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Age-related macular degeneration (AMD) is a chronic, irreversible disease that robs individuals of vision, quality of life, and independence. It is the leading cause of blindness in industrialized countries. Sleep-disordered breathing (SDB) is a condition characterized by repeated episodes of apnea and/or hypopnea, insomnia, short sleep duration, and/or sleep disturbances (snoring, gasping, etc.). Because SDB has been shown to cause chronic hypoxia resulting in oxidative stress on the retina, it has been proposed that SDB may be associated with AMD. Based on the life course theory of chronic disease, this quantitative, cross-sectional study used data from the 2005-2008 National Health and Nutrition Examination Survey to study whether there was an association between SDB and AMD, including neovascular AMD and geographic atrophy in adults 40 years and older. Descriptive statistics and logistic regression analyses were used. The results suggest that AMD is associated with diagnosed sleep disorders, including sleep apnea and insomnia, as well as sleep apnea symptoms of gasping snoring, snorting, and stopping breathing. The findings of this study highlight the importance of diagnostic screening and therapeutic intervention to treat SDB. Early diagnosis and therapy for SDB could address not only the comorbidities associated with SDB, but could also prevent or slow the progression of AMD. In turn, this would yield lower rates of vision loss, reduced comorbidities associated with vision loss, and reduced impact of AMD on the health care system and social and financial costs to society.

Mixed results have been reported when body size is used to estimate the effect of health and nutritional status on worker productivity. This dissertation offers an alternative hypothesis that body composition rather than body size is responsible for the effects of health and nutritional status on worker productivity. Body fat is responsible for the poor health associated with obesity. Lean body mass is responsible for the superior performance associated with physical fitness. Studies using body size alone cannot distinguish the combined, but opposite effects, of body fat and lean body mass. A method is provided here that overcomes the lack of data for body composition. The clinical information available in the Third National Health and Nutrition Examination Survey 1988-94 (NHANES III) is used to estimate body composition for the survey participants in the National Longitudinal Survey of Youth (NLSY 1979). The inclusion of estimated body composition in the estimated wage equation shows that the effect of lean body mass on the wage rate is positive while the effect of body fat is negative. Estimated body composition is then used to examine the role of physical differences in the gender wage gap. The decomposition of the gender wage gap shows that most of the previously unexplained differences in wages between men and women can be attributed to the gender differences in body composition. The explanatory power of estimated body composition rises significantly with occupational physical strength requirements. This result suggests that estimated body composition is capturing occupational requirements previously omitted from the past studies. The findings presented in this dissertation indicate that body composition plays an important, though previously unidentified, role on wage determination. It is clear that capital investments in body composition yield economic dividends by impacting hourly wages of workers. Empirical studies that do not address differences in body composition risk obtaining biased results. Future public health policies should take into consideration the combined but opposite effects of body fat and lean body mass. It is not body size alone, but the compositional makeup of the human body, that public health policies may need to address.

Background: Contribution of dietary sources to vitamin D status is not clearly known. Some studies have shown that dietary intake of certain vitamin D rich foods had a significant positive influence on serum 25-hydroxyvitamin D [25(OH)D] concentrations, whereas other studies have shown no effect. Although sunlight exposure is a major source of circulating serum 25(OH)D, children and adolescents have been advised on the dangers of sun exposure. Diet may therefore be an important contributor of circulating serum 25(OH)D in absence of or reduced sunlight exposure. Objective: The aim of this study was to determine whether serum 25(OH)D concentrations were associated with any specific dietary patterns in US children and adolescents using assay-adjusted serum 25(OH)D data from National Health and Nutrition Examination Survey (NHANES) 2003-2004 and 2005-2006. Methods: Data from 2 cycles of the NHANES 2003-2004 and 2005-2006 for individuals aged 2 to ≤19 y, were used to study the association between dietary patterns and serum 25(OH)D. Dietary patterns were established using factor analysis based on food-frequency questionnaire data. Eigenvalues and Scree plot were used to derive 2 major principal factors. They were labeled as High Fat Low Vegetable (HFLV) and Prudent dietary patterns. Results: Serum 25(OH)D was significantly lower in HFLV dietary pattern group compared to Prudent dietary pattern group (25.1 vs 27.0 ng/mL; P=0.001). The highest serum 25(OH)D concentrations for all subjects were in the low-intake HFLV group or medium and high-intake Prudent groups (P=0.003 and P=0.012, respectively). In multivariate adjusted analysis, children with higher Prudent dietary contribution scores to overall diet showed a significant positive relation with serum 25(OH)D (β=62.01, P=0.016). When data were stratified by sex, a significant positive relation was observed in girls who consumed the Prudent diet (β=86.34, P=0.014) and a significant negative relation was observed in girls who consumed the HFLV diet (β=-84.32, P=0.022). Conclusion: Overall, serum 25(OH)D concentrations were associated with Prudent dietary pattern but not with HFLV dietary pattern in US children and adolescents. When stratified by sex, the relation between dietary patterns and serum 25(OH)D was confined to only girls. Children consuming HFLV pattern diet may benefit from vitamin D supplementation and sunlight exposure (outdoor activities), and should be encouraged to consume more vitamin D fortified foods.

