS were: childhood obesity & poverty levels and childhood obesity and education level of high school diploma (or equivalent) or less. These variables have statistical test of correlation and regressions (with graphs) as well. Spatial Analysis Geographic Information System (GIS) will be utilized to perform spatial analysis of the NHANES data. GIS is a mapping tool that integrates data and used to manage, analyze, and display data spatially. GIS allows data to be visualized, understood spatially, questioned, and interpreted. Explorative mapping will be done, including densities of childhood obesity. Modeling Data The counties will be broken down to block groups. Block groups are defined by the U.S. Census Bureau, as clusters of census blocks that have the same first digit within a census tract (U.S. Census Bureau, Geography Division Cartographic Product Management Branch 2005). However, the NHANES data does not have location data, so the data had been modeled. The modeling of the NHANES data is done by allocating obesity data out to census block groups using the available weights in the data set. They are weights assigned to each record that will be modeled out to the population by percentages of race and number of children in those race categories. The data is then proportioned to the entire nation by block groups. 20 Moran’s I Moran’s I and is a spatial statistic tools to identify clustering of data. Moran’s I analysis whether the given variable and attribute is Figure 5: Moran's I (ESRI (1) n.d.) clustered, dispersed or random (ESRI (1) n.d.). The test calculates a z-score to identify if the findings are statistically significant or not, in addition with a Moran’s I Index, Expected Index, Variance, and p-value. +1.0 z-score value will indicate high clustering whereas -1.0 z-score value indicates dispersion. Moran’s I is displayed in an output window to summarize the finishing data. Moran’s I analysis is done on the percent of childhood obesity in greater Chicagoland. This analysis will determine if the density map of values percentage of childhood obesity is clustered and the statistical significance of the data. Childhood Obesity Vulnerability Index (COVI) A Childhood Obesity Vulnerability Index is created by giving each variable a percentage that acts as normalization for the block group. The variables consist of childhood obesity (BMI 24 and over), low education (high school diploma (equivalent) or less) and people that fall under the poverty level. The variables will be layered added together called “map algebra” to determine which location is most vulnerable to high childhood obesity rates. This index begins to allow us to identify the most at risk locations, give the ability to understand why these areas may be affected and how we are able to target and provide more information to these areas. 21 Getis Ord Gi* Getis-Ord Gi*, sometimes known as hotspot analysis, will be utilized in ArcGIS Spatial Figure 6: Getis Ord Gi* (ArcGIS Help Menu) Analyst extension. This tool identifies statistically significant spatial clusters of high values (hot spots) and low values (cold spots). It returns with the z-score and p-value, which measures statistical significance to determine whether or to reject or fail to reject the null hypothesis. High z-score and low p-value signify a spatial clustering of high values. A z-score very close to zero would indicate no apparent spatial clustering (ArcGIS Help Menu). Getis Ord Gi* analysis is performed on the Childhood Obesity Vulnerability Index (COVI). This analysis will identify were the hot spots and cold spots are occurring to all three variables combined together. This will further our understanding of patterns of vulnerability for children to become obese. 22 RESULTS Spatial View on Childhood Obesity A density map with graduated colors was created in ArcGIS showing percentage of children ages 2 thru 16 who had a body mass index of over 24 by block group (map 1). The darker the block group indicates a higher percentage of children that are overweight or obese. Moran’s I was executed for this map to find statistically significant clustering of childhood obesity. The data is falling with a standard deviation of over 2.58. The z-score was 327.13 and p-value was 0.000. This means there is less than 1% likelihood that this clustering pattern could be the result of random chance. Figure 7: Moran's I for Childhood Obesity Cluster Analysis 23 Map 