Does the bone mineral content of oligomenorrheic women have an effect on body composition estimations?
The purpose of this study was to determine if the bone mineral content (BMC) of oligomenorrheic women is altered to an extent that differences would be obtained in the body composition estimations between 2- and 3-component models. The two-component models used to answer this research question were: (a) 7-site skinfolds (SKF) to determine body density (Db) and Siri's equation to determine body composition; and (b) hydrostatic weighing to determine Db and Siri's equation to determine body composition. The three-component models included: (a) hydrostatic weighing to determine Db, BMC as measured by the dual energy x-ray absorptiometry (DEXA), and Lohman's 3-component mineral density equation to determine body composition; and (b) the DEXA Lunar DPX IQ 5006 scan. Two-hundred and eighty-nine participants completed the Women's Health Questionnaire for screening prior to inclusion in the study. Study participants included 10 oligomenorrheic females (age = 20.70 ± 2.67 yr. height = 162.05 ± 5.38 cm, weight = 57.36 ± 9.36 kg). Descriptive statistics and a repeated one-way analysis of variance (ANOVA) were conducted to test for significant differences between four different methods of body composition assessment. There was a significant difference among the models (F (3, 27) = 26.89, p < .05). Follow-up paired t-tests between Lohman's 3-component mineral density model and Siri's 2-component model revealed a significant difference in body composition results, t(9) = 8.647. p < .05. This would lead one to conclude that the mineral density of this population has an effect on body composition estimations. However, there was also a significant difference between the 2-component models and between the 3-component models. Based on the results of this study, it seems that the method and equation chosen has the greatest impact on body composition estimations rather than the number of components included in the model.