Employment is an important occupation for young adults, including those with disabilities such as autism spectrum disorder (ASD). Secure employment is associated with positive self-esteem and higher quality of life for people with ASD. People with ASD, however, have generally poor employment outcomes. The development of effective school supports is needed to prepare youth with ASD for the transition from school to employment. This dissertation represents a mixed methods study to (1) understand how and what school personnel think about when preparing youth with ASD for employment, and (2) explore how the personal and contextual factors (such as youth’s functioning and academic performance, family background, and parent participation in the youth’s education) predict post-school employment outcomes for students with ASD. To address the first research aim, 20 school personnel were interviewed. Based on the interview data, we developed a conceptual model describing how school personnel provided employment preparation for this population. The model highlights how school personnel view the student’s personal and contextual factors as equally important and indivisible for employment success. As school personnel prepare youth for employment, they also consider how to support the youth to create a meaningful life in the community, including how and where youth will live, remain safe, maintain recreation and exercise routines, and develop social connections. The findings of the first study served as a theoretical basis of the second study and were used to identify contextual factors included in the research aims and to develop a statistical model. To address the second research question, a secondary analysis was conducted with a nationally representative database. By adopting the structural equation modeling (SEM) analysis, we found that school-based transition supports and academic performance were important mediators between parental participation in youth with ASD’s education and employment outcomes. The pathways that predicted employment outcomes for youth with ASD were different for youth with different levels of daily functioning skills. This analysis was the first to identify the important role of school supports in post-school employment outcomes for youth with ASD. The findings of these two studies indicate that preparing youth with ASD for the transition to employment is a highly individualized and contextualized process that involves collaborations among school, family, and the community. This research illustrates the importance of environmental factors in employment outcomes for this population. Whereas current interventions and research often focus on youth’s vocational skills, it may be equally or more important to consider environmental barriers and supports that may be amenable to change to meet youth’s employment needs. / 2021-09-28T00:00:00Z

Premenstrual syndrome (PMS) is characterized by the presence of physical and psychological symptoms restricted to the late luteal phase of the menstrual cycle and associated with substantial impairment in life activities. In the U.S. about 8 to 15% of women of reproductive age suffer from PMS. Many micronutrients are potentially involved in the development of this disorder due to their role in the synthesis of neurotransmitters and hormones or in their regulation, but few previous studies have evaluated the effects of micronutrients on PMS. The first study examined the association between B vitamin intakes, and PMS development among women participating in the Nurses' Health Study 2 (NHS2). We found that high thiamin and high riboflavin intake from food sources were associated with lower risk of PMS. There were not significant associations between niacin, vitamin B6, folate, and vitamin B12 dietary intake and incident PMS. Intakes of B vitamins from supplements were not associated with lower risk of PMS. The second study evaluated the association between selected mineral intakes and PMS development in the NHS2. In this study, high iron intakes were associated with lower risk of PMS. Although there was no association between zinc and PMS risk, high intake of zinc relative to copper was associated with lower risk of PMS. There were no associations between of magnesium, copper, and manganese intakes and PMS. We observed a significantly higher risk of PMS in women with high intakes of potassium from food sources. The third study focused on the association between dietary intakes of B vitamins, zinc, magnesium, iron, potassium, and sodium and some biomarkers and PMS prevalence among younger women. In this study, we found an association between zinc intake and lower prevalence of PMS. Each 1 mg/d increase in vitamin B6 from foods was associated with a lower PMS symptom score. Blood magnesium levels were higher in women with PMS compared to women without PMS. We observed that intakes of some micronutrients were associated with lower risk of PMS, but further studies should be conducted. This dissertation contributes to the research on modifiable risk factors for PMS.

STUDY 1 Aim: To compare the effects of Roux-en-Y gastric bypass (RYGB) and laparoscopic adjustable gastric banding (LAGB) on changes in bone mineral density (BMD), weight loss and blood biomarkers related to bone turnover, hormonal, and nutrient status. Subjects: Nine bariatric surgery patients. Methods: Patients had a DXA bone scan and fasting blood draw at baseline, three, and six months following surgery. Results: RYGB patients had greater weight loss vs. LAGB at both three (mean loss: 19 vs. 9%) and six months (26 vs. 11%), p<0.01. RYGB patients lost an average of 7% hip BMD at six months. Hip BMD loss at six months was correlated to decreased leptin (r=0.88) and increased adiponectin (r=-0.82), p<0.05. Bone turnover was indicated by elevated serum bone biomarkers after surgery. Conclusions: Research with larger sample sizes is warranted to better evaluate potential implications for late-life osteoporosis risk following bariatric surgery. STUDY 2 Aim: To determine repeatability for IMAT and muscle density, to evaluate the distribution of foreleg muscle and fat indices measured by pQCT and to determine predictors of muscle density and type-2 diabetes risk. Subjects: 82 women with varying BMI and physical activity levels. Methods: Subjects had DXA and pQCT bone scans, a fasting blood draw, and completed a 4-day physical activity record. Results: Fat and muscle distribution in the foreleg was highly correlated to total and central body adiposity. The pQCT device reliably measured muscle density (CV=0.8%), thus justifying use as surrogates for IMAT. Muscle density was positively related to physical activity (r=0.29; p<0.05) and negatively associated with markers of fat distribution and risk for type-2 diabetes [HOMA-IR (r=-0.44, p<0.01)]. Conclusions: Further research is necessary to determine whether specific fat or muscle depots can be targeted through exercise training to help with the prevention and treatment of obesity or type-2 diabetes. / Ph. D.

Background: Diabetes mellitus and vascular diseases have a significant impact on the eye. / Aim: To determine the prevalence, risk factors, and racial/ethnic differences of major eye conditions, particularly retinal conditions, associated with diabetes and vascular diseases. / Scope: To date, the majority of studies have examined the association of retinal vascular calibre and diabetes in predominantly white Caucasian populations. Further elucidation of ethnic differences in effects of hyperglycaemia on early microvascular disease is relevant, particularly amongst Asians where diabetes is likely to see the largest increase in prevalence over the next decade. We therefore examined these findings from three Asian population-based studies, the Singapore Malay Eye Study (n=3280), Singapore Prospective Cohort Study and Singapore Cardiovascular Cohort Study 2 (n=3748). / Results: The prevalence of diabetic retinopathy in the Singapore Malay Eye Study was 35%, and associated with longer duration of diabetes, poorer glycemic and blood pressure control. More importantly, 9.0% had vision-threatening retinopathy, and retinopathy was found in 6.0% of people without diabetes. Retinal vascular calibre changes were incriminated in diseases such as diabetes and hypertension, independent of traditional cardiovascular risk factors. Wider venular calibre was independently associated with early age-related macular degeneration. We also found a novel association between peripheral artery disease and glaucoma, stronger in persons with diabetes, independent of vascular risk factors, supporting the vascular theory of glaucoma. / Implications: Subtle changes in retina, including retinal vascular calibre may be early markers of widespread microvascular changes in diabetes, resulting from chronic hyperglycaemia and other pathogenic processes. These results will have broad implications for understanding the impact of both microvascular and macrovascular complications of diabetes in the Asia Pacific region and targeting relevant therapeutic interventions.