2: Density of Childhood Obesity 24 Correlation for BMI and Variables from NHANES (Age, Race, Income, and Food Scarcity) Correlation test was done on the NHANES data set. It includes children ages 2 to 16. All measurements have been normalized for the weights of the population. Table 1 shows the correlations between the variables. Significance test for all correlations with body mass index equaled 0.000. This means the variables are statistically significant. Pearson Correlation identifies if there is a positive or negative correlation between variables and increasing BMI. For age and BMI, Pearson Correlation is .541 which indicates a positive correlation, meaning as children get older, BMI increase. This positive correlation is occurring with people in the race categories of Mexican Americans, other Hispanics and African Americans. A negative relationship is occurring when BMI is correlated with the Caucasian race, household income (as income increases, BMI decreases), and food security. Food Security is coded, 1 for often true, 2 for sometimes true, and 3 for never true. So this correlation is interpreted as food security is as food security is troublesome there is a higher BMI. 25 Table 1: Correlations from NHANES Variables Body Mass Pearson Corr. Index Body Age of Mass Resp. Mex. Other Index (2-16 yrs) Amer. Hisp. 1 Sig. (2-tailed) N 59308752 White Black Househol Food d Income Security .541** .027** .027** -.036** .061** -.071** -.072** .000 .000 .000 .000 .000 .000 .000 59308752 59308752 59308752 59308752 59308752 -.070** -.006** .055** .011** .079** -.019** .000 .000 55694296 59046939 Age of Pearson Corr. .541** Resp. Sig. (2-tailed) .000 .000 .000 .000 .000 (2-16 yrs) N 59308752 67526623 67526623 67526623 67526623 67526623 -.108** -.468** -.171** -.177** -.107** .000 .000 .000 .000 .000 67526623 67526623 67526623 1 -.306** -.112** -.126** -.076** .000 .000 .000 .000 67526623 67526623 67526623 1 -.484** .254** .061** .000 .000 .000 Mexican Pearson Corr. .027** American Sig. (2-tailed) .000 N 59308752 Other Pearson Corr. .027** Hispanics Sig. (2-tailed) .000 N White .000 1 67526623 67526623 -.006** -.108** .000 .000 67526623 67526623 -.036** .055** -.468** -.306** Sig. (2-tailed) .000 .000 .000 .000 67526623 67526623 67526623 67526623 67526623 1 59308752 Pearson Corr. .061** .011** -.171** -.112** -.484** Sig. (2-tailed) .000 .000 .000 .000 .000 67526623 67526623 N Household Pearson Corr. Income -.070** Pearson Corr. N Black 59308752 1 Sig. (2-tailed) N 59308752 63430737 67207540 63430737 67207540 63430737 67207540 63430737 67207540 -.140** -.007** .000 .000 67526623 67526623 67526623 -.071** .079** -.177** -.126** .254** -.140** .000 .000 .000 .000 .000 .000 .000 63430737 63430737 63430737 63430737 55694296 Food Pearson Corr. -.072** Security Sig. (2-tailed) .000 (HH could N 59046939 63430737 67207540 1 63430737 63430737 63430737 -.019** -.107** -.076** .061** -.007** .223** .000 .000 .000 .000 .000 .000 67207540 67207540 67207540 67207540 67207540 .223** 1 63430737 67207540 not afford balanced meal) **. Correlation is significant at the 0.01 level (2-tailed). 26 Age distribution & Childhood Obesity A frequency table was created to compare the sample (N) with the obese sample based on age (table 2). When age is increasing there is an increase of children that have a BMI of 24 or over. This is not surprising since it is unnatural for children at toddler age to have a BMI of greater than 24. Unfortunately, the numbers are not zero for this age group. The age with the most case of childhood obesity is in the 15 year old population (37.8%). A scatterplot (see graph 1) displays the distribution of age and population that is obese. Table 3 shows that adjusted R2=.915, indicating that 91.5% of the variance is number of children with a BMI of over 24 is accounted for by the independent variable, age. Table 2: Age Distribution Age N Population (2-16 Yrs) Obese % 2 4,378,124 11,061 0.3% 3 3,638,527 14,942 0.4% 4 4,651,961 31,844 0.7% 5 3,803,359 119,014 3.1% 6 3,531,059 127,705 3.6% 7 4,145,240 134,416 3.2% 8 4,280,578 330,820 7.7% 9 3,542,921 469,770 13.3% 10 3,797,123 690,981 18.2% 11 4,507,460 897,945 19.9% 12 3,976,810 1,086,447 27.3% 13 3,528,404 999,350 28.3% 14 4,930,447 1,545,393 31.3% 15 4,417,630 1,669,927 37.8% 16 4,748,544 1,532,567 32.3% 61,878,188 9,662,180 15.6% Total Table 3 Regression Statistics (AGE & CHO) Multiple R 0.960 R Square 0.921 Adjusted R Square 0.915 