Acculturation has been identified as a determinant of health behavior and outcome among ethnic minorities. The high prevalence of lifestyle-related chronic diseases and risk factors among Korean immigrants calls for a valid short acculturation scale to use in clinical practice and health research settings.

The aim of this study was to validate the psychometric properties of a short acculturation scale originally developed for Hispanics after translating the scale to Korean (SAS-K) to determine its suitability for use with Korean immigrants.

A self-administered questionnaire was completed by 143 Korean immigrants with Type 2 diabetes aged 30-80 years from a Korean community in Southern California. Confirmatory factor analysis, criterion validity, and internal reliability were utilized to evaluate the psychometric properties of the SAS-K.

Using a second-order confirmatory factor analysis, a 3-factor structure, χ(51) = 121.49, p < .001 (comparative fit index = .950, standardized root mean squared residual = .055, root mean square error of approximation = .099), was confirmed. The SAS-K was associated positively with length of residence, age of arrival, and English proficiency. Reliability for the total SAS-K was .93. Cronbach's alpha coefficients for each subscale of the SAS-K ranged from .80 (Ethnic Social Relations) to .95 (Media).

The 12-item, easy-to-use SAS-K showed satisfactory reliability and validity and, thus, is an appropriate instrument for measuring acculturation in Korean immigrants. The short nature and ease of administration of the SAS-K make it an ideal choice for healthcare providers and researchers to assess acculturation levels quickly and easily and to further the development and use of more culture-appropriate interventions.

Type 2 Diabetes Mellitus (T2DM) is a significant public health concern with high morbidity and mortality burden. Maladaptive food behaviors contribute to poor glycemic outcomes for persons with Type 2 Diabetes Mellitus (T2DM). Factors which may contribute to poor T2DM dietary behaviors include food addiction (FA; overconsumption to the point there are similar symptoms to substance use addiction) and impulsivity (lack of control in food consumption). FA and impulsivity behaviors can be reflected by differences in brain tissue integrity, but the relationships between FA, impulsivity, and brain tissue changes in persons with T2DM are unclear. To date, little is known about FA and impulsivity in association with A1c levels (indication of poor glycemic control) among T2DM patients. While studies indicate associations between brain injury and A1c levels in T2DM patients, it is also unclear if FA and brain injury can independently predict glycemic control in T2DM. An examination of the brain associated with these behaviors has not been assessed in persons with T2DM. The overarching purpose of this dissertation study is to offer valuable insights into the link between brain tissue integrity, food behaviors, and glycemic control in T2DM patients. Manuscript one compares the relationships between FA, impulsivity, and glycemic outcome (hemoglobin A1c) between 32 T2DM and 32 healthy patients between the ages 40-65 years. Participants completed the Yale Food Addiction Scale 2.0 (YFAS) and Barratt Impulsiveness Scale-11 (BIS) online questionnaires and A1c was measured with a fingerstick test. Between T2DM and healthy patients, there were no group differences in the prevalence of FA diagnosis, YFAS 2.0 scores, BIS-11 scores, or severity classification of FA diagnosis. There were positive correlations between two FA symptomatologies with higher A1c: food tolerance and food use in physically hazardous situations (r= 0.254, r= 0.417, P <0.05). There were no significant correlations between BIS-11 scores and A1c. In this study, two FA symptomatologies were linked to poor A1c suggesting that a subset of questions from YFAS 2.0 could provide clinicians insight into glycemic outcomes (A1c). This was the first study that investigated the associations between FA symptomatologies and A1c among T2DM patients and healthy controls. In manuscript two, using diffusion tensor imaging data, mean diffusivity (MD) values were calculated, and region-of-interest analyses were performed on various brain areas to examine correlations between brain tissue integrity (measured by MD values) and YFAS 2.0 and BIS scores (partial correlations; covariates, age, and sex). Twenty-one T2DM participants between the ages 40-65 years completed brain magnetic resonance imaging (MRI) scans. There were significant correlations between tissue integrity and YFAS 2.0 scores in brain regions regulating executive decision-making (cortices, precuneus, temporal); memory -visual or auditory (occipital, supramarginal); motor function (putamen); and emotion (cingulum) functions in T2DM patients. While there were no associations between BIS-11 scores and brain tissue integrity, there is now neuroimaging evidence of specific impaired brain sites that mediate FA symptomatologies among T2DM patients in this sample. Manuscript three determined which of the following were independent predictors of A1c status: food tolerance and food use during physically hazardous situations FA symptomatologies (found in manuscript one), and areas of brain damage (that are linked to A1c) in the following regions: areas mediating cognition/executive decision-making (frontal middle-right, frontal medial orbital -right) and emotion (cingulate). Among 32 T2DM patients, only tissue changes in the right medial orbitofrontal cortices (OFC) were an independent predictor of glycemic status, and not the two FA symptomatologies or the other brain regions. Findings from manuscript two and three regarding injury to brain areas regulating cognition (frontal cortices) further corroborate past structural neuroimaging studies that T2DM patients have brain injury in the frontal cortices affecting their decision-making. The dissertation identifies several interventions with the potential to promote neurogenesis or neuroprotection in areas of brain injury (e.g., cognitive brain training, neurofeedback, stem cell therapies, and nutritional supplementation). This dissertation contributes to T2DM research by shedding light on the crucial role of brain regions in regulating food behaviors and, subsequently, managing A1c. This understanding shifts the focus of interventions from solely addressing physiological or behavioral aspects of T2DM to incorporating brain-based interventions that can improve glycemic outcomes. By highlighting these potential interventions, the dissertation opens new avenues for research and development in T2DM management and ultimately, improved care for T2DM patients.

