Background: Although adequate hydration is recommended for healthy nutrition, the link between less water consumption and obesity is not exactly known. It was demonstrated that less hydrated adults had a higher body mass index (BMI). Data in children are rather limited. Our aim was to compare the hydration status between obese and non-obese children.
Subjects and methods: Children aged between 7 and 18 years who had a BMI over 2 standard deviation score (SDS) with exogenous obesity were included in the study group (Group 1, n=31), healthy volunteers with a normal weight were included in the control group (Group 2, n=30). The anthropometric measurements were performed and body composition analysis was applied using bioelectrical impedance analysis method (TANITA BC 418). Urine density was tested at the same time of the day after ad libitum water consumption and lunch. The fluid intake diary was recorded over two consecutive days using two different methods. Total fluid intake was compared with European Food Safety Authority (EFSA) recommendations. The intake of water and sugar sweetened beverages (SSBs) were compared between groups.
Results: There was no differences regarding age and gender between groups (P>0.005 for both). The median BMI-SDS was 2.57 (0.52) kg/m2 in Group 1 and 0.01 (1.48) kg/m2 in Group 2 (P<0.001). Subjects in Group 1 had a higher percentage of body fat (P<0.001), and lower percentages of total body water (TBW) and fat free mass (P=0.007 and<0.001 respectively). The fluid intake per body surface of Group 1 was found significantly less than Group 2 both in the first and in the second day (P<0.001). The urine density was found significantly higher in Group 1 (1020 (10) and 1015(10), P<0.001). Urine density correlated positively with BMI-SDS (r=0.508, P=<0.001), negatively with TBW (r=−0.412, P=0.001) and fluid intake per body surface (first day: r=−0.477, P<0.001, second day: r=−0.519, P<0.001). While 55% of subjects (n=17) in Group 1 satisfied the recommended daily fluid intake, this was 80% (n=24) in Group 2 (P=0.036). The consumption of SSBs was 71% in Group 1 and 20% in Group 2, with higher amount in Group 1 (median 200 ml vs 0 ml, P<0.001).
Conclusions: We found that obese children had less fluid intake, lower TBW percentages and higher urine density. The results of this cross-sectional preliminary study showed that obese children were less hydrated than normal weighted children.
27 - 29 Sep 2018
European Society for Paediatric Endocrinology