Prevalence: A gallstones survey limited to railroad workers conducted in 1966 utilizing oral cholecystography had suggested that gallbladder stones occurred 7 times more commonly in North Indian workers than in South Indian workers¹. This difference was attributed to the different ethnic backgrounds of the workers. Delhi being a cosmopolitan city has inhabitants from different parts of the country living often in colonies comprised mostly of their own ethnic groups. This provided us an excellent opportunity to study the prevalence of gallstones in Delhi, each with inhabitants belonging to a specific ethnic group (Table 1). The study comprised a short clinical history and examination, a dietary history on a pre-formed questionnaire and an abdominal ultrasound examination. Of a total of 1104 subjects examined, 48 (4.3%) were found to have gallbladder stones². This prevalence figure is about half of that in the western world (10%). The most interesting feature however, was that the gallstone prevalence varied tremendously between our different ethnic groups, the highest being in Punjabis (North Indians) and the lowest in South Indians (Table 1). Besides ethnic influence, dietary differences might also be responsible for this wide variation in gallstone prevalence. However, the number of subjects studies and the design of this study did not permit us to differentiate between these two etiological factors.

Composition of gallstones and bile: In order to establish the type of gallstones, we obtained gallstones from 46 consecutive patients who underwent cholecystectomy at our hospital. On chemical analysis, 28 (61%) of them were found contain >70% of their dry weight as cholesterol, thus qualifying to be cholesterol stones and 9 of them (19.5%) had <20% of their dry weight as cholesterol, thus qualifying them to be labeled as pigment stones. The remaining 9(19.5%) gallbladder stones had their cholesterol content midway between the two groups; we labeled them as "intermediate" cholesterol stones². Bile lipid estimations however clarified that the latter group of stones as well as the cholesterol predominant stones were associated with cholesterol supersaturation of bile whereas pigment gallstones were associated with biles of normal or undersaturation with cholesterol.

Oral dissolution of gallstones: To find out if our cholesterol predominant gallbladder stones responded to oral dissolution, we inducted 132 patients with radiolucent gallstones in a prospective study. Each patient was given 10 mg/kg of ursodeoxycholic acid in three divided doses. Within a period of 1 year, 65 patients lost their gallstones. Another set of 32 patients had mild to moderate reduction in stone size whereas the remaining 25 patients had no effect on the size of their stones.

Conclusion: The prevalence of gallbladder stones varies widely in different communities in India, the North Indians having 2-4 fold higher prevalence as compared with those among South Indians. Furthermore, there is a predominance of cholesterol gallstones among the North Indians and these stones are amenable to dissolution with ursodeoxycholic acid.

Table 1: Gallstone prevalence in 4 different communities in New Delhi.

N = number of subjects studied

1. Malhotra SL. Epidemiological study of cholelithiasis among railroad workers in India with special reference to causation. Gut 1968;9:290-5.

2. Tandon RK. Studies on pathogenesis of gallstones in India. Ann Natl Acad Med Sci (India) 1989;25:213-22.