Energy regulating hormones and the development of obesity and diabetes

• Main Author: Cahill, Farrell
• Format: Thesis
• Language: English
• Published: Memorial University of Newfoundland 2015
• Subjects: Newfoundland
• Online Access: https://research.library.mun.ca/8345/; https://research.library.mun.ca/8345/1/thesis.pdf

Obesity, a complex multifactorial disease, is a serious public health concern due to numerous obesity-related comorbidities thought to result from various hormones in combination with lifestyle and environmental factors. At present, the role of only a fraction of the hormones involved in obesity have been well defined. The aims of this thesis were to investigate: 1) the association of appetite regulating hormones with obesity and obesity-related phenotypes in the Newfoundland and Labrador general population; 2) the response and interaction of appetite and energy regulating hormones on obesity development under a positive energy challenge; 3) the association of dietary magnesium intake with obesity and diabetes; 4) testing the validity of the body adiposity index (BAI) in a Caucasian population; 5) the association of BAI with cardiometabolic risk factors (CRF); 6) and the development of a novel and more accurate equation than body mass index (BMI)and BAI to evaluate adiposity. All of these were achieved using data from two different studies - the large scale, population-based CODING (Complex Diseases in the Newfoundland Population: Environment and Genetics) study and an intervention-based, 7-day positive energy surplus study. We have discovered that circulating PYY (appetite suppressant) is not significantly associated with obesity status defined by either percent body fat () or BMI. However, circulating PYY was influenced by age, smoking, medication use, and menopausal status in women. We also sought to explore the endocrine response of normal-weight, overweight and obese individuals to a 7-day hypercaloric diet. We demonstrated that PYY increased in response to overfeeding, but was not associated with changes in insulin resistance and/or weight. We also found that adiponectin (insulin sensitizer) was not associated with obesity status but the significant increase in adiponectin, due to overfeeding, was significantly associated with insulin resistance. We also investigated the impact of dietary magnesium on ...