Many women with mild to moderate mental retardation (MMR) exhibit low levels of physical activity, muscle strength, and muscle mass, which place these individuals at risk for osteoporosis. Bone mineral density (BMD), the primary index of osteoporosis, of the femoral neck and the whole body was measured in premenopausal women with (M age = 28.14 ± 8.43) and without (M age = 29.64 ± 10.86) mental retardation (MMR and NMR, respectively). Multivariate analyses revealed no differences (p > .05) between groups (MMR = 16, NMR = 16) for BMD values. Significant differences existed (p < .05) between groups on body composition and muscle strength variables. In the MMR group, significant positive relationships (p < .05) were found between lean muscle mass and both femoral neck (r = .74) and whole body (r = .81) BMD. Unaccounted lifestyle factors may have contributed to nonsignificant BMD values between groups.
Manny Felix is with the Department of Exercise and Sport Science at the University of Wisconsin–La Crosse, 115 Wittich Hall, La Crosse, WI 54601. Jeff McCubbin is with the College of Health and Human Performance at Oregon State University, Women’s Building 123, Corvallis, OR 97331. Janet Shaw is with the Department of Exercise and Sport Science at the University of Utah, 300 S. 1850 E., Room 259, Salt Lake City, UT 84112-0920.