Standard Error 176303.9 Observations 15 27 Figure 8: Scatterplot of Age Distribution in Sample Race and Childhood Obesity A race distribution of the sample was also completed. The sample set reflects the demographics of the United States. Table 4 displays the distribution of race of our raw sample and our extracted obese (BMI over 24) sample. The sample contains 57.7% Caucasian, 14.9% African American, 13.8% Mexican American, 7.0% other & multi race, and 6.5% other Hispanics. Table 4: Race and Childhood Obesity Distribution Population (2-16 Yrs) Race Mexican American Other Hispanic N 8,531,069 % Obese % (obese/N) 13.8% 1,476,863 17.3% 4,048,923 6.5% 745,552 18.4% White 35,728,953 57.7% 5,366,030 15.0% Black 9,212,045 14.9% 1,686,568 18.3% Other & Multi Races 4,357,197 7.0% 387,167 8.9% 61,878,188 100.0% 9,662,180 15.6% Total 28 From this a sample of children with a BMI of over 24 was extracted to compare to the total of all the children in the NHANES sample. 15.6% of children ages 2 to 16 were classified with a BMI of 24 and higher. 18.4% of the total other Hispanic group was considered to be obese. Followed closely by African Americans, which had 18.3% of their children’s population classified as overweight or obese. 17.3% of Mexican American children are overweight or obese. Caucasians came in with 15% of the children are overweight or obese. The last category is other and multi race people that would include populations such as Asians. This group had 8.9% classified in the childhood obesity range. A regression was done in SPSS on racial groups. Table 5 shows that adjusted R2=.010. This indicates that one percent of the variance in childhood obesity is accounted for by the independent variables on race. According to Standardized Coefficients Beta scores in table 6, the most important group to focus on is African American group (Beta=.21, p=.000). Mexican Americans are the next most important (Beta=.10, p=.000), followed by Hispanic group (Beta=0.052, p=.000) and lastly, Caucasians (Beta=.013, p=.000). Table 5: Model Summary Model dimension0 1 R R Square .102a Adjusted R Square .010 Std. Error of the Estimate .010 4.97228 a. Predictors: (Constant), race_dum_black, race_dum_othhisp, race_dum_mex, race_dum_white 29 Table 6: Race Regression Coefficientsa Model Standardized Unstandardized Coefficients B 1 (Constant) White Mexican American Other Hispanic Black Std. Error 27.859 .007 .113 .007 1.175 Coefficients Beta t Sig. 4162.668 .000 .013 16.367 .000 .008 .100 156.278 .000 .838 .008 .052 101.300 .000 2.371 .007 .210 318.668 .000 a. Dependent Variable: BMI over 24 Figure 9: Race and % Childhood Obesity Regression on Income and BMI (NHANES Variables) Regression analysis was completed on NHANES variables of income that was recoded as mentioned in the methodology section and BMI of over 24 (childhood obesity). Table 7 reports 30 R2=.007 with a beta of -.081. This indicates a weak negative relationship that lower income has higher cases of childhood obesity. However, it is still statistically significant (p=.000). Table 7: Income & Childhood Obesity (NHANES) Model Summary Model dimension0 a. 1 R R Square Adjusted R Square Std. Error of the Estimate .081a .007 .007 4.28171 Predictors: (Constant), Household Income Recoded Food Scarcity: Household not able to afford balance meals The final regression was computed on food scarcity and its impacts on Childhood Obesity. Table 8 reports a R2 value of .000. This indicates no relationship between the variables higher BMI and food scarcity issues. Table 8: Food Security & BMI - Model Summary Model dimension0 1 R .021a R Square Adjusted R Square .000 .000 Std. Error of the Estimate 4.25423 a. Predictors: (Constant), Food Security (HH could not afford balanced meal) Regression on All Hypothesized Variables within NHANES Data Variables on race, income and food security were run in a multiple regression against childhood obesity to compare which variables are the most important. Table 9 illustrates the adjusted R2=.046, indicating that 4.6% of the variance in Childhood obesity is accounted for by the independent variables included in this regression. Table 10 shows the beta levels which determine which variables is the most essential, with the highest value being most important. 