Introduction

 

The incidence of peptic ulcers has fluctuated considerably in the past. There was a rapid increase in its prevalence at the turn of the 20^th century in the western countries. This has been followed by a notable decline in their incidence and prevalence over the past four decades,1,2,3 This decreasing trend is noticeable in the Asia-Pacific regions also.4,5,6,7,8

 

Studies in the past have shown that the occurrence of peptic ulcer disease has been influenced by seasonal changes, with a trend towards an increased incidence in the winter months.9,10,11 However, in a recent study, the time trends of neither endoscopic procedures nor endoscopic diagnoses revealed any seasonal variation or other cyclic pattern.12

 

Studies on time trend of peptic ulcer disease are not available from the Indian subcontinent. The purpose of this study was to identify changing trends in the occurrence of peptic ulcer with regard to the frequency, mean age of occurrence and  gender specificity over a period of 16 years. It also aimed at testing the hypothesis that the diagnosis of duodenal and gastric ulcer at endoscopy may be influenced by change in the season.

 

Methods

 

In a retrospective study, the endoscopy records between the years 1989 and 2004 at our institution, which serves as a tertiary referral centre in Chennai were reviewed.

 

Individuals with an endoscopy diagnosis of duodenal or gastric ulcer or a combination of the two in a background of ulcer type dyspepsia were included for the study. Incidental detection of gastric or duodenal ulcer in cirrhosis of liver, post  gastric surgery and upper GI malignancies were excluded. Details of age, gender, duration of symptoms, month and year of procedure, presence of duodenal or gastric ulcer or a combination, deformities in the pylorus and duodenum (deformed bulb) and presence of gastric outlet obstruction (GOO) were noted from the records. Gastric ulcers were classified based on the location as: Type I: ulcer in lesser curve incisura; Type II: prepyloric ulcer; Type III: gastric ulcer with duodenal ulcer; Type IV: Juxtacardiac gastric ulcer and Type V: Gastric ulcers in multiple sites.13,14,15

 

Seasonal variations were also noted. The climate of city of Chennai, located in the southern part of the Indian subcontinent, is for most of the months uniformly hot and humid. The months between November to February are pleasant with December and January being the coolest with less humidity. The monsoon season is from October to mid- December.

 

Statistical Analysis

 

Statistical analysis was performed using the chi-square test, one way ANOVA and Student t-test wherever appropriate. P value less than 0.05 was considered significant.

 

For the analysis of seasonal variation, each year was divided into 4 quarters (January-March, April-June, July- September & October-December) corresponding to the seasons. The raw data were plotted versus the month of endoscopy. Endoscopic diagnoses were then expressed as proportional rates per 100 endoscopies and procedural month. The study period (1989-2004) was divided into 4 groups (1989- 92, 1993-96, 1997-2000 & 2001-4) and proportional rates were calculated for each quarter (e.g. Jan-Mar) for the 4 groups respectively. 3-month moving averages were then calculated for each quarter and the seasonal index was derived as the mean of the 3 - month moving averages. Adjusted seasonal index was then calculated by adjusting the mean of the seasonal indices to 100.

 

Results

 

During the study period, 7365 patients had duodenal ulcer, 2834 patients had gastric ulcer (including the 1605 patients who had a combination of DU and GU), out of a total of 60205 endoscopy procedures.

 

Age and gender specific trends

 

Duodenal ulcer

 

Among all the duodenal ulcers diagnosed during the study period, those with (43.84%) and without (46.89%) features of chronicity were equally prevalent. Gastric outlet obstruction (9.26%) was relatively uncommon (Table 1). The overall mean age of patients with duodenal ulcer was 39.1 ± 13.46 years.

 

On gender specific analysis, there was no significant difference in the mean age of endoscopic diagnosis of DU between males and females (Table 2). An increase in the mean age of endoscopic diagnosis was noted across the four cohorts with regard to duodenal ulcers overall, DU without chronicity and DU with deformed bulb. A similar trend was observed among men and only for DU with deformed duodenal cap among women on gender specific analysis. No significant changes were seen with regard to DU with gastric outlet obstruction – overall and on gender specific analysis (Table 3).

 

DU and all its subtypes occurred more commonly among men than women in all the four cohorts. However, over the years the proportion of women affected showed a significantly increasing trend with regard to duodenal ulcers overall and  specifically for those ulcers with a deformed bulb. A similar trend was observed in patients with DU without chronicity, though levels of statistical significance were not reached (p = 0.08) (Figure 1).