This research uses data from the 2003-2006 National Health and Nutrition Examination Survey (NHANES) to determine dietary and other factors associated with serum 25(OH)-Vitamin D concentration for 5,474 adults age 20 years and older. After multivariate adjustment, we found that serum 25(OH)-Vitamin D concentration was positively associated with diets high in fruits, vegetables, and lean meats, while diets high in processed foods and high-fat meats were inversely associated with vitamin D level. Serum 25(OH)-Vitamin D concentration was also signifi-cantly associated with age, gender, race/ethnicity, BMI, physical activity, supplementation, and the season of survey administration. Self-reported cardiovascular and kidney disease were significantly associated with serum 25 (OH)-Vitamin D concentration after adjustment for significant confounders.

ABSTRACT Background: Prediabetes is a precursor condition to type 2 diabetes mellitus. Previous research and clinical trials have shown that the onset of type 2 diabetes could be delayed or prevented through structured life style modifications such as dietary changes, modest weight loss and moderate-intensity exercise. This study examines U.S adults of different ethnicities that include non-Hispanic white, non-Hispanic black and Mexican Americans and whether their awareness of diabetes risk is associated with their participation in diabetes risk reduction behavior, a combination of physical activity, weight control and fat/calories intake. Methods: The 2007-2008 National Health and Nutrition Examination Survey, NHANES, was used to conduct a cross-sectional study of 4083 U.S. adults who were 20 years old and above and were aware of their diabetes risk. The association between the awareness of one’s diabetes risk and the adoption of diabetes risk reduction behavior were examined in present of other risk factors such as age, gender, ethnicity, education, annual family income, BMI, hypertension, mean systolic blood pressure, mean diastolic blood pressure, total cholesterol, LDL, HDL and triglyceride levels. Males and females were examined separately for all analyses performed. Cross tabulation was conducted and p-values were calculated by the Pearson’s chi-square test for the categorical variables which include gender, ethnicity, education, annual family income, adiposity and hypertension. One Way ANOVA and Tukey post hoc tests were conducted for the continuous variables which include age, mean systolic blood pressure, mean diastolic blood pressure, total cholesterol, LDL, HDL and triglyceride levels. Univariate and multivariate analyses were performed to determine the association between the main independent variable, awareness of one’s diabetes risk, and the dependent variable, adoption of diabetes risk reduction behavior, controlling for other risk factors. A p-value of <0.05 and 95% confidence intervals were used to determine statistical significance throughout all analyses performed. Results: After controlling for age, gender, race, education, annual family income, BMI, hypertension, mean systolic blood pressure, mean diastolic blood pressure, total cholesterol, LDL, HDL, and triglycerides, results from the multivariate analysis showed that subjects who were aware of their diabetes risk were more likely to adopt diabetes risk reduction behavior (OR= 1,734, 95 % CI=1.217-2.470). Females and non-Hispanic blacks, who were aware of their diabetes risk, were also more likely to adopt diabetes risk reduction behavior compared to males, non-Hispanic whites and Mexican Americans. An increase in the levels of education, annual family income and BMI was also associated with the adoption of diabetes risk reduction behavior. Stratification according to gender and ethnicity, showed that Mexican American males and females were more likely to engage in diabetes risk reduction behavior compared to non-Hispanic whites and non-Hispanic blacks (Mexican American males: OR: 2.496, CI: 0.792-7.868; Mexican American females: OR: 2.830, CI: 0.917-8.736). Conclusion: This study provides useful insights for health care providers and public health professionals who are developing health promotion and prevention interventions to address pre diabetes before it develops into type 2 diabetes. This study also allows the development of tailored interventions for specific genders and ethnic groups that are at risk. Results of this study indicate that Mexican Americans and females (in general) are more likely to adopt diabetes risk reduction behavior. Therefore, physicians and health care providers should develop culturally, linguistically and gender- specific education materials and programs for this particular gender and ethnic group. This in turn, may reduce the overall increasing prevalence of diabetes, reduce racial and gender disparities and may have a positive impact on the overall health of the U.S. population.