31 Most important is looking at the African American race (Beta=.220, p=.000). Next in importance is Mexican American race (Beta=.101, p=.000). Followed in importance are Household Income with a negative correlation (Beta=-.083, p=.000). Thereafter, Other Hispanics (Beta=.057, p=.000), Food Scarcity (Beta=.050, p=.000), and lastly Caucasian (Beta=.036, p=.000) came in order of importance. Table 9. Model Summary Model dimension0 R R Square .215a 1 Adjusted R Square .046 Std. Error of the Estimate .046 4.19510 a. Predictors: (Constant), Food Scarcity recoded never true and sometimes/often true, race_dum_othhisp, race_dum_mex, race_dum_black, Household Income Recoded, race_dum_white Table 10. Regression Coefficientsa Model Standardized Unstandardized Coefficients B 1 (Constant) Std. Error 27.483 .010 1.225 .008 Other Hispanics .943 White Coefficients Beta t Sig. 2854.454 .000 .102 153.101 .000 .009 .058 106.880 .000 .311 .007 .036 42.009 .000 Black 2.540 .008 .222 320.931 .000 Household Income -.110 .000 -.083 -233.082 .000 .625 .004 .055 156.700 .000 Mexican American Food Scarcity a. Dependent Variable: BMI over 24 32 Population of Obesity, Poverty Status, and Low Education (High School Diploma or Less) Data on education and poverty status was collected from the Census website. This data was integrated into the block group levels with the childhood obesity spatial model. The education was regrouped to show percent of people that had high school diploma or less (low education), and poverty was also converted into a percentage to normalized for size of block group. This data was then analyzed in SPSS. Correlation and regression of these variables were computed. Pearson Correlation was used to compare the percentage of low education and poverty status with childhood obesity (table 10). Both test had a p-value = 0.000. This indicates both variables are statistically significant and correlate with each other. Table 11: Pearson's Correlation (Census data by Block Group) Correlations: Obesity, Poverty Level, and Education Percent of Percent Population Population with Overweight and High School Obese (BMI Percent Diploma (and over 24) 2-16 Population Under Equivalent) or yrs of age Poverty Level less .433** .634** .000 .000 4746 4746 4746 .433** 1 .508** Percent of Population Pearson Correlation 1 Overweight and Obese (BMI Sig. (2-tailed) over 24) 2-16 yrs of age N Percent Population Under Pearson Correlation Poverty Level Sig. (2-tailed) .000 N 4746 4746 4746 Percent Population with Pearson Correlation .634** .508** 1 High School Diploma (and Sig. (2-tailed) .000 .000 Equivalent) or less N 4746 4746 .000 4746 **. Correlation is significant at the 0.01 level (2-tailed). 33 Regressions and scatterplots were computed for each relationship. Poverty status and childhood obesity has a R-squared value of .188 (table 12). The scatterplot (graph 3) and best fit linear line shows a slight positive correlation. Beta equals .433, with a statistical significance of .000 (table 13). Figure 10: Scatterplot of Poverty Level and Childhood Obesity Table 12: Regression Poverty Status and Childhood Obesity Model Summary Model dimension0 R 1 .433a R Square Adjusted R Square .188 Std. Error of the Estimate .188 3.803 a. Predictors: (Constant), Percent Population Under Poverty Level 34 Table 13: Poverty Status and Childhood Obesity Coefficientsa Model Unstandardized Standardized Coefficients Coefficients B 1 (Constant) Std. Error 13.080 .074 .124 .004 Percent Population Under Poverty Beta t Sig. 176.892 .000 .433 33.107 .000 Level a. Dependent Variable: Percent of Population Overweight and Obese (BMI over 24) 2-16 yrs of age Low education and childhood obesity has a R-squared value of .402 (table 12). The scatterplot (graph 4) and best fit linear line shows a positive correlation. Beta equals .634, with a statistical significance of .000 (table 13). Figure 11: Low Education and Childhood Obesity 35 Table 14: Regression Low Education and Childhood Obesity Model Summary Model dimension0 1 R R Square .634a Adjusted R Square .402 Std. Error of the Estimate .402 3.263 a. Predictors: (Constant), Percent Population with High School Diploma (and Equivalent) or less Table 15: Coefficientsa Model Unstandardized Standardized Coefficients Coefficients B 1 (Constant) Percent Population with High School Diploma Std. Error Beta t Sig. 8.922 .113 78.980 .000 .121 .002 .634 56.431 .000 (and Equivalent) or less a. Dependent Variable: Percent of Population Overweight and Obese (BMI over 24) 2-16 yrs of age Childhood Obesity Vulnerability Index Analysis (COVI) These variables were combined to create a Childhood Obesity Vulnerability Index (COVI) as explained in the methodology (map 2). This map indentifies the most-at risk locations in the Greater Chicagoland area. They are categorized from low to high vulnerability. Dark blue indicates a low concentration of the three variables combined where dark red indicates high concentrations. Getis Ord Gi*, a hot spot analysis tool was also computed with the COVI map. This shows spatial clustering of vulnerability. Dark red indicates hot values (hot spots) and dark blue indicates low values (cold spots). 