Urinary volatile organic compounds in overweight compared to normal-weight children: results from the Italian I. Family cohort

Accumulating evidence shows that urinary volatile organic compounds (VOCs) could be perturbed in many physiological and pathological states, including several diseases and different dietary exposures. Few studies investigated the urinary metabolic signature associated to excess body weight and obesity in adult populations, while a different VOCs profile was found in exhaled breath in obese as compared to lean children. Aim of this study was to evaluate the VOCs profile in the urine of 21 overweight/obese (OW/Ob) and 28 normal-weight (NW) children belonging to the Italian cohort of the I. Family study. Urine samples were analysed by Solid Phase Micro-Extraction (SPME) GC-MS under both acidic and alkaline conditions, in order to profile a wider range of urinary volatiles with different physicochemical properties. Multivariate statistics techniques were applied to bioanalytical data to visualize clusters of cases and detect the VOCs able to differentiate OW/Ob from NW children. Under alkaline conditions, fourteen VOCs were identified, distinguishing OW/Ob from NW children. Our results suggest that VOCs signatures differ between OW/Ob and NW children. However, the biological and pathophysiological meaning of the observed differences needs to be elucidated, in order to better understand the potential of urinary VOCs as early metabolic biomarkers of obesity.