Plasma dosage of ghrelin and leptin related to gastric emptying time and esophageal pHimpedance parameters in obese children and adolescents

Objectives and Study: Gastroesophageal reflux disease (GERD) and obesity are currently two of the most common disorders in Western populations. Moreover, a dramatic increase in the incidence of both conditions have been recognized and is expected to continue in epidemic proportions. According to recent evidence, these 2 conditions are likely to be linked, probably due to abdominal higher pressure and junk food eating of obese patients which may trigger GER episodes. Moreover, over the last years a possible role of hormonal factors have been hypothesized to underlie both adult GERD and obesity. The main aim of the present study was to assess the possible association between leptin and ghrelin serum levels and both gastric emptying time and gastro-esophageal reflux disease parameters in obese children. Secondary aims were to assess the relationship between these 2 hormones and obesity compared to healthy children. Methods: We prospectively enrolled obese children and adolescents (4-17 years) complaining from GERD symptoms. A group of age- and sex-matched obese children without GERD symptoms and a group of healthy non-obese children were enrolled in order to obtain comparative data for non-invasive procedures. All the enrolled children underwent auxological examination and completed 2 study questionnaires for the assessment of GER symptoms and quality of life scores. Moreover, all the patients underwent 13-octanoic acid breath test (13C-OABT) to evaluate gastric emptying time and an hormonal dosage of ghrelin and leptin serum levels. Finally, patients with reflux symptoms underwent a 24-hour esophageal pH-impedance recording (MII-pH). Results: 24 obese children with reflux symptoms (M/F: 9/15; mean age ± SD: 134 ± 48 months; range: 48-194 months) were enrolled. 20 obese children without reflux symptoms and 20 non-obese healthy patients were recruited as comparison groups. The T½ gastric half-emptying time was 106.9 minutes among obese symptomatic patients, 116.4 minutes among obese asymptomatic patients, and 114.8 minutes among healthy patients (p>0.05 for all comparisons). The mean leptin blood concentration was significantly higher in both obese symptomatic and asymptomatic patients (198.9 and 251.5, respectively) compared to healthy patients (88.5; p< 0.05 for both comparisons). The mean ghrelin blood concentration was 123.8 among obese symptomatic patients, 123.3 among obese asymptomatic patients, and 289.2 among healthy non-obese patients (p>0.05 for both comparisons). A significative positive association was found between leptin values and: BMI (r:0.72), excess body weight (r:0.62), waist circumference (r:0.84), and narrow waist circumference (r:0.74). Moreover, a significant negative association was found between ghrelin values and BMI (r:-0.63) and between ghrelin values and narrow waist circumference (r:-0.57). No association was found between hormonal levels and MII-pH nor gastric emptying parameters. Conclusion: According to the available evidence, our data confirm that obese patients show higher level of serum leptin and lower levels of serum ghrelin compared to non-obese healthy controls. Nevertheless, no statistically significant association was found among gastric emptying time, GER features and hormonal dosages.