title: Lean mass in obese adult subjects correlates with higher levels of vitamin D, insulin sensitivity and lower inflammation.
abstract: OBJECTIVE
  Several chronic metabolic alterations are present in obese subjects. While it is well known about the detrimental effect of abdominal adipose tissue on chronic metabolic clinical condition, less is known on the role of lean mass in obese subjects. Thus, the aim of our study was to evaluate the potential correlation of muscle mass, metabolic condition and inflammation status in obese individuals.
  
  
  METHODS
  The study included 426 obese subjects (86 men and 340 female; mean age 44.8 ± 14 years; BMI: 34.9 ± 6.1 kg/m(2)). Exclusion criteria were chronic medical conditions or use of medications affecting bone metabolism, alterations of hormonal and nutritional status, vitamin D supplementation, recent weight loss and prior bariatric surgery. Patients underwent measurements of bone mineral density (lumbar and hip) and body composition (lean mass, total and trunk fat mass) by dual X-ray absorptiometry and were evaluated for hormonal and metabolic profile and inflammatory markers.
  
  
  RESULTS
  Higher lean body mass (LM%) was inversely correlated with homeostasis model assessment of insulin resistance (p < 0.0091; r(2) 0.03938) and associated with lower fibrinogen levels (p < 0.0001; r(2) 0.1263). Interestingly, in obese subjects, LM% was associated with higher levels of vitamin D (p < 0.0001, r(2) 0.1140), osteocalcin (p < 0.0001, r(2) 0.2401) and insulin-like growth factor-1 (IGF-1) (p < 0.0002, r(2) 0.1367).
  
  
  CONCLUSIONS
  Our results show for the first time that in obese patients, higher amounts of lean mass are directly linked to a lower inflammatory profile and to better insulin sensitivity, but also to the presence of higher level of vitamin D and IGF-1. Moreover, these data suggest that higher levels of lean mass in obese people correlate with a better metabolic profile and, thus, strongly suggest the need to develop programs to facilitate an increase in physical activity in obese people.
authors.affiliation: Department Experimental Medicine, Section Medical Pathophysiology, Endocrinology and Nutrition, University "Sapienza" of Rome, Rome, Italy.
authors.forename: R
authors.initials: R
authors.lastname: Fornari
authors.affiliation: Department Experimental Medicine, Section Medical Pathophysiology, Endocrinology and Nutrition, University "Sapienza" of Rome, Rome, Italy.
authors.forename: D
authors.initials: D
authors.lastname: Francomano
authors.affiliation: Department Experimental Medicine, Section Medical Pathophysiology, Endocrinology and Nutrition, University "Sapienza" of Rome, Rome, Italy.|LiSa Laboratory, Azienda Ospedaliera-Universitaria "Policlinico Vittorio Emanuele", University of Catania, Catania, Italy.
authors.forename: E A
authors.initials: EA
authors.lastname: Greco
authors.affiliation: Department Experimental Medicine, Section Medical Pathophysiology, Endocrinology and Nutrition, University "Sapienza" of Rome, Rome, Italy.
authors.forename: C
authors.initials: C
authors.lastname: Marocco
authors.affiliation: Department Experimental Medicine, Section Medical Pathophysiology, Endocrinology and Nutrition, University "Sapienza" of Rome, Rome, Italy.
authors.forename: C
authors.initials: C
authors.lastname: Lubrano
authors.affiliation: LiSa Laboratory, Azienda Ospedaliera-Universitaria "Policlinico Vittorio Emanuele", University of Catania, Catania, Italy.|Department of Movement, Human and Health Sciences, Section of Health Sciences, University "Foro Italico" of Rome, Largo Lauro De Bosis 15, 00195, Rome, Italy.
authors.forename: F
authors.initials: F
authors.lastname: Wannenes
authors.affiliation: Department of Movement, Human and Health Sciences, Section of Health Sciences, University "Foro Italico" of Rome, Largo Lauro De Bosis 15, 00195, Rome, Italy.
authors.forename: V
authors.initials: V
authors.lastname: Papa
authors.affiliation: LiSa Laboratory, Azienda Ospedaliera-Universitaria "Policlinico Vittorio Emanuele", University of Catania, Catania, Italy.|Department of Movement, Human and Health Sciences, Section of Health Sciences, University "Foro Italico" of Rome, Largo Lauro De Bosis 15, 00195, Rome, Italy.
authors.forename: V M
authors.initials: VM
authors.lastname: Bimonte
authors.affiliation: Department Experimental Medicine, Section Medical Pathophysiology, Endocrinology and Nutrition, University "Sapienza" of Rome, Rome, Italy.
authors.forename: L M
authors.initials: LM
authors.lastname: Donini
authors.affiliation: Department Experimental Medicine, Section Medical Pathophysiology, Endocrinology and Nutrition, University "Sapienza" of Rome, Rome, Italy.
authors.forename: A
authors.initials: A
authors.lastname: Lenzi
authors.affiliation: Department Experimental Medicine, Section Medical Pathophysiology, Endocrinology and Nutrition, University "Sapienza" of Rome, Rome, Italy.|LiSa Laboratory, Azienda Ospedaliera-Universitaria "Policlinico Vittorio Emanuele", University of Catania, Catania, Italy.
authors.forename: A
authors.initials: A
authors.lastname: Aversa
authors.affiliation: Department of Movement, Human and Health Sciences, Section of Health Sciences, University "Foro Italico" of Rome, Largo Lauro De Bosis 15, 00195, Rome, Italy. silvia.migliaccio@uniroma4.it.
authors.forename: S
authors.initials: S
authors.lastname: Migliaccio
mesh_terms: D000328:Adult; D001823:Body Composition / Q000502:physiology*; D005260:Female; D006801:Humans; D007249:Inflammation / Q000097:blood / Q000378:metabolism*; D007333:Insulin Resistance / Q000502:physiology*; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000097:blood / Q000378:metabolism*; D014807:Vitamin D / Q000097:blood*
chemical_list: D014807:Vitamin D
keywords: Inflammation; Muscle; Obesity; Vitamin D