The prevalence of reflux esophagitis in Korea has increased since the 1990s. In 1999, the prevalence of reflux esophagitis in patients with gastrointestinal symptoms was 5.3%.26
The prevalence of erosive esophagitis in patients undergoing regular health check-up was 8.0% in 2006.7
In this study, the prevalence of reflux esophagitis was 8.8%, which is similar to the previous study.
Seroprevalence of H. pylori
were 59.5% and 59.8% in 2005 and 2011, respectively. The relationship between H. pylori
and reflux esophagitis is not clear yet. In a recent large case-control study, H. pylori
seropositivity was inversely associated with the risk of reflux esophagitis, and the prevalence of H. pylori
infection was lower in reflux esophagitis cases than in controls (38.4% vs. 58.2%, P
In our large sample, the prevalence of H. pylori
infection was also lower in reflux esophagitis cases than in patients without reflux esophagitis (44.6% vs. 61.3%, P
< 0.0001) and the OR of H. pylori
seronegativity for the development of reflux esophagitis was 1.91 (95% CI, 1.48-2.46). H. pylori
infection was inversely correlated with the risk of erosive esophagitis.
The association between H. pylori
seropositivity and residence location is well known.21
According to geographic area in 2005, seroprevalence was 57.6% and 60.5% in big cities (Seoul and Gyeonggi, respectively), while higher than 60% in small and medium cities. The seroprevalence of H. pylori
between 2005 and this study was not changed in big and small-medium cities. Differences in socioeconomic condition, sanitation and hygienic practices may explain this result. Taken together, the seroprevalence was slightly lower in big city residence than small and medium sized cities, suggesting that this difference could not explain the different prevalence rate of erosive esophagitis according to dwelling status.
Asides from H. pylori
infection, obesity is an another major risk factor for erosive esophagitis.27,28
However, recent studies on the association between BMI and erosive esophagitis have resulted in heterogenous data.29-32
There are no large-scale prospective studies involving healthy subjects with erosive esophagitis in the aspect of dwelling places. Relationship between obesity and erosive esophagitis is well known,28
however, the gender effect is controversial.33-35
Our study showed that rate of obesity in big city dwelling was less frequent than that in small and medium cities after adjusting for potential confounding factots. According to KNHANES obseity data from 1998 to 2009 (1998, 2005 and 2007-2009), Korean with a BMI ≥ 25 kg/m2
was found to be 25.9%, 34.8% and 35.8% in men, 27.5%, 28.3% and 26.1% in women, respectively.22
This result suggests that the prevalence of obesity was recently stagnated, and that there is a decreasing tendency in women. Our study shows that the prevalence rate of erosive esophagitis was lower in big city dwelling than in small and medium cities dwelling (7.1% and 9.4%, respectively) due to less frequent rate of obesity (P
< 0.001) and these data were obtained after adjusting for confounding factors, including H. pylori
infection, TG, glucose and hiatal hernia. This lower rate of BMI ≥ 25 kg/m2
in big city residence may be explained by the fact that they may have a chance to receive a regular private health screening and engage in regular exercise maintaining a healthy weight.
Many other studies have found that hiatal hernia is associated with a high risk of reflux esophagitis.36-39
In our study, according to univariate analysis hiatal hernia (OR, 3.02; 95% CI, 1.87-5.16) was significantly associated with reflux esophagitis (all P
Factors that are consistently reported to be associated with reflux esophagitis include advanced age, diabetes, hyperlipidemia, alcohol and smoking.19,40-45
In the present study, multivariate analysis identified high TG (OR, 1.65; 95% CI, 1.08-2.07) and elevated fasting glucose (OR, 1.73; 95% CI, 1.06-2.81) level as risk factors. Reports of the effects of smoking and alcohol consumption on the development of reflux esophagitis have been inconsistent.44,45
In our study, according to univariate analysis alcohol consumption (OR, 2.19; 95% CI 1.74-2.76) and smoking habit (OR, 1.66; 95% CI, 1.28-2.16) were significantly associated with reflux esophagitis (all P
The present study has several potential limitations. First, 527 (13.1%) patients with H. pylori eradication were included. The reasons for eradication were peptic ulcers (24.9%), gastroduodenitis (33.7%), patients' choice (35.9%) and family history of gastric cancer (2.6%). However, these subjects were equally distributed among cases and controls and there was no statistically significant difference between patients with and without reflux esophagitis, with respect to H. pylori eradication. Second, H. pylori infection status was evaluated only by serologic testing. Therefore, we did not assess the current or past infection status. Third, analysis of risk factors did not take into account the severity of reflux esophagitis.
In conclusion, the prevalence rate of erosive esophagitis and its risk factors in this study were similar to nationwide study in 2006. H. pylori seropositivity and residence in a large city were inversely related to the risk of reflux esophagitis in a large-sample, multicenter study of the Korean population. The degree and duration of obesity would be important risk factor for the development of erosive esophagitis in the future. Factors associated with metabolic syndrome including high TG and elevated fasting glucose level and hiatal hernia were also related to the risk of reflux esophagitis.
This study is meaningful in that as it has provided clues regarding the prevalence of erosive esophagitis and risk factors in healthy subjects. Further studies are necessary to determine the potential risk factors for the development of erosive esophagitis and we should pay attention to the changes in the prevalence of obesity in Koreans.