Preserved Bone Health in Adolescent Elite Rhythmic Gymnasts despite Hypoleptinemia

Abstract

Background/ Aims: Leptin is linked to hormonal disturbances occurring in anorexia and positively linked with bone mineral density. The aim of this study was to determine whether hypoleptinemia occurring in rhythmic gymnasts may affect bone health. Method: Leptin, insulin, cortisol, IGF1 levels and bone markers were determined in 36 rhythmic gymnasts (EG) and 20 controls (C). Body composition, BMD at the whole body (WBBMD), lumbar spine (LSBMD) and bone ultrasound properties (SOS, BUA) were measured. Results: The rhythmic gymnasts had lower fat mass and leptin level than the controls. There was no difference for IGF1, cortisol and insulin levels. Bone turnover rate was higher in elite gymnasts. The uncoupling index showed that remodeling favored the bone formation. LSBMD, WBBMD, SOS and BUA were higher in elite gymnasts after adjustment for fat mass. Leptin correlated positively with fat mass and negatively with physical activity. Conclusion: High impact training is able to counterbalance bone effects usually encountered in hormonally disturbed subjects. Our results suggest that hypoleptinaemia might be related to direct osteogenic effects and indirect hormonal mechanisms including preservation of IGF and cortisol levels.

Bone mineral density acquisition in peripubertal female rhythmic gymnasts is directly associated with plasma IGF1/IGF-binding protein 3 ratio

“…In this study, we confirmed the delayed age of menarche (mean age: 14 vs 12.6 years in the French population) (27) and the high prevalence of menstrual disorders. Conversely, no alteration in either peak bone mass acquisition or the IGF1/IGFBP3 ratio was observed, in agreement with previous reports (12,22). The multivariate analysis suggested that the plasma E 2 level may not be a strong determinant of BMD acquisition, except at the lumbar spine, a trabecular bone site that is more sensitive to estrogen deficiency (28).…”

“…Although a concomitant increase in BMD and leptin concentration has generally been observed during growth (8), the implication of leptin in bone mass accretion remains questionable in both young athletes (6,22,33) and controls (8,10). In our earlier cross-sectional study, we reported that the basal leptin level was not an independent predictor of BMD (7).…”

“…The high levels observed by this group may accentuate the effect of IGF1 on bone tissue. However, normal (22) and low IGF1 values have also been reported in gymnasts, and these discrepant findings may be due to the differences in the timing of investigation (23) or in nutritional status. The effect of IGF1 or IGFBP3 on bone mass acquisition was very recently supported by the results of Gruodyte et al (24), who also reported that the femoral neck and lumbar spine BMD were correlated with the IGF1/IGFBP3 molar ratio in rhythmic gymnasts, after adjusting for age, body height, and body mass.…”

“…Low leptin levels have been reported in athletes in relation to reduced body FM (22) and as a direct result of chronic exercise (22). Although a concomitant increase in BMD and leptin concentration has generally been observed during growth (8), the implication of leptin in bone mass accretion remains questionable in both young athletes (6,22,33) and controls (8,10).…”

Leptin and Insulin Resistance in Young Adult Obese Females: Effect of Eight Weeks Resistance Training

“…This idea of leptin as an insulin-sensitizing hormone and leptin deficiency, or resistance, as a potential link between obesity and diabetes has been reviewed recently (Yildiz, 2006). The plasma leptin level has a direct relation with the fat tissue and a negative relation with the body fitness or physical activity (Courteix et al, 2007). Physiological stress resulting from physical activity is one of the potential regulators of leptin secretion from adipose tissue.…”