See “Weight and Reflux: What Is the Relation?” by Dias on page 3.
Gastroesophageal reflux disease (GERD) and obesity are 2 of the most common disorders in Western populations (1). Dramatic increases in the incidence of both conditions have been recognized and are expected to continue in epidemic proportions, suggesting a possible link between the 2 disorders.
The obesity epidemic involves both adults and children and is spreading across lines of race, sex, and socioeconomic status (2,3). Rates of overweight and obesity among children have more than doubled in the last several decades, with the most recent estimates indicating that approximately 30% of children are overweight or obese (4,5).
GERD is a common condition, defined by the passage of gastric contents into the esophagus, causing troublesome symptoms and/or complications, affecting up to 20% of the general population (6). In adult populations, several cross-sectional studies have demonstrated a positive association between high scores of body mass index (BMI)—the weight in kilograms divided by the square of the height in meters—and symptoms of GERD (7–14). Data on the association between GERD and obesity in children are scarce and inconclusive. The few studies performed in children analyzed only the relation between reflux symptoms and total body fatness, measured by BMI (15,16). Recent studies have found that central adiposity, measured by the waist circumference (WC), may be more important than BMI in the pathogenesis of GERD.
The relation between GERD symptoms and central body fatness, measured by the WC, is supported by limited data in adults and has never been investigated in children. The aims of our study were to evaluate the prevalence of GERD symptoms in overweight and obese children in comparison with a general normal-weight pediatric population and whether the GERD symptoms are associated with the WC.
We prospectively enrolled all of the consecutive children between 2 and 18 years old referred to the Primary Care Center of the Department of Pediatrics, University “Federico II,” Naples, Italy, for routine well-child visits, from June 2009 to December 2009. A detailed clinical history and physical examination, including determination of height, weight, BMI, and WC, were obtained from each patient. Based on standards of practice that reflect Institute of Medicine definitions, participants were categorized according to BMI as underweight (BMI <5th percentile), normal-weight (BMI from 5th to 85th percentile), overweight (BMI from 85th to 95th percentile), and obese children (BMI >95th percentile), and according to WC in children with WC <75th percentile, from 75th to 90th percentile, and >90th percentile (17–19). When necessary, minimal laboratory tests were performed.
During the clinic visit, children's esophageal symptoms (heartburn, epigastric pain, vomiting and regurgitation, irritability with meals, dysphagia and/or odynophagia, respiratory symptoms, and hematemesis) during the preceding 2 months were recorded using a standardized questionnaire. Considering that validated questionnaires for the assessment of reflux symptoms in children are not available, we decided to use a scale that was already used in previous articles (20,21). The severity of symptoms was classified as follows: grade 0, no symptoms; grade 1, mild symptoms with spontaneous remission and no interference with normal activity or sleep; grade 2, moderate symptoms with spontaneous but slow remission and mild interference with normal activity or sleep; grade 3, severe symptoms without spontaneous remission and marked interference with normal activity or sleep. The frequency of symptoms was classified as follows: grade 0, absent; grade 1, occasional (symptoms present <2 days per week); grade 2, frequent (symptoms present 2–4 days per week); and grade 3, very frequent (symptoms present >4 days per week). A score for each symptom and a total symptom score were calculated. The score for each symptom was calculated by multiplying the severity grade by the frequency grade, with a possible range for each score of 0 to 9. The total symptom score (range 0–57) was calculated by adding up the scores for each symptom.
Subjects were excluded if they had symptoms or findings suggestive of physical disease (eg, abnormal physical examination or laboratory findings, constitutional symptoms such as fever or weight loss), acute or chronic illnesses that may cause gastrointestinal symptoms, or a history of major abdominal surgery.
The experimental design was previously approved by the independent ethics committee of the University “Federico II” of Naples, and informed consent was obtained from parents of all of the children younger than 10 years and from both parents and children, if the children were older than 10 years.
All of the data were statistically analyzed using the Fisher exact text and the χ2 test, when appropriate. Two-sided P values of <0.05 were considered to indicate statistical significance. Statistical analysis was performed with SPSS software, version 8.0 (SPSS Inc, Chicago, IL).
