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Obesity associated with reduced lean mass and bone mass: an emerging and complex relationship involving biochemical, metabolic and functional changes

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Author(s):
Natasha Aparecida Grande de França
Total Authors: 1
Document type: Doctoral Thesis
Press: São Paulo.
Institution: Universidade de São Paulo (USP). Faculdade de Saúde Pública (FSP/CIR)
Defense date:
Examining board members:
Ligia Araujo Martini; Maysa Seabra Cendoroglo; Patrícia Chagas; Alex Antonio Florindo
Advisor: Ligia Araujo Martini
Abstract

Introduction - Aging is related to changes in body composition that can be driven or worsen according to the lifestyle. Given the impact of obesity, osteopenia (low bone density), and reduced lean mass, it is suggested that their concomitant presence would even increase the risk for morbimortality. Objective - To investigate the prevalence of the concomitant obesity, low lean mass and osteopenia in a sample of adults aged from 50 years and evaluate if simultaneous disturbances on body composition are associated with lower 25-hidroxyvitamin D [25(OH)D], worse lipid and glycemic profile, lower total energy expenditure and physical activity level, and poorer cardiorespiratory fitness. Methods: This is a cross-sectional study with 218 individuals (52% female), aged 63 (59 - 69) years recruited from the ISA-Capital 2015 and ISA Nutrição 2015. Appendicular lean mass (ALM), fat mass and bone mineral density (BMD) were measured by DXA. Obesity was defined as fat mass (kg) divided by height squared >9 kg/m2 and >13kg/m2 for men and women, respectively. Low lean mass (LM) was defined as ALM/BMI <0.789 and <0.512 for men and women, respectively. Osteopenia was defined as T-score at lumbar spine and/or femoral neck lower < -1.0. Subjects were then clustered into subgroups according to the presence/absence of body composition disturbances. Outcomes included grip strength, 25(OH)D concentrations, lipid and glycemic profiles, and lifestyle (physical activity and food intake). From the 218 participants we extracted a subsample of 43 (55% male), aged 65 (62-71) years to assess their cardiorespiratory fitness on a treadmill, resting energy expenditure (REE) by indirect calorimetry, and total energy expenditure (TEE) by doubly labeled water. Results - From the 218 individuals, 50 (23%) showed obesity associated with low LM and/or osteopenia, with 14 (6%) showing the concomitant 3 disturbances of body composition. A condition of obesity plus low LM and/or osteopenia was associated with reduced serum VD (-3 ng/ml), lower insulin sensitivity, higher visceral adiposity, lower grip strength, longer time spent in sedentary activities, and reduced protein intake by body weight. The subsample analysis (N = 43) showed worse cardiorespiratory fitness (VO2peak 5 ml/kg/min lower), higher REE (+300 kcal/day) and TEE (+140 kcal/day) than those without body composition disturbances, with no difference in total amount of energy expended in physical activities. Age, sex, and VD concentrations did not change the results. Conclusions - The prevalence of concomitant obesity and low LM and/or osteopenia was 23%. Such condition was associated with risk factors to the maintenance of these body composition disturbances, physical disabilities, cardiovascular diseases, and mortality. Considering these results in a context of population aging and lifestyle changes indicate the need to define strategies to better screening those at higher risk and avoiding that an isolated body composition disturbance state become a concurrent state. (AU)

FAPESP's process: 14/26787-0 - Physiological and genetic aspects interrelated to vitamin D in the osteosarcopenic obesity: health survey of the City of São Paulo - ISA capital
Grantee:Natasha Aparecida Grande de França
Support type: Scholarships in Brazil - Doctorate