Healthy overweight/obese youth: early osteosarcopenic obesity features Charikleia Stefanaki * , Melpomeni Peppa † , Dario Boschiero ‡ and George P. Chrousos *,§ * 1 st Department of Pediatrics and Choremeion Research Laboratory, † Endocrine and Metabolic Bone Disorders Unit, 2 nd Department of Internal Propaedeutic Medicine, Research Institute and Diabetes Center, Attikon University Hospital, Athens Medical School, National and Kapodistrian University of Athens, Athens, Greece, ‡ BIOTEKNA Co., Venice, Italy, § Biomedical Research Foundation, Academy of Athens, Athens, Greece ABSTRACT Background Osteosarcopenic obesity was recently described as a variant phenotype of obesity, mainly observed in old age. This nested case–control study was performed to detect the differences in body compo- sition between young, healthy overweight/obese and healthy lean populations of both genders. Our null hypothesis was that except for the fat mass, there would be absence of body composition differences, namely skeletal muscle and bone masses, between the groups. Methods We used an advanced bio-impedance device to determine the body composition and measured cir- culating CRP (hsCRP) and diurnal salivary cortisol concentrations, as indices of inflammation and chronic stress, respectively. Overall, 2551 subjects aged 18–21 years participated in the study. Results The healthy lean group included 1072 participants [900 males (84%) and 172 females (16%)], and the healthy overweight/obese group included 1479 participants [74 males (5%) and 1405 females (95%)]. Healthy overweight/obese participants presented with an increased fat mass (P < 0Á001), as expected, but lower muscle (P < 0Á001) and bone (P < 0Á001) masses than lean controls. These findings were accompanied by increased extracellular water compartments, circulating hsCRP levels and evening salivary cortisol concentra- tions in the healthy overweight/obese group. Conclusions Our study suggests that ‘osteosarcopenic’ elements exist even in very young populations. These may represent a ‘precursor’ or forme fruste of the osteosarcopenic obesity phenotype in young healthy over- weight/obese subjects, who may progressively develop osteosarcopenia in its full form at an older age. Our study highlights the significance of body composition analysis in medical practice, improving prevention and alleviating later health-related economic burden. Keywords bio-impedance, body composition, fat mass, muscle mass, osteopenia, osteosarcopenic obesity, sarcopenia, young adults. Eur J Clin Invest 2016; 46 (9): 767–778 Introduction The majority of body composition studies have indicated that the human skeletal muscle mass is a robust index of health status, life quality and life expectancy [1–5]. A new clinical entity has recently emerged in the field of meta- bolism in the elderly termed ‘osteosarcopenic obesity’ [6]. This is an odd combination of obesity, sarcopenia and osteopenia or osteoporosis [7]. No clear definition of osteosarcopenic obesity has been proposed in the young; as yet, however, one might employ standard statistical cut-off points at the 95% confidence intervals or two standard deviations of the healthy lean population to define osteosarcopenic subjects. Several cut-off points have been employed for different body composition evaluation methods, such as bio-impedance, skinfold thickness mea- surements, DXA and computerized axial or MRI tomogra- phy (CT) [8]. Clinical consequences of osteosarcopenic obesity in the elderly include an increased risk of bone fractures, insulin resistance, impaired functional status, physical disability, frailty, increased morbidity and mor- tality and high susceptibility to infections [9]. Ageing, chronic inflammation and sustained psychosocial stress are risk factors for the development and progression of osteosarcopenic obesity [10]. Indeed, smouldering, low-grade systemic inflammation and chronic – real or perceived – stress European Journal of Clinical Investigation Vol 46 767 DOI: 10.1111/eci.12659 ORIGINAL ARTICLE