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Objective: Specific bioelectrical impedance vector analysis (spBIVA) is a recently proposed technique for the analysis of body composition. The aim of this study was to apply spBIVA to a sample of Italian and Spanish young adults and to define the new bioelectrical references for this Western Mediterranean population., Methods: A sample of 440 individuals (220 from Italy, 220 from Spain; 213 men, 227 women) aged 18-30 years was considered. Anthropometric (height, weight, relaxed upper arm, waist, and calf girths) and bioelectrical (resistance, reactance; 50 kHz, 800 μA) measurements were taken. In order to verify the need for new references, specific bioelectrical values were compared to the reference values for U.S. adults and Italian elderly by tolerance ellipses and Student's t test., Results: The mean specific bioelectrical values (resistivity, Rsp, and reactivity, Xcsp, Ohm·cm) were: Rsp (332.7 ± 41.7 Ω·cm), Xcsp (44.4 ± 6.8 Ω·cm), Zsp (335.6 ± 41.9 Ω·cm) and phase (7.6 ± 0.8°) in men; Rsp (388.6 ± 60 Ω·cm), Xcsp (43.7 ± 7.5 Ω·cm), Zsp (391.0 ± 60.3 Ω·cm) and phase (6.4 ± 0.7°) in women. Italo-Spanish bioelectrical vectors were mainly distributed (>90%) in the lower part of the tolerance ellipses for U.S. young adults, due to a shorter impedance (P < 0.001), indicative of a lower percent fat mass. Compared to Italian elders, they were mainly located in the left side (>90%), due to a higher phase (P < 0.001), indicative of higher body cell mass., Conclusions: These population and age-related differences indicate the need for new specific tolerance ellipses that can be used as references for assessing body composition in young adults from Western Mediterranean populations., (© 2015 Wiley Periodicals, Inc.)

The aim of this paper is to verify the existence of dispersion (or variability) dimorphism in several anthropometric traits, i.e., some skeletal, muscular, and adipose dimensions, and to provide an evaluation of this scarcely considered aspect of sex differences. This research focuses on two human samples from two different European regions, Sardinia (Italy) and the Basque Country (Spain). Twenty-three anthropometric measurements were taken. A first qualitative analysis was carried out comparing the profiles of the coefficients of variation of each variable in both sexes. Secondly, the equality of variability was verified with different tests. In the normal case, Student's t-test, as proposed by Sokal and Braumann ([1980] Syst. Zool. 29:50-63), was applied. In the more general case, it was necessary to resort to resampling techniques. A suitable bootstrap test was constructed and the results were compared, when possible, with those obtained by other methods. The measurements showed parallel trends in the two populations. In particular, subcutaneous skinfolds showed significant dispersion dimorphism, with the greatest coefficients of variation in men. We suggest that this result was linked to stronger canalization in female dimensions related to the reproductive function and influenced by sociocultural factors. We also suggest defining dispersion dimorphism, whose existence is confirmed by the results presented in this paper, as a descriptive pattern of phenotype variability in both sexes that can be specific of a given class of anthropometric traits., ((c) 2004 Wiley-Liss, Inc)