Thesis
Bone regulating hormones and nutrients in the characterization of the metabolically healthy obese phenotype: a cross-sectional pilot study
Master of Science (M.S.), Drexel University
Jun 2016
DOI:
https://doi.org/10.17918/etd-6792
Abstract
The term metabolically healthy obese (MHO) phenotype has been used to describe those who present with a benign metabolic profile despite excess adiposity. The MHO phenotype is commonly defined as completely free of metabolic abnormalities or less than three components of metabolic syndrome. Bone regulating hormones, such as parathyroid hormone (PTH), 25-hydroxyvitamin D (25OHD), estrogen, and more recently osteocalcin, have been shown to play an important role in overall energy metabolism. Bone regulating nutrients such as calcium, vitamin D and magnesium (Mg) are also important regulators of energy metabolism. The goal of this study is to determine whether bone regulating hormones and nutrients can help characterize the MHO phenotype. We hypothesized that adequate Mg status, higher serum 25OHD and lower serum PTH concentrations would protect against metabolic abnormalities in overweight and obese individuals. The present case control design included 27 adult participants who were considered overweight or obese, evidenced by a body mass index (BMI) of 25-40 kg/m2. Measurements were obtained of the participants' Mg status and serum 25OHD, serum PTH levels, body fat percentage, trunk fat percentage, body fat mass, blood pressure, glycemic indices, lipid profile, and pro-inflammatory cytokines in order to determine what metabolic factors that set the metabolically healthy apart from the rest of the overweight and obese populations. Age and weight matched participants were then classified as MHO (n=13) or metabolically unhealthy obese (MUO) (n=14) using percent trunk fat based on the sample median (<19.2% for MHO and [greater than or equal to]19.2% for MUO). The collected data was analyzed using descriptive statistical methods appropriate for cross-study comparisons. The mean age of the MHO (29.99 ± 8.57 yr) and MUO (34.26 ± 9.38 yr) did not differ significantly. In the MHO group, serum insulin concentrations were significantly lower (p < 0.04) than the MUO group. Systolic BP did not differ between groups yet diastolic BP tended (p < 0.07) to be lower in the MHO group. Triglyceride and c-reactive protein (CRP) levels did not differ between groups. Magnesium intake tended to be higher in the MHO group (270.39 ± 181.71 mg/day) than the MUO group (195.38 ± 88.94 mg/day). Serum 25OHD concentrations did not differ between groups, however there was a significant difference (p < 0.04) in ionized Mg concentrations in the MHO group (0.565 ± 0.41 mmol/L) than in the MUO group (0.525 ± 0.050 mmol/L). Furthermore, serum PTH levels were significantly higher (p < 0.02) in the MUO group (61.77 ± 25.92 pg/mL) than the MHO group (40.19 ± 11.49 pg/mL). Serum osteocalcin concentrations and serum c-telopeptide collagen (CTx) concentrations tended to be higher in the MHO compared to the MUO group. These findings suggest that the bone regulating hormones can characterize the metabolically healthy obese phenotype. Future studies should consider examining these bone regulating hormones and nutrients in characterizing the MHO phenotype. Importantly, alterations in these hormones and nutrients can be a potential target for intervention for prevention of metabolic abnormalities.
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Details
- Title
- Bone regulating hormones and nutrients in the characterization of the metabolically healthy obese phenotype
- Creators
- Kendra Vos Becker - DU
- Contributors
- Deeptha Sukumar (Advisor) - Drexel University (1970-)
- Awarding Institution
- Drexel University
- Degree Awarded
- Master of Science (M.S.)
- Publisher
- Drexel University; Philadelphia, Pennsylvania
- Resource Type
- Thesis
- Language
- English
- Academic Unit
- Nutrition Sciences; College of Nursing and Health Professions; Drexel University
- Other Identifier
- 6792; 991014632725304721