BODY-SIZE, BIOLOGICAL MATURATION, AND SPORT PARTICIPATION RELATED TO CORTICAL BONE IN ADOLESCENT GIRLS

The purposes of this study were twofold: (1) to describe the growth of metacarpal bone dimensions in a large sample (n = 819) of Flemish gir ls, 12-18 years, and (2) to investigate the relationship among cortica l bone dimensions, biological maturation, and participation in sports activities. Besides body mass and stature, Tanner-Whitehouse skeletal age (SA) was estimated and menarcheal status was assessed. Second meta carpal bone dimensions were measured on radiographs. Sports participat ion was determined by a standardized questionnaire. Results show that whereas medullary diameter decreased, all other second metacarpal dime nsions increased significantly with age. When the girls were divided i nto five subgroups by SA, significant differences were found for metac arpal bone dimensions among the groups. Analysis of covariance reveale d that skeletal maturity significantly differentiated for medullary di ameter, cortical thickness, cortical area, and percent cortical area, even when chronological age, body mass, and stature were partialled ou t. However, no differences were found between contrasting SA groups fo r metacarpal length and periosteal diameter when chronological age, bo dy mass, and stature were held constant. The metacarpals of postmenarc heal girls are approximately 4% longer and approximately 7% wider, and had approximately 14% more bone area than age-matched, premenarcheal peers. No differences were found in periosteal diameter between pre- a nd postmenarcheal 14-15-year-old girls. Finally, sports participation was not associated with cortical bone in this group of healthy females (-0.16 less-than-or-equal-to r less-than-or-equal-to 0.17). (C) 1994 Wiley-Liss, Inc.