 

Gastric ulcer

 

Among the gastric ulcers diagnosed during the study period, type III ulcers were the most common (Table 1). The mean age of diagnosis of gastric ulcer overall was 44.30 + 14.40 years.

Over the 16-year period, there was a significant increase in  the mean age of endoscopic diagnosis of GU (Overall, i.e. including all the five subtypes) and for subtypes II and III. A similar trend was observed among men. Among women, there was an increase in the mean age of occurrence of GU (Overall) and type II GU (Table 3). On gender specific analysis, women presented at a significantly younger age than men for types I and V gastric ulcers (p values of 0.02 and 0.001 respectively) (Table 2).

 

On gender specific analysis, GU and all its subtypes occurred more commonly among men than women in all the four cohorts. Over the years, there was an increase in the proportion of women affected by GU (overall) and for types II and III (Figure 2).

 

Time trends of ulcer diagnosis

 

There was a significant decrease in the endoscopic diagnosis of DU, GU and their subtypes over the years. The trend towards a decline started during the third cohort (1997-2000), though the number of endoscopies performed did not show any significant change (Table 1).

 

Seasonal index

 

The adjusted seasonal index, calculated for the endoscopic diagnosis of gastric ulcer and duodenal ulcer, showed a higher frequency of diagnosis of DU and GU during the relatively cooler months of October – March (Figure 3).

 

Discussion

 

The incidence of peptic ulcer disease has shown a fluctuating trend in the past. In the West, the incidence of peptic ulcer, particularly duodenal ulcer, rose sharply at the turn of the 19^th  to the 20^th century but has declined considerably in the past three decades.[1,2] In the East, the rise was equally impressive, but the decline appears to have been delayed; only starting in the past decade.[4,5]

 

The present study focused on the trends in the endoscopic diagnosis of duodenal ulcers with its complications and also the gastric ulcer, over a period of 16 years with a total of 60,205 endoscopic procedures, from a tertiary referral centre in a southern state of the Indian subcontinent.

 

There was a significant trend towards an overall decrease in the endoscopic diagnosis of duodenal ulcers including its complications. A similar decreasing trend was observed for the endoscopic diagnosis of GU. This is consistent with observations from the west as well as from some Asian countries.[4,5,6,7] The declining trend has been attributed to an improvement in sanitation and hygiene resulting in a decrease in the rate of Helicobacter pylori infection and the widespread use of proton pump inhibitors.[3, 8]

 

Over the years, a greater proportion of females were found to have an endoscopic diagnosis of DU and GU. Also, the  mean age of an endoscopic diagnosis of DU and GU has shown a steady increase during the study period. In the west, though  there was a decline in the hospital admissions and mortality from peptic ulcer for most age groups between 1950-80[16,17]; admissions for perforated peptic ulcer and mortality from duodenal ulcer increased among elderly, especially women between the 1970s and 1980s.[17,18,19] Even in the era of proton pump inhibitors, admission rates for gastric and duodenal ulcer haemorrhage and duodenal ulcer perforation has increased among older subjects.[20] The rise in mortality and admissions among older women in the 1970s and 1980s has been attributed to the increased prescription of nonsteroidal anti-inflammatory drugs, the other major cause of peptic ulcer, in older subjects.[21]

 

Studies in the past have shown that the time trends of gastric and duodenal ulcers are influenced by an underlying seasonal variation.[9] The occurrence of peptic ulcer is characterized by a winter high and a summer low.[10,11,12] The exact cause for this seasonal variation is unknown. It could be because viral infections and pneumonias that usually occur in winter may make the patients more susceptible to other diseases. Another reason could be that patients are less exposed  to health care during the summer months because of vacations resulting in fewer encounters with physicians.[22,23,24] However, a recent U.S study based on a large database from several centers showed that the time trends of neither endoscopic procedures nor certain endoscopic diagnoses (such as duodenal ulcer and colorectal cancer) revealed any seasonal variation or other cyclic pattern.[12] In the present study, from the Indian subcontinent where a seasonal variation does not occur for most of the year, it was observed that the endoscopic diagnosis of duodenal or gastric ulcer was lower in the months between April to September and relatively higher between October to March.

 

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