Date of Award
1-1-2025
Document Type
Dissertation
Degree Name
Ph.D. in Nutrition and Hospitality Management
First Advisor
Nadeeja Wijayatunga
Second Advisor
Melinda Valliant
Third Advisor
Georgianna Mann
School
University of Mississippi
Relational Format
dissertation/thesis
Abstract
Obesity is a complex chronic condition characterized by the excessive accumulation of body fat. While numerous studies have highlighted the risks of adverse complications associated with obesity, limited research has explored the relationship of body composition phenotypes, more specifically normal weight obesity with aging, and bone health. Also, the prevalence of unhealthy lean phenotypes in adults in the U.S. is not clear. A secondary-data analysis of the National Health and Nutrition Examination Survey (NHANES) 1999-2002 were performed to further examine the relationship between body composition phenotypes—normal weight lean (NWL), overweight/obesity with normal body fat percentage (OBL), normal weight obesity (NWO), and overweight/obesity with higher body fat percentage (BF%) (OBO) — and aging markers, including telomere length, biological age (BioAge), and phenotypic age (PhenoAge). Generalized linear regression models revealed that the OBO phenotype was inversely associated with telomere length (β = -0.029, 95% CI: -0.046 to -0.011, P = 0.002). Both OBL and OBO phenotypes were positively associated with increased BioAge and PhenoAge (β = 0.042 and 0.050, both P < 0.001), even after adjusting for demographic, lifestyle, and socioeconomic covariates. Conversely, the NWO phenotype did not show a significant association with telomere length BioAge or PhenoAge in adjusted models. According to the present cross-sectional study, OBO and OBL may cause a significant acceleration in aging process compared to individuals with NWL.
A cross-sectional study of the NHANES 2013-2014 and 2017-2018 cycles was conducted to determine the association between body composition phenotypes, including NWL, OBL, NWO, and OBO, and bone health parameters, namely total bone mineral density (BMD), bone mineral content (BMC), femoral neck BMD, and spinal BMD (L1-L4) in healthy adults. Generalized linear regression models revealed that the OBL phenotype was significantly associated with higher total BMD, total BMC, femoral BMD, and spinal BMD (P < 0.001) after adjusting for covariates. The OBO phenotype was positively associated with spinal BMD and femoral BMD (P < 0.001). On the other hand, no significant association was found between the NWO phenotype and bone health parameters after adjusting for covariates. A positive correlation was observed for body weight, BMI, waist circumference, and all bone parameters (P < 0.001), while BF% was inversely associated with total BMD and BMC (P < 0.001). Further longitudinal and clinical studies are needed to establish the causal association between body composition phenotypes and bone health parameters.
A cross-sectional study of four NHANES cycles (2011–2018) was performed to examine the prevalence of healthy and unhealthy lean phenotypes, including normal weight lean (NWL), normal weight obesity (NWO), normal weight central obesity (NWCO), and metabolically unhealthy normal weight (MUNW) in normal BMI adults. The prevalence of NWL phenotype was 51.58%, while 21.74% were classified as NWO only, 1.28% as NWCO only, and 11.06% as MUNW only. Overlapping phenotypes were also observed. In this regard, 2.70% is categorized as NWO + NWCO, 9.32% as NWO + MUNW, 0.60% as NWCO + MUNW, and 1.70% had characteristics of all three phenotypes. The prevalence of unhealthy lean phenotypes increased with age and varied significantly by gender and race/ethnicity. Of note, NWO was more prevalent among women, while MUNW was more common in men. The findings demonstrated a significant prevalence of unhealthy lean phenotypes in the U.S. population. However, further studies are needed to investigate the health implications of these unhealthy lean phenotypes and evaluate key characteristics of overlapping phenotypes.
Recommended Citation
Sefidmooye Azar, Pouria, "Exploring Aging and Bone Health in Normal Weight Obesity and The Prevalence of Unhealthy Lean Phenotypes" (2025). Electronic Theses and Dissertations. 3383.
https://egrove.olemiss.edu/etd/3383