Background: Paraben exposure occurs everyday to most people unknowingly. Parabens are present in most personal care products in varying amounts. Presently, parabens are not listed as endocrine disruptors; however, some research has shown parabens associated with decreases in thyroid hormone levels. The chemical and adsorption mechanism for parabens in association with thyroid hormones is not well understood. Determining whether parabens are associated with a change in thyroid hormone levels can help reduce the incidence of possible adverse health effects with exposure to parabens. Methodology: The selected study variables were analyzed using SAS version 9.2. Data were obtained from the 2007-2008 National Health and Nutrition Examination Survey (NHANES). Analyses were performed separately for adolescent females (12-19) and adult females (20+). Weighted means were performed for the main independent and dependent variables of interest stratified by race/ethnicity groups and by smoking status. Independent samples t-test and ANOVA was used to test significance of differences of weighted means. Weighted bivariate linear regression was performed for each dependent variable (Thyroid Stimulating Hormone [TSH], Triiodothyronine [T3], and Thyroxine [T4]) regressed on butylparaben. Weighted multiple linear regressions were performed and parameter estimates with 95% confidence intervals were used to ascertain the measure of effect. Separate regression models stratified by age group (adolescent vs. adult) were ran for each dependent variable (TSH, T3, and T4) regressed on butylparaben level and covariates, race/ethnicity and smoking status (ever smoked). Results: Weighted bivariate linear regression showed that among adult females, for each ng/ml increase in butylparaben, there was a -1.07 decrease in ng/dL T3 (p Weighted multiple linear regression showed higher butylparaben levels among adult females were associated with 0.12 ug/dL lower than average T4 levels (p Conclusion: While parabens are currently not considered endocrine disruptors, the human metabolism of and effects from exposure to parabens are not well understood. Results from this study showing decreased levels of some thyroid hormone levels (TSH, T3, and T4) associated with increased levels of butylparaben was found, as well as differences in thyroid hormone levels among racial/ethnic groups. Although not many human studies have found significant results, 10 some rodent studies have found butylparaben associations with thyroid hormone changes.4, 6, 19, 54 The results of this study indicating no statistically significant association between butylparaben and decreases in thyroid hormone levels are consistent with results of some rodent studies.7, 8, 54, 55 In light of these findings, additional human studies with paraben exposure and thyroid hormone levels are needed to increase knowledge of the mechanism and effect of parabens in the human body.

