Running Head: COMPONENTS OF CHILDHOOD OBESITY 1 Non-Genetic Components of Childhood Obesity

Childhood obesity is causing rising concern for health officials throughout America as well as other developed countries. The rates of childhood obesity are leveling off or rising in many cases depending on the sample and subgroups of the samples such as gender and race. It is important to stop the rise of childhood obesity by finding possible causes and providing treatment. Obesity is linked to countless immediate and long term health problems including heart problems, sleep apnea, diabetes, and even certain cancers. Obesity is correlated not only to other health risks but also developmental problems such as low self-esteem and poor academic performance. In this review, the links between obesity and stress, socio-economic status, diet, and physical activity were explored. Through this research it is more clear how stress, socioeconomic status, diet and physical activity impact childhood obesity. It is important to note that the results of these studies find varying results. There are many other interactions and interplay between these factors that contribute to the causes of childhood obesity. COMPONENTS OF CHILDHOOD OBESITY 3 Non-Genetic Components of Childhood Obesity Rates of childhood obesity have been leveling off or rising in many developed countries. In the United States the rates of childhood obesity has more than tripled since 1971. Childhood obesity is linked to countless immediate and long term health problems including heart problems, sleep apnea, diabetes, and even certain cancers. Obesity is correlated not only to other health risks but also developmental problems such as low self-esteem and poor academic performance. Now childhood obesity is the number one health concern according the parents and the American Heart Association (2016). This paper aims to explore the research on the possible non-genetic causes of childhood obesity such as stress, socio-economic status, diet, and physical activity. If personal stress is found to increase the risk of obesity in children it is possible that parental stress would impact childhood obesity because of the integral role parents play in the life of their children. Things such as maternal depression, conflicts between parents, family disruption, and house moves can create a sizable amount of disruption and stress for a child (Giles et al, 2013). Parental stress could impact the baby through increasing their stress level or by altering the adults’ parenting style. In addition, non-secure parenting styles may create stressful home environments and interactions between the child and parents (Stenhammar et al, 2010). Non-secure attachments include avoidantly attached and ambivalent attached. Mothers with these attachments with their child seem to be less engaged and less responsive to the needs of their child (Larsen & Buss, 2014). The child can react by becoming upset or becoming emotionally distant. Research has also shown that sexually abused individual’s coping styles and eating behaviors may have changed to deal with their abuse. Some researchers have even found that children use overweight as a defense mechanism against abuse (Veldwijk, 2012). COMPONENTS OF CHILDHOOD OBESITY 4 Stress during childhood activates the HPA axis in children which releases cortisol and impacts both the stress system and eating behaviors (Koch et al, 2008). Cortisol is released in the presence of a stressor. Cortisol which is released when an individual is stressed has been correlated with obesity and an increase in visceral fat. The cortisol awakening response is defined as an increase of cortisol secretion within 60 minutes of waking up. This increase of cortisol is associated with chronic stress (Van Jaarsveld et al, 2009). Visceral fat has been shown in previous research to be associated with biological and behavioral responses to stress such as the activation of the HPA axis, high levels of cortisol, increased appetite and eating fatty sugary foods (Donoho et al 2011). There are also links with increased levels of cortisol and activity in the HPA axis with children who have been abused (Veldwijk, 2012). In this review the links between obesity and stress, socio-economic status, diet, and physical activity will be explored. Through this it will give more insight into possible causes of the epidemic and possibly help guide treatments. Links between stress and childhood obesity In this section the correlations between stress and childhood obesity are explored. This is a complex area of research with conflicting results. Different researchers have found mixed results on the associations between perceived stress and childhood obesity. For example one study have shown that there were links between long term parenting stressors and not short term stressors (Kosh et al, 2008) and yet another study found that there was no association between parenting stressors and childhood obesity (Ohookana et al, 2016). Also, one study found increase