36 Map 3 37 Map 4 38 DISCUSSION After the analysis of the NHANES data and Census data, there were several main issues to focus on. We reject the null hypothesis that states that socio-demographics and socioeconomic factors do not increase the rate of childhood obesity. The graphs and maps show a great impact of the variables used on childhood obesity. All variables were statistically significant. When age was examined, there is a noted increase in BMI as they got older. This is in agreement with the BMI chart. However, there were some very young children that had high BMI’s of over 24. Although they made a small percentage, there are still 11,061 2 year olds that have a BMI of over 24. It was hypothesized that race would have an impact on the numbers of children that are obese or overweight. From the analysis we see a correlation that would indicate minority races are an important variable when studying childhood obesity. Focus is on the African American and Hispanic populations due to the higher correlation for childhood obesity compared to other races. We fail to reject the sub-hypothesis (A) that minority race (specifically Hispanics and African Americans) is associated with higher childhood obesity compared to non-minority race. Although there was a higher percentages in the “other Hispanic” group, when the multiple regression was ran it showed that African American and Hispanic group was most important when examining race and high BMI. Sub-hypothesis B predicted that low income was associated with higher rates of childhood obesity. This variable was examined in two ways, through raw data on the national 39 level and on a spatial analysis using census data to compare the study area. After examining the NHANES data of income and BMI, there was a very little correlation and relationship between the variables (R2=.007). However, when comparing income of a block group and the NHANES modeled childhood obesity data, there was a higher correlation (R2=.188). This suggests that income characteristic of a location may have an impact on childhood obesity. Sub-hypothesis C stated that households that are unable to afford a balanced meal is associated with higher rates of childhood obesity. After analyzing the data, it seems to have a very weak correlation. However, even though it was weak it was still statistically significant. Since there was a negative but very weak correlation it would indicate that respondents with higher BMI’s answered either often true or sometimes true. The conclusion is to reject the sub-hypothesis C. There is not a significant correlation between food security and childhood obesity. Due to incomplete data acquisition for this variable it could be theorized that this variable did not correlate because of how the question was answered. In addition to there being several versions of this question, it was asked as a negative which may have confused some respondents. Food stamps may also be a benefitting contributor as well. Since lowerincome families are able to obtain food stamps they would be more likely to not answer often true to the question. Hypothesis D stated that lower levels of education are associated with higher rates of childhood obesity. Since the education levels were taken from Census data it was joined spatially to the block groups. The regression showed that education and childhood obesity were correlated (R2=.402, p=.000). The data is interpreted if the block group has a high 40 percentage of people that have only a high school diploma or less they are more likely to be living in an area with high childhood obesity. Childhood obesity is highly clustered. It falls in certain patterns around major cities. This pattern has been observed by sociologist, such as Robert E.L. Faris and Warren Dunham, mentioned earlier. The Childhood Obesity Vulnerability Index (COVI) shows the pattern and areas