Background: Contribution of dietary sources to vitamin D status is not clearly known. Some studies have shown that dietary intake of certain vitamin D rich foods had a significant positive influence on serum 25-hydroxyvitamin D [25(OH)D] concentrations, whereas other studies have shown no effect. Although sunlight exposure is a major source of circulating serum 25(OH)D, children and adolescents have been advised on the dangers of sun exposure. Diet may therefore be an important contributor of circulating serum 25(OH)D in absence of or reduced sunlight exposure. Objective: The aim of this study was to determine whether serum 25(OH)D concentrations were associated with any specific dietary patterns in US children and adolescents using assay-adjusted serum 25(OH)D data from National Health and Nutrition Examination Survey (NHANES) 2003-2004 and 2005-2006. Methods: Data from 2 cycles of the NHANES 2003-2004 and 2005-2006 for individuals aged 2 to ≤19 y, were used to study the association between dietary patterns and serum 25(OH)D. Dietary patterns were established using factor analysis based on food-frequency questionnaire data. Eigenvalues and Scree plot were used to derive 2 major principal factors. They were labeled as High Fat Low Vegetable (HFLV) and Prudent dietary patterns. Results: Serum 25(OH)D was significantly lower in HFLV dietary pattern group compared to Prudent dietary pattern group (25.1 vs 27.0 ng/mL; P=0.001). The highest serum 25(OH)D concentrations for all subjects were in the low-intake HFLV group or medium and high-intake Prudent groups (P=0.003 and P=0.012, respectively). In multivariate adjusted analysis, children with higher Prudent dietary contribution scores to overall diet showed a significant positive relation with serum 25(OH)D (β=62.01, P=0.016). When data were stratified by sex, a significant positive relation was observed in girls who consumed the Prudent diet (β=86.34, P=0.014) and a significant negative relation was observed in girls who consumed the HFLV diet (β=-84.32, P=0.022). Conclusion: Overall, serum 25(OH)D concentrations were associated with Prudent dietary pattern but not with HFLV dietary pattern in US children and adolescents. When stratified by sex, the relation between dietary patterns and serum 25(OH)D was confined to only girls. Children consuming HFLV pattern diet may benefit from vitamin D supplementation and sunlight exposure (outdoor activities), and should be encouraged to consume more vitamin D fortified foods.

Background: Risk factors for childhood obesity include unhealthy diet, physical inactivity and lack of knowledge about nutrition and health. The purpose of this study was to investigate the potential associations between socio-economic determinants, dietary intake, self-perception, weight control behaviours and childhood overweight and obesity.   Methods: Cross-sectional data from the National Health and Nutrition Examination Survey 2013-2014 in the United States was examined. The sample included participants age 2-19, whose measured BMI indicated ‘normal weight’ or ‘overweight or obese’. The relationship between socio-economic determinants and dietary intake with BMI status was analysed using multiple logistic regression. Differences in self-perception of weight and associated weight control behaviours in relation to BMI status were examined in a sub-sample of youth age 8-15.   Results: School age (6-11 years) and adolescence (12-19 years); Mexican American, Other Hispanic and Black ethnicity; and household size of maximum two persons were significantly associated with increased odds of childhood overweight/obesity, while Asian ethnicity and above-mean household income (&gt;$64,999) showed a protective effect. There was no statistically significant relationship between dietary intake patterns and BMI status. Only 39% of overweight youth age 8-15 identified their weight status correctly. Weight-loss attempts were common among youth, 62% had tried to lose weight in the past year.   Conclusion: Significant associations between children’s BMI status and the socio-economic determinants age, ethnicity, household size and income highlight the importance of tailored prevention efforts. Incorrect self-perception of weight and weight control behaviours were common among children and adolescents.

Workers involved in hydraulic fracking processes are exposed to various types of chemicals and dusts in their workplaces, such as proppants, which hold open the fissures created in the fracking process. Recently, ceramic proppants have been developed that may be less hazardous to workers than traditional proppants. Pulmonary function testing of workers producing ceramic proppant was used to assess the potential inhalation hazards of ceramic proppant. Male workers (n = 100) from a producer of ceramic proppant were evaluated with pulmonary function test data collected and evaluated using The American Thoracic Society (ATS) acceptability criteria. A comparison group was selected from the Third National Health and Nutrition Examination Survey (NHANES III) spirometry laboratory subset. No pulmonary function deficits were found in the worker group in comparison to the NHANES III population. Multiple linear regression analysis showed that the mean FEV1 and FVC values in workers were 0.11 and 0.08 liters respectively, and were greater as compared to the NHANES III population. Curiously, an FEV1/FVC ratio of less than 0.8, when compared to the NHANES III group, produced an odds ratio of 0.44 in worker group, indicating less risk of preclinical pulmonary dysfunction. Overall, exposure to ceramic proppant was not found to produce an adverse impact on pulmonary function in workers engaged in the manufacture of ceramic proppant.