One hundred fifty-three patients (75 boys and 78 girls; mean age ± standard deviation (SD) 8.17 ± 4.15 years; range 2–17.7 years) were enrolled in the study. The mean BMI score ± SD was 19.1 ± 5.6, and the mean WC ± SD was 62.9 ± 17.2 cm. Esophageal symptoms in the previous 2 months were recorded from each patient, obtaining a total reflux symptomatic patient score. Forty-nine of 153 patients (32%) complained of at least 1 symptom of GERD. The prevalence of GERD symptoms in the different study groups is shown in Table 1. The total mean reflux score was 1.3.
Among the 153 subjects investigated, 31 (20.3%) were obese, 28 (18.3%) were overweight, 87 (56.8%) were normal weight, and 7 (4.6%) were underweight. No significant differences by age and sex were noted among the different groups of BMI. The distribution of GERD symptoms and the mean reflux scores in the different groups of BMI are shown in Table 2.
Reflux symptoms were significantly more frequent in obese than in normal-weight children (61.3% vs 21.8%, respectively; P < 0.005) and reflux symptomatic score resulted significantly higher (average score 2.9 vs 0.83, respectively; P < 0.005). A trend toward a higher rate of reflux symptomatic score was present in overweight patients compared with normal-weight children (average score 1.15 vs 0.83, respectively; P = 0.07). A direct relation was observed between increasing BMI and reflux symptoms. This relation continued across all of the categories of BMI >25th percentile (Fig. 1).
Among the 153 subjects investigated, 29 (19%) had a WC >90th percentile, 24 (15.7%) had a WC from the 75th to the 90th percentile, and 100 (65.4%) had a WC <75th percentile. Age and sex distributions in the different groups of WC were similar. The distributions of GERD symptoms and the mean reflux scores in the different groups of WC are shown in Table 3.
There was a significant association between prevalence and severity of reflux symptoms, and WC >90th percentile: children with WC >90th percentile were more likely than children with WC <75th percentile to complain about reflux symptoms (62% vs 24%, respectively; P < 0.005) and had a reflux symptomatic score significantly higher (average score 3.1 vs 0.84, respectively; P < 0.005). A trend toward a higher rate of reflux symptomatic score was present in the group with WC from 75th to 90th percentile compared with the group with WC <75th percentile (average score 1.06 vs 0.84, respectively; P = 0.09). This positive trend continued across all of the categories of WC >25th percentile (Fig. 2).
In the present study we found a strong positive association between obesity and GERD symptoms in a large cohort of children. This association extended across all of the categories of BMI >25th percentile, suggesting that the risk of symptoms rises with BMI in both normal-weight and overweight children.
Our preliminary findings increase a growing body of literature addressing the association between BMI and GERD. In adults, the link between these 2 conditions has been debated for decades, with the majority of the evidence suggesting a direct relation between obesity and GERD.
Our study provides an important evidence to the assertion that obesity is a risk factor for symptoms of GERD also in children and further extends those findings by showing that the risk of developing GERD symptoms appears to be directly linked to BMI, regardless of whether a child is of normal weight or is overweight. This suggests that moderate amounts of weight gain, even among normal-weight children, may result in the development or exacerbation of GERD symptoms. This is of particular concern considering the recent trend of rising BMI in Western populations among both adults and children (2,3).
The second important finding of our study is that there is a positive association between GERD symptoms and high values of WC in children. This association, already demonstrated in adults, has not been reported in children (21). WC is a simple-assessing index of abdominal obesity. Even though recent recommendations of expert committees suggest that BMI not be replaced with WC for clinical diagnostic purposes, great interest has been raised in the role played by abdominal obesity. To our knowledge, we are the first to establish the importance of central adiposity, measured by the WC, in the development of reflux symptoms in children.
In conclusion, our study shows that total and abdominal obesity are independent risk factors for reflux symptoms in children. The risk of GERD symptoms seems to rise progressively with increasing BMI and WC, even among normal-weight children. Our findings have important implications for future studies, which are asked to confirm, by the use of objective parameters such as impedance measurements, that even moderate weight gain may cause or exacerbate reflux symptoms. In addition, in children with GERD symptoms, the evaluation of WC should be routinely performed and its reduction should be strongly recommended.
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