Fat-free mass and fat mass reference values by dual-energy X-ray absorptiometry (DEXA) in a 20-80 year-old Italian population

BACKGROUND & AIMS: To establish reference values for fat-free mass (FFM), the FFM index (FFMI), fat mass (FM) and the FM index (FMI) in an Italian adult population, developing percentile distribution curves for age brackets between 20 and 80 years. METHODS: A multicenter, retrospective study was conducted on a sample of 1866 healthy Italian adults, 1435 females and 431 males. FFM and FM were measured by dual-energy X-ray absorptiometry. FFMI and FMI were calculated as the ratio of FFM and FM to height squared. RESULTS: The reference range for the FFMI (25-75th percentile) was similar in all age groups, i.e. 18.7-21 kg/m(2) in men and 14.9-17.2 kg/m(2) in women. In both genders, FM, the FMI and FM as a percentage of body weight (FM%) increased with age. The reference values for FM% in the two age brackets 20-29 and 60-69 were, respectively, 13-20% and 22.5-29.3% for men and 26.1-34.9%, 32.5-39.6% for women. CONCLUSIONS: These body composition ranges can be used by clinicians and nutritionists as reference values for a Caucasian population in the Mediterranean area when evaluating body composition variations occurring in aging, malnutrition and chronic diseases.