title: Relationship between bone mineral density, leptin and insulin concentration in Brazilian obese adolescents.
abstract: Despite the epidemic of adolescent obesity, the effect of obesity and hormones on bone mineral accrual during growth is poorly understood. Studies using dual-energy X-ray to examine the effect of obesity on bone mass in children and adolescents have yielded conflicting results. The aim of this study was to explore the combined and independent contributions of body mass index, body composition, leptin, insulin, glucose levels and Homeostasis Model Assessment Insulin Resistance (HOMA-IR) to bone mineral density (BMD) and bone mineral content in a group of Brazilian obese adolescents. This study included 109 post-pubescent obese adolescents. A whole-body dual-energy X-ray absorptiometry scan was performed,using a HOLOGIC QDR4200, to determine whole-body BMD and body composition. Blood samples were collected in the outpatient clinic after an overnight fast, and evaluated for fasting blood glucose and immunoreactive insulin. Leptin levels were assessed with a radioimmunoassay kit. Insulin resistance was assessed by HOMA-IR and the quantitative insulin sensitivity check index. Our results showed that insulin levels and HOMA-IR correlated negatively with BMD and a linear regression analysis showed that serum leptin is inversely associated to BMD adjusted for body mass. In conclusion, our data support the hypothesis that leptin, insulin and HOMA-IR are inversely associated with BMD and play a significant direct role in bone metabolism.
authors.affiliation: Physical Education High School, Pernambuco University, Pernambuco, Brazil.
authors.forename: Wagner Luiz
authors.initials: WL
authors.lastname: do Prado
authors.forename: Aline
authors.initials: A
authors.lastname: de Piano
authors.forename: Marise
authors.initials: M
authors.lastname: Lazaretti-Castro
authors.forename: Marco Túlio
authors.initials: MT
authors.lastname: de Mello
authors.forename: Sérgio Garcia
authors.initials: SG
authors.lastname: Stella
authors.forename: Sergio
authors.initials: S
authors.lastname: Tufik
authors.forename: Cláudia Maria Oller
authors.initials: CM
authors.lastname: do Nascimento
authors.forename: Lila Missae
authors.initials: LM
authors.lastname: Oyama
authors.forename: Mara Cristina
authors.initials: MC
authors.lastname: Lofrano
authors.forename: Lian
authors.initials: L
authors.lastname: Tock
authors.forename: Danielle Arisa
authors.initials: DA
authors.lastname: Caranti
authors.forename: Ana Raimunda
authors.initials: AR
authors.lastname: Dâmaso
mesh_terms: D050154:Adiposity / Q000502:physiology; D000293:Adolescent; D044467:American Indian or Alaska Native; D000886:Anthropometry; D015415:Biomarkers / Q000097:blood; D001835:Body Weight / Q000502:physiology; D015519:Bone Density / Q000502:physiology*; D001938:Brazil; D005260:Female; D006801:Humans; D007328:Insulin / Q000097:blood*; D020738:Leptin / Q000097:blood*; D008297:Male; D009765:Obesity / Q000097:blood* / Q000503:physiopathology*; D012044:Regression Analysis
chemical_list: D015415:Biomarkers; D007328:Insulin; D020738:Leptin