that are most greatly affected by childhood obesity, poverty, and low education experience. Faris’s and Dunham’s theory depicted natural areas as circular zones. He used crime to describe the areas that he designated. Crime was concentrated in the central part of the city and eventually got better further away from the city center. This is the pattern that childhood obesity is showing. There is a significant area around Chicago and Waukegan that reflects this same idea. Not only does location affect criminal activity but it is also affecting the physical body and health of the people and most importantly the children. Although their theory may be dated, the idea and concepts are valid to understand the clustering of childhood obesity and some socioeconomic variables. Future Research Childhood Obesity is an important topic which may have long-term impacts on our society. This study only measures and examines a small amount of information. There are many other variables that could be further studied to understand all the underlying issues of childhood obesity and how socioeconomic status is correlated and related. In addition to what this study examined, crime and sedentary activity would be a great addition to this analysis. Also, further understanding where food deserts are located and fast 41 food locations are to study the relationship to access healthy and harmful foods and childhood obesity. The use of 2010 Census data would be interesting to utilize as well, it was not available at the time of the study, however a more comprehensive and complete version will be available later in 2010. A linear study of history verses present childhood obesity would be a great way to understand that changes in patterns of social and physical behavior of the people and children. In addition to using different methods and variables, a further study on the Chicago area and looking at other economic issues would be viable. According to William Julius Wilson, his theory that was discussed earlier is less about race but more about class. It would be interesting to incorporate his ideas about class and how inner city segregation might be affecting health, by examining the economy and racial profile of the area, housing values, and other characteristics of the neighborhoods in Chicago or other metropolitan areas. Conclusion After the results of our analysis, we can conclude that some socioeconomic variables play a role to affect the outcomes of childhood obesity. Out of the variables that were used in this study, low education was the strongest predictor of childhood obesity. It was then followed by race, and income. Childhood obesity and vulnerability is cluster around large metropolitan cities, and from our study mainly Chicago and Waukegan are the most affect. This would follow social disorganization theory which states that city centers bring more negative and unwanted results, such as crime and childhood obesity. 42 ACKNOWLEDGEMENTS I would like to extend my sincerest thank you to my advisor and mentor from the Geography department , Professor Devonee Harshburger for guiding my and providing me with an abundance of information and knowledge. Thank you for all the assistance with modeling out and interpreting the NHANES data. Your comments and insight was greatly appreciated. Your GIS skills are phenomenal and it was such an honor having you as an advisor, since it’s not even part of your job description. Thank you to you and your family for inviting me to your home to work on my thesis. I would like to extend my greatest gratitude to Dr. Wayne Thompson, who was my thesis advisor from the Sociology department. Thank you for sitting with me and working my data and SPSS and providing me with useful insights. Thank you for lending me some of your most treasured books. Your support throughout the last few years have been amazing and I can never thank you enough for all the assistance and knowledge you have taught me. In addition to my thesis advisors, I would like to thank my professors from Senior Seminar, Dr. Joy Mast for Geography and Earth Science Seminar and Dr. Stephen Lyng. Thank you for all the guidance and information. Your positive critiques and support has been greatly appreciated. I would also like to thank Dr. Julio Rivera for all the support through the last few years. Thank you for getting me initially interested in Geography. 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