The purpose of this study is to examine the relationship between negative emotions and bio-behavioral risk factors among Korean immigrants at risk for type 2 diabetes (T2DM).

Data were collected from 148 Korean immigrant adults who are “at risk” for T2DM as defined by having family history of T2DM in first degree relatives, body mass index greater than 23, or history of gestational diabetes in women. Participants completed questionnaires and underwent biological measures. Negative emotions included feeling nervous, hopeless, restless, anxious, and stressed as well as depressive symptoms.

High percentages of participants had T2DM risk factors including overweight, greater than normal waist to hip ratio, and blood glucose readings that are indicative of T2DM. Feeling stressed was the most commonly reported negative emotion (66%), followed by feeling anxious (51%), restless (38%), nervous (30%), and hopeless (13%). Experience of negative emotions was significantly related to behavioral risk factors; higher levels of experiencing negative emotions were related to increased soda intake and a decreased likelihood of doing at least 10 minutes of moderate exercise. Stress and anxiety were each negatively related to moderate exercise and depressive symptoms were negatively related to both moderate and vigorous exercise. No significant relationship was found between negative emotions and biological risk factors.

Findings suggest that negative emotions, individually and taken together, may be related to T2DM risk behaviors in high-risk Korean immigrants. Behavioral interventions to prevent T2DM in this population should consider assessing and addressing negative emotions.

To investigate gender and ethnic type 2 diabetes (DM) prevalences among California Asian subgroups versus other ethnic groups and if risk factors explain these differences.

We identified the prevalence of DM and associated risk factors, stratified by gender, among Chinese, Filipino, South Asian, Japanese, Korean, Vietnamese, Mexican, Other Hispanic, African American, Caucasian, and Native American adults in a large survey conducted in 2009 (n=46,091, projected n= 26.6 mil).

The highest age-adjusted DM prevalence was seen in Native Americans (32.4%), Filipinos (15.8%), and Japanese (11.8%) among men and in Native Americans (16.0%) and African Americans (13.3%) among women. Caucasian and Mexican men had higher DM prevalences than women. Age and risk factor-adjusted logistic regression showed DM more likely (relative to Caucasians) among women in Koreans (OR=4.6, p<0.01), Native Americans (OR=3.0, p<0.01), and Other Hispanics (OR 2.9, p<0.01) and among men in Filipinos (OR=7.0, p<0.01), South Asians (OR=4.7, p<0.01), and Native Americans (OR=4.7, p<0.01). No specific risk factors accounted for the gender differences.

Ethnic and gender differences in DM prevalence persist, even after adjusting for lifestyle and other risk factors; prevalence is high among certain Asian American subgroups. Different diabetes prevention approaches may be needed across ethnic/gender groups.

Asian subgroup-specific information on type 2 diabetes mellitus (DM) is scarce. Using the California Health Interview Survey 2007 data, we examined Chinese, Korean, Japanese, Filipinos, and Vietnamese adults (n = 3,688) and Caucasian adults (n = 33,981) for the prevalence of DM and risk factors. The age-adjusted prevalence of DM was the highest among Filipinos (8.05%) followed by Japanese (7.07%), Vietnamese (7.03%), and Koreans (6.3%). Chinese (5.93%) was the only Asian group studied whose prevalence was lower than Caucasians (5.94%). From multiple logistic regression, after adjusting for risk factors, Japanese had the highest likelihood of DM (OR = 1.75, CI = [1.12-2.73], P < 0.05), followed by Filipinos (1.66, [1.13-2.43], P < 0.01), and Koreans (1.59, [1.00-2.52], P < 0.05), relative to Caucasians. Our results suggest that even after accounting for lifestyle and other risk factor differences between Caucasians and key Asian subgroups in California, Japanese, Filipinos, and Koreans have a 1.6-1.75 greater likelihood of DM compared to Caucasians.