History of amenorrhoea compromises some of the exercise-induced benefits in cortical and trabecular bone in the peripheral and axial skeleton: a study in retired elite gymnasts

BACKGROUND

Female gymnasts frequently present with overt signs of hypoestrogenism, such as late menarche or menstrual dysfunction. The objective was to investigate the impact of history of amenorrhoea on the exercise-induced skeletal benefits in bone geometry and volumetric density in retired elite gymnasts.

SUBJECTS AND METHODS

24 retired artistic gymnasts, aged 17-36 years, who had been training for at least 15 h/week at the peak of their career and had been retired for 3-18 years were recruited. They had not been engaged in more than 2 h/week of regular physical activity since retirement. Former gymnasts who reported history of amenorrhoea ('AME', n=12: either primary or secondary amenorrhoea) were compared with former gymnasts ('NO-AME', n=12) and controls ('C', n=26) who did not report history of amenorrhoea. Bone mineral content (BMC), total bone area (ToA) and total volumetric density (ToD) were measured by pQCT at the radius and tibia (4% and 66%). Trabecular volumetric density (TrD) and bone strength index (BSI) were measured at the 4% sites. Cortical area (CoA), cortical thickness (CoTh), medullary area (MedA), cortical volumetric density (CoD), stress-strain index (SSI) and muscle and fat area were measured at the 66% sites. Spinal BMC, areal BMD and bone mineral apparent density (BMAD) were measured by DXA.

RESULTS

Menarcheal age was delayed in AME when compared to NO-AME (16.4+/-0.5 years vs. 13.3+/-0.4 years, p<0.001). No differences were detected between AME and C for height-adjusted spinal BMC, aBMD and BMAD, TrD and BSI at the distal radius and tibia, CoA at the proximal radius, whereas these parameters were greater in NO-AME than C (p<0.05-0.005). AME had lower TrD and BSI at the distal radius, and lower spinal BMAD than NO-AME (p<0.05) but they had greater ToA at the distal radius (p<0.05).

CONCLUSION

Greater spinal BMC, aBMD and BMAD as well as trabecular volumetric density and bone strength in the peripheral skeleton were found in former gymnasts without a history of menstrual dysfunction but not in those who reported either primary or secondary amenorrhoea. History of amenorrhoea may have compromised some of the skeletal benefits associated with high-impact gymnastics training.

High bone density in young Hutterite children

We previously reported greater than average aBMD in adult Hutterites; however, it is unknown whether higher aBMD occurs at younger ages. We examined Hutterite children to test the hypotheses that aBMD Z-scores in younger (<15 years) Hutterite children would be similar to reference data; but greater in older children after they enter the adult workforce at age 15. A secondary aim was to determine lifestyle factors associated with bone measures among Hutterite children. Hip, femoral neck, and spine BMC and aBMD were measured in 323 Hutterite children aged 8 through 19 years: 186 (108 girls) were <15 years (younger) and 137 (87 girls) were >or=15 years (older). Anthropometric measurements and activity and dietary recalls were obtained. Overall, children were lighter (Z=-0.29+/-0.72 [mean+/-SD]), shorter (Z=-0.15+/-0.86, and had lower BMI's (Z=-0.27+/-0.70) than other South Dakota children residing in the same counties (all, p<or=0.002). Older girls and boys had higher percent time in moderate+vigorous activity (21+/-10% and 29+/-11% [mean+/-SD]) than younger girls and boys (15+/-10% and 18+/-10%, both p<0.001). Younger girls and boys had high hip aBMD Z-scores (0.30+/-1.0, 0.44+/-0.97; both greater than 0 at p<or=0.002). Younger males had low spine Z-score (-0.27+/-1.15, p=0.04). None of the Z-scores for the older ages were different from 0. Controlling for covariates, miles walked/day and grip strength were associated with greater hip bone area among girls (both, p<0.05). Grip strength was associated with hip and femoral neck BMC and hip aBMD among boys (all, p<0.05). Femoral neck bone area was inversely associated with calcium intake among boys (p<or=0.05), while higher hip BMC and spine BMC and aBMD were associated with increased vitamin D intake (all, p<or=0.05). Lean mass was an independent predictor of all bone measures, while fat mass was inversely associated with most measures of bone area. In summary, contrary to our hypothesis younger Hutterite children had greater hip aBMD Z scores than the normative DXA database, whereas older children did not. We speculate that high activity levels during the rapid growth phase leads to increased bone turnover and bone size; following bone consolidation later in young adulthood this will result in greater bone size and aBMD.