Gallstone disease in a Swedish population : an epidemiological investigation

The main objective of the present thesis was to study the prevalence of gallstone disease in a community survey in Danderyd. Symptoms and risk factors for gallstone disease and the changing incidence of cholecystectomy in Stockholm County was also studied. In a further study plasma levels of lathosterol and 7-a-hydroxy-4-cholestene-3-one was also investigated as circulating markers for the biosynthesis of cholesterol and bile acids. Incidence of cholecystectomy per 100 000 inhabitants 1932-1957 showed an increase from less than 100 to 315 and from 1958-1990 a decrease to 67.

After the introduction of the laparoscopic technique an increase was again noted to a present incidence of 110. Changing indications are believed to be the cause. Acute cholecystectomy had an increasing part of all cholecystectomies and in relation to elective operations increased from 0.15 to 0.40. The prevalence of gallstone disease in 556 randomly selected men and women aged 40 and 60 years was in men 4% and 15%. In women the prevalence was 11% and 25%, in overall 15%. Fifty per cent of subjects with gallstone disease were cholecystectomised. Several symptoms were investigated but there was no single symptom that could predict gallstones in men or women. Subjects already cholecystectomised and patients waiting for elective cholecystectomy had significantly more symptoms than subjects with incidental gallstones.

Common risk factors for gallstone disease were investigated. Heredity was a significant risk factor as relatives to subjects with gallstone disease had known gallstones in 39% compared with 18% in relatives to gallstone free subjects. Obesity was a risk factor for gallstone formation in women but not men. Weight increase since age 20 was a significant risk factor in women but not in men. Parity was a risk factor in women with five or more children (RR 4.05). Duration of fertility period or breast feeding was not a risk factor although increased age of menopause was correlated positively to gallstones. Plasma levels of 7-a-hydroxy-4-cholestene-3-one were not depressed in gallstone subjects but 40% higher. There was no difference in the plasma levels of lathosterol. Hypersecretion of cholesterol in gallstone subjects is not due to a single metabolic defect but rather of multifactorial aetiology.