Changes in bone density and bone markers in rhythmic gymnasts and ballet dancers: implications for puberty and leptin levels

Abstract

Objective: Our aim was to compare physical activity and biochemical markers with bone mineral acquisition in rhythmic gymnasts and ballet dancers. Methods: Weight, height, body mass index, nutritional intake, bone age and menstrual histories were analyzed in nine rhythmic gymnasts, twelve ballet dancers and fourteen controls. Bone mineral density (BMD) was assessed by X-ray absorptiometry at the lumbar spine, hip and radius. Bone alkaline phosphatase (bAP) and amino-terminal propeptide of procollagen I (PNIP) in serum and urinary a-isomer of the carboxy-terminal telopeptide of collagen I (a-CTX) were measured. Results: Bone age was delayed 2 years and mean age at menarche was 15^0.9 years in rhythmic gymnasts and 13.7^1 years in ballet dancers, compared with 12.5^1 years in controls. Trocanteric and femoral neck BMD was significantly higher in rhythmic gymnasts compared with ballet dancers and controls. Right forearm (non-loaded zone) BMD was significantly decreased in rhythmic gymnasts and ballet dancers compared with controls. All subjects had normal bAP and PNIP levels, but the a-CTX/creatinine (Cr) ratio was increased in rhythmic gymnasts (P , 0.001) with an inverse correlation between right forearm BMD and the a-CTX/Cr ratio (r ¼ 2 0.74, P , 0.001). Serum leptin levels were decreased in rhythmic gymnasts and ballet dancers. Rhythmic gymnasts had a positive correlation between right forearm BMD and leptin levels (r ¼ 0.85, P , 0.001). Conclusions: Decreased bone mass in rhythmic gymnasts could be partially explained by an increase in bone resorption. Serum leptin levels could be implicated in the pubertal delay and be a good marker of bone mass in these subjects. European Journal of Endocrinology 151 491-496

Increased circulating adiponectin levels and decreased leptin/soluble leptin receptor ratio throughout puberty in female ballet dancers: association with body composition and the delay in puberty

“…BMD (g/cm 2 ), quantified as projected vertebral area of lumbar spine vertebrae (LSv) from L1 to L4, femoral neck (FN), femoral trochanter region, intertrochanter region, and Ward's triangle (WT) were measured at the different stages of puberty. Volumetric BMD of the lumbar spine (LSvBMD, g/cm 3 ) was calculated according to Carter's method (22). The results of fat mass are expressed in kilograms, and the percentage of regional fat mass was calculated to analyze the differences between central (trunk) and peripheral (extremity) distribution of fat tissue.…”

“…Growth during puberty depends on nutritional status, hormonal regulation, and genetic and environmental factors (2). Among environmental factors that can alter growth and sexual maturation are low body fat, stress, and intensive physical training (3). Their influence has been documented in different sports, but there is limited information on BDs, who have specific training and performance requirements.…”

Interação entre leptina, ginástica artística, puberdade e exercício em atletas do sexo feminino

“…Nas pesquisas em que a amostra foi composta por bailarinas e ginastas, foram observadas relações entre as baixas concentrações de leptina, os estados nutricionais debilitados e as medidas antropométricas abaixo da média (WeiMAnn et al, 1999;Muñoz et al, 2004). No caso na GA, esse fato pode estar relacionado à seleção natural na modalidade, que prioriza meninas com medidas antropométricas abaixo da média (roWlAnd, 2005), aos quadros de disfunções alimentares apresentadas por atletas dessa modalidade, assim como a exposição às altas cargas de treinamento desde a infância (BAPtiStA et al, 1997).…”

“…No caso na GA, esse fato pode estar relacionado à seleção natural na modalidade, que prioriza meninas com medidas antropométricas abaixo da média (roWlAnd, 2005), aos quadros de disfunções alimentares apresentadas por atletas dessa modalidade, assim como a exposição às altas cargas de treinamento desde a infância (BAPtiStA et al, 1997). mediante a observação dos resultados das pesquisas apresentadas, é possível afirmar que o balanço energético negativo (exercício associado a um estado nutricional debilitado) tem relação com as baixas concentrações de leptina plasmática e a desregulação do sistema reprodutório (lAughlin;yen, 1997;WeiMAnn et al, 1999;thong et al, 2000;Muñoz et al, 2004;KASSA-vuBu et al, 2006, MeirA et al, 2009.…”

“…O objetivo desta revisão é discutir resultados de pesquisas recentes que demonstram a influência da leptina no processo pubertário de atletas de GA do sexo feminino, e as desregulações no sistema reprodutório que essas atletas possuem, apresentando-se uma visão contextualizada do tema, pois estudos nesse campo ainda são bastante recentes (WeiMAnn et al, 1999;Muñoz et al, 2004;roWlAnd, 2005;Fenichel;WArren, 2007).…”