Relationship between bone mineral density, leptin and insulin concentration in Brazilian obese adolescents.
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.
do Prado
Wagner Luiz
WL
Physical Education High School, Pernambuco University, Pernambuco, Brazil.
de Piano
Aline
A
Lazaretti-Castro
Marise
M
de Mello
Marco Túlio
MT
Stella
Sérgio Garcia
SG
Tufik
Sergio
S
do Nascimento
Cláudia Maria Oller
CM
Oyama
Lila Missae
LM
Lofrano
Mara Cristina
MC
Tock
Lian
L
Caranti
Danielle Arisa
DA
Dâmaso
Ana Raimunda
AR
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
D015415:Biomarkers; D007328:Insulin; D020738:Leptin