Weight Stigma in Relation to Hair Cortisol and Binge Eating in Obese Asian-Americans

Purpose: The purpose of this study is to examine the relationships between weight stigma, level of acculturation, hair cortisol levels, and binge eating among overweight and obese Asian-Americans.  Obesity is an important public health concern for Asian-Americans in the United States (Jih et al., 2014).  Many children and adults face weight stigmatization as a result of being overweight or obese (Levy & Pilver, 2012).  Weight stigma can be defined as individuals experiencing verbal or physical abuse secondary to being overweight or obese (Puhl & Heuer, 2011).  Weight stigma may be considered a stressor and cause cortisol levels to increase by triggering hypothalamic-pituitary-adrenocortical (HPA) axis activation, which can lead to adverse health outcomes such as a high-risk for developing type 2 diabetes and poor glycemic control (Tsenkova et al., 2011).  Weight stigma can also contribute to binge eating and the development of obesity (Jackson, Beeken, & Wardle, 2014; Wu & Liu, 2015 ).  Acculturation is a process in which members of one cultural group adopt the beliefs and behaviors of another group (Bharmal et al., 2014).  The level of acculturation for Asian-Americans may be related to their body image perception as well as the experience of weight stigma (Guan, Lee, & Cole, 2012).  

Methods: A cross-sectional design with a convenience sample will be used.  The sample population will include overweight and obese (BMI >23 kg/m²) Asian-Americans (Taiwan, Hong Kong, and China) adults (≥ 21 years of age) living in North Carolina, United States.  Participants will be recruited from Chapel Hill, Durham, and Cary, North Carolina starting in March 2016.  A total of 161 participants will be needed in order to reach a power of .80 with the effect size of 0.12 and α value of 0.05 for the study (Himmelstein et al., 2015).  A hair sample, demographic data, height and weight, calculated body mass index and five questionnaires measuring the weight stigma experience, binge eating, the level of acculturation for Asians, the level of perceived racial discrimination for Asians,  and levels of perceived stress will be collected.  Hair cortisol will be analyzed by using a high-sensitivity enzyme immunoassay (EIA) kit at a Biobehavioral Laboratory in Chapel Hill, North Carolina,  United States (Meyer, Novak, Hamel, & Rosenberg, 2014).  Participants will be recruited by posting ads on the electronic billboard of three Asian associations’ websites.  Potential participants will contact the investigator by telephone and will be screened.  Eligible individuals will be scheduled for a group data collection at a church.  The protocol for this proposed study will be reviewed and approved by the Institutional Review Board at the University of North Carolina at Chapel Hill.

Results: The study data will be analyzed using SAS 9.3 (SAS Institute Inc., 2014).  Descriptive statistics will be used to provide the mean and standard deviation.  Group differences will be examined by independent t-tests. Pearson correlation analysis will be used to determine the relationships among all variables.  Multiple regression analyses will be used to determine the associations between the experiences of weight stigma (independent variable) and hair cortisol levels and binge eating (dependent variables) after statistically controlling for the level of perceived racial discrimination for Asians and the level of perceived stress (control variables).  

Conclusion: This will be the first study to explore the relationship of weight stigma, acculturation levels, cortisol levels, and binge eating simultaneously for overweight and obese Asian-Americans.  If this relationship is found, it could have a major impact on future interventions for Asian-Americans who experience weight stigma and who do the stigmatizing.  The results from this proposal could help us to build a theory-based intervention to decrease weight stigma.  Once a future intervention is tested for feasibility and efficacy, the intervention could be shared in Asian-American community centers.  Our proposal addresses a significant health problem in Asian-Americans.  The development of interventions to improve the lives of overweight and obese Asian-Americans is an important public health goal.