ORIGINAL ARTICLES   

The Journal of Sports Medicine and Physical Fitness 1998 September;38(3):234-9

Copyright © 1999 EDIZIONI MINERVA MEDICA

language: English

Lumbar bone mineral density in adolescent female runners

Moen S. M. ¹, Sanborn C. F. ², Dimarco N. M. ², Gench B. ², Bonnick S. L. ³, Keizer H. A. ⁴, Menheere P. P. C. A. ⁵

¹ Dallas Baptist University, Dallas, USA; ² Texas Woman’s University; ³ Aerobics Center, Dallas, Texas; ⁴ University of Limburg, The Netherlands; ⁵ Academic Hospital, The Netherlands

Background. The pur­pose of ­this ­study was to deter­mine if ­there ­were sig­nif­i­cant dif­fer­enc­es in lum­bar ­bone min­er­al den­sity (L2-L4, g/ cm2) or sev­er­al hor­mones ­among 3 ­groups of ado­les­cent ­females: 10 amen­or­rhe­ic run­ners, 10 eumen­or­rhe­ic run­ners, and 10 eumen­or­rhe­ic con­trols.
Methods. Experimental ­design: com­par­a­tive.
Setting. Cooper Clinic, Aerobics Center, Dallas, Texas.
Patients or par­tic­i­pants. The sub­jects ­were ­white, non-smok­ers, ­aged 15.1-18.8 ­years, who ­were not tak­ing ­birth con­trol ­pills. All amen­or­rhe­ic run­ners had ­less ­than 5 men­stru­al peri­od in the ­past ­year, aver­ag­ing 2,4 peri­ods. The run­ners aver­aged approx­i­mate­ly 36 ­miles/­week (58.1 km) dur­ing the ­last 9 ­months of ­their train­ing sea­son and had ­been run­ning for 1-5 ­years.
Interventions. ­None.
Measures. lum­bar ­bone min­er­al den­sity (BMD), 10 hor­mones, per­cent­age of ­body fat, and die­tary ­intake ­were meas­ured.
Results. Mean lum­bar BMD (g/cm2) did not dif­fer sig­nif­i­cant­ly ­among ­groups (amen­or­rhe­ic run­ners=1.134, eumen­or­rhe­ic run­ners=1.165, con­trols=1.148). However, expect­ed ­trends ­were ­observed. Compared to the con­trols, the amen­or­rhe­ic run­ners tend­ed to ­have low­er lum­bar BMD and the eumen­or­rhe­ic run­ners, high­er. Although ­there ­were sig­nif­i­cant dif­fer­enc­es in con­cen­tra­tions of ­five ser­um hor­mones meas­ured, all ­mean hor­mo­nal val­ues ­were with­in nor­mal rang­es. Calcium ­intakes ­were low for all ­groups.
Conclusions. In ­this ­study, ­with its ­small num­ber of sub­jects and ­great var­i­abil­ity with­in ­each ­group, it was con­clud­ed ­that ­there is no sig­nif­i­cant dif­fer­ence ­among amen­or­rhe­ic run­ners, eumen­or­rhe­ic run­ners, and con­trols in lum­bar BMD. However, a long­er peri­od of ame­nor­rhea ­might ­result in sig­nif­i­cant­ly low­er BMD for the amen­or­rhe­ic run­ners.