Prevalence of obesity and its concomitant complications as Type 2 Diabetes and cardiovascular diseases are increasing world-wide. Magnetic resonance imaging has been established as a gold-standard for quantification of different adipose tissue (AT) compartments over the last several years with visceral adipose tissue (VAT) playing a special role in the pathogenesis of insulin resistance. Up to now the amount of fat is given in absolute values (liters). However, this measure does not allow a detailed characterization of the subjects as it does not directly reflect AT distribution, and quantity has to be interpreted differently for subjects with different size. Therefore, new indices are introduced for a more reliable definition for whole-body quantity and distribution of AT and to show up age- and gender-related differences.A cohort of 952 subjects (m/f 349/603, age 45.1±13.0 years, BMI 30.2±5.7 kg/m²) underwent an initial MR examination in the framework of longitudinal intervention studies. MRI was performed on a 1.5 T whole body scanner (Magnetom Sonata, Siemens Healthcare, Germany) in the early morning after overnight fasting applying an axial T1-weighted fast spin-echo technique (TE/TR 12ms/460ms) with a slice thickness of 10mm and an interslice gap of 10mm as described in [1]. Segmentation was performed by a home-built automatic procedure based on Matlab [2]. Following AT compartments were determined: AT of lower (AT_LE) and upper extremities (AT_UE), VAT and non-visceral AT of the trunk (NVAT_T). For an assessment of AT distribution, the percentage of the respective compartments in relation to total AT was calculated, AT quantity was corrected for height by dividing the amount by squared height – comparable to BMI – resulting in respective fat mass indices. Anthropometric data were assessed immediately after the MR examination.Anthropometrics and fat indices are given in Table 1. Gender related differences in AT distribution and quantity are listed in Table 1. Besides the known fact that males are characterized by a higher amount of VAT – as expressed by more than doubled %VAT for AT distribution and 1.7-fold higher VAT-index for VAT quantity, significant differences for all AT compartments are revealed. AT distribution changes with increasing age with %VAT being clearly more pronounced for both, males (r = 0.65) and females (r = 0.54), going along with a decrease in %AT_LE (males: r = -0.48, females: r = -0.33) whereas NVAT_T and AT_UE are almost unchanged. Figure 1 shows the age-dependent increase of %VAT, indicating a slightly steeper slope for post-menopausal women (aged > 50 years) whereas this redistribution is different for males with a flatter slope for the same age group. AT indices are depicted in Figure 2 for different age groups highlighting an increasing amount of VAT with concomitant decrease in AT_LE for females but not for males.MR-based phenotyping is of increasing interest in cross-sectional studies on large cohorts [3,4]. In this connection, quantification of different adipose tissue compartments comes to the fore in order to characterize people at risk for metabolic and cardiovascular diseases. The introduced indices for identification of quantity and distribution of adipose tissue in combination with the age- and gender related differences might lead to a better understanding of body composition and its influence on metabolic parameters. Whether or not these indices lead to additional information concerning changes during lifestyle intervention and help in identifying people which will probably be non-responders in terms of metabolic status [5] has to be determined in further analyses.In conclusion, MRI has become a gold-standard for non-invasive phenotyping of healthy subjects for different clinical problems and is nowadays being applied in studies on large cohorts world-wide. In order to shed new light in the pathogenesis of metabolic diseases and to evaluate the special role of different adipose tissue compartments, a more detailed classification – going beyond simple volumetrics – is proposed in this work that might help in future (epidemiological) cross-sectional and interventional analyses.