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Genetic Determinants Of Variation In The Gh/Igf-1 Axis And Their Relationship To Cardiometabolic Health, Rafael Luis Aguirre Guillen

Theses and Dissertations

Background: In a study of Mexican Americans, we performed analyses of GEI and pleiotropy in the axis in relation to MS. GH/IGF-1 axis components were studied. Model parameters and likelihoods were estimated by maximum likelihood.

Results: Pleiotropy was observed for IGFBP3 (p

Conclusions: IGF-I and IGFBP3 are genetically correlated with MS whereas MS influences the additive genetic variance in IGFBP1 variables mainly but also in IGF-I somewhat by virtue of the VH exhibited by IGF-I/IGFBP1.

Physical Activity Level And Insulin Resistance In 6,500 Nhanes Adults: The Role Of Abdominal Obesity, James R Fowler

Theses and Dissertations

OBJECTIVE: This cross-sectional study investigated insulin resistance (IR) variation across physical activity (PA) levels in U.S. adults. METHODS: MET-minutes were utilized to quantify PA using 2 methods: 4 categories were based on relative MET-minutes, and 5 were based on U.S. PA guidelines. IR was indexed using the homeostatic model assessment (HOMA). Effect modification was tested by dividing waist circumferences into sex-specific quartiles, and then evaluating the relationship between PA and HOMA-IR within each quartile separately. RESULTS: Relative PA was associated with HOMA-IR after controlling for demographic and demographic and lifestyle covariates (F = 11.5, P < 0.0001 and F = 6.0, P = 0.0012, respectively). Adjusting for demographic and demographic and lifestyle covariates also revealed relationships between guideline-based PA and HOMA-IR (F = 8.0, P < 0.0001 and F = 4.9, P = 0.0017, respectively). Controlling for waist circumference with the other covariates nullified the relationship between PA and HOMA-IR. Effect modification testing showed that when the sample was delimited to adults with extra-large waists (Quartile 4), relative (F = 5.6, P = 0.0019), and guideline-based PA (F = 3.7, P = 0.0098) and HOMA-IR were related. PA and HOMA-IR were not related within the other quartiles. CONCLUSION: High levels of PA may play a meaningful role in glucose and insulin metabolism in those with abdominal obesity, but not in adults with smaller waists.

Physical Activity Of Preschoolers With Developmental Disabilities And Delays, Michaela A. Schenkelberg

Theses and Dissertations

Children with developmental disabilities and delays are at greater risk for developing overweight and obesity compared to typically developing peers. Participation in regular physical activity is a modifiable behavior that is consistently associated with improved weight status and other positive health outcomes. Previous studies have identified numerous individual- and environmental-level factors that associate with physical activity among school-age children with and without disabilities. However, little is known about physical activity behaviors and related correlates among preschool-aged children with disabilities (ages 3 – 5 years), especially while they are in preschool settings. Therefore, the overall purpose of this dissertation was to …