in obesity only in girls in their study (Dockray et al, 2008). It is hypothesized that stress impacts obesity through behavioral mechanisms and eating unhealthy foods or not exercising, emotional mechanisms like comfort eating, and hormonal mechanisms such as the COMPONENTS OF CHILDHOOD OBESITY 5 HPA axis and cortisol (Van Jaarsveld et al, 2009). In addition, some researchers believe there are sex differences for how stress impacts the risk of obesity. They believe that stress is correlated with obesity because women seek fatty and sugary foods when stressed. However for males the increase of cortisol as a result causes an increase in food intake (Yin et al, 2005). Previous research has found links between traumatic experiences, psychological stress, family stress, cortisol levels, and abuse. Traumatic experiences such as sexual, emotional, and physical abuse can have lasting consequences on children. These traumatic experiences have mental and emotional consequences, increase stress levels, and alter coping mechanisms. Extreme levels of stress even just one occurrence has a correlation with obesity in children. Physical, sexual and emotional abuse are all significantly correlated with childhood obesity. The risk of obesity is increased as well in cases of more than one abuse. 51 percent of obese children were victims of multiple forms abuse compared to only 23 percent were normal weight with multiple forms of abuse. (Veldwijk et al, 2012). Isohookana et al (2016) found that traumatic experience such as sexual abuse can contribute to obesity in females. This study looked at 300 girls and 208 boys who were admitted for acute psychiatric hospitalization. It was found that girls who were sexually abused were 2.6 times more likely to be overweight compared to girls who did not experience a sexual abuse. While this was found for girls there was no correlation between obesity and traumatic childhood experiences. Individual stressors and personal stress have been found to impact childhood obesity (Lohman et al, 2009 & Yin et al, 2005) Lohman et al (2009) suggest that the stressors may act on biology by activating the hypothalamus and increasing eating behavior or it may also be biological and stress makes it more likely for individuals to engage in unhealthy eating and COMPONENTS OF CHILDHOOD OBESITY 6 decreased physical activity. Yin et al (2005) was interested in how stress impacted obesity in children and looked not only at BMI but also sum of skin folds to measure general adiposity and waist circumference to measure central adiposity. It was hypothesized that stress would influence central adiposity more; however, it was found that stress predicted central and general adiposity. One interesting study measured stress of children by the number of house moves. It was found that house moves cause a prolonged physiological stress response that was found to be a statistically significant predictor to childhood obesity (Giles et al, 2013). In addition Donoho et al (2010) found that school stress in young girls was significantly correlated with visceral fat when examining what personal stressors impacted obesity in children. They measured school stress by arguing with a teacher, amount of big tests or projects, and fights in school. Conflicting results found that perceived stress was not correlated with increases in waist size or increases BMI; however, BMI and larger waist size were significantly higher for the adolescents that had higher stress. The fact that perceived stress was not correlated with increases in waist size and BMI suggest that stress does not impact the rate at which the adolescents are gaining weight. But the fact that BMI and waist size was significantly higher in adolescents that have higher stress suggests that ongoing chronic stress is related to childhood obesity (Van Jaarsveld et al, 2009). Because parents and family are important in the lives of young children and adolescents many researchers expect to see correlations between parental stress and childhood obesity (Lohman et al, 2009) Parental divorce, unemployment, lack of social support, and serious life events have all been suggested to cause significant levels of stress in families and children making them points of interest when examining the links between family stress and childhood obesity(Watts et al, 2008, Stenhammar et al 2016, Koch et al, 2008). Serious life events such as COMPONENTS OF CHILDHOOD OBESITY 7 divorce, unemployment, death were assumed to cause stress and was found to increase the rate of childhood obesity (odds ratio of 1.42). The measure of parenting stress was not related to childhood obesity when the stress was short term but long term stress was positively correlated with obesity. Even when adjusted for parent obesity the relationship was still strong between parenting stress and child obesity. The more stressful situation that the family has the percentage of childhood obesity increases (Koch et al, 2008). Watts et al (2013) and Stenhammar et al (2016)fou