A new possible pathogenesis of some gallstones

Prevalence and ethnic differences in gallbladder disease in the United States

BACKGROUND & AIMS

Gallbladder disease is one of the most common conditions in the United States, but its true prevalence is unknown. A national population-based survey was performed to determine the age, sex, and ethnic distribution of gallbladder disease in the United States.

METHODS

The third National Health and Nutrition Examination Survey (NHANES III) conducted gallbladder ultrasonography among a representative U.S. sample of more than 14, 000 persons. The diagnosis of gallbladder disease by detection of gallstones or cholecystectomy was made with excellent reproducibility.

RESULTS

An estimated 6.3 million men and 14.2 million women aged 20-74 years had gallbladder disease. Age-standardized prevalence was similar for non-Hispanic white (8. 6%) and Mexican American (8.9%) men, and both were higher than non-Hispanic black men (5.3%). These relationships persisted with multivariate adjustment. Among women, age-adjusted prevalence was highest for Mexican Americans (26.7%) followed by non-Hispanic whites (16.6%) and non-Hispanic blacks (13.9%). Among women, multivariate adjustment reduced the risk of gallbladder disease for both Mexican Americans and non-Hispanic blacks compared with non-Hispanic whites.

CONCLUSIONS

More than 20 million persons have gallbladder disease in the United States. Ethnic differences in gallbladder disease prevalence differed according to sex and were only partly explained by known risk factors.

Fair, and still a sun lover: risk of gallstone formation

STUDY OBJECTIVE

The aim was to evaluate the hypothesis that sunlight exposure leads to the development of gallstones in people with a sun sensitive skin.

DESIGN AND SETTING

This was a case-control study among 206 white patients referred for an ultrasound examination of the gallbladder. Sunlight exposure and skin sensitivity were retrospectively assessed by a structured questionnaire. The questionnaire was taken before the outcome of the ultrasound examination was known, so that the patients and the interviewers were blind to the outcome. The main outcome measure was gallstones in the gallbladder detected by ultrasound.

MAIN RESULTS

87 patients had gallstones (cases), 119 had none (controls). In subjects with a skin sensitive for sun (Fitzpatrick skin type I) a positive attitude to sunbathing was associated with a higher risk of gallstones than a negative attitude. In subjects with an insensitive skin (skin type IV) no association was found.

CONCLUSIONS

This study confirms a hypothesis which was based upon metabolic research. However it is too early to upgrade the first "F" in the traditional adage that gallstone patients are "fair, fat, female, fertile and forty". Since both epidemiological and pathobiological evidence is scarce, the role of sun and/or (ultraviolet) light exposure and skin sensitivity in the aetiology of gallstones should be confirmed by further research.

Chromatography of urinary indole derivatives

Latest strategies are discussed for the routine chromatographic analysis of clinically important indole derivatives in urine. Analysis of 5-hydroxyindoleacetic acid and, perhaps more importantly, serotonin and 5-hydroxytryptophan remains attractive in the screening for carcinoid tumours and their differentiation. Analyses of two precursors of the skin pigment eumelanin seem to be promising in the monitoring of treatment of malignant melanoma and screening for pigmentation disorders and gallstone formation. Studies on the clinical relevance of the determination of tetrahydro-beta-carbolines and melatonin-related indoles await routine application of chromatographic methods designed to take into consideration the relative instability of these compounds. Application of GC-MS, although confined to larger and/or governmental laboratories remains attractive as a way of improving the specificity of analyses and in establishing reference methods. As for HPLC, the recent development of chromatographic and detection methods for the concurrent determination of different clinically important and metabolically related compounds from the same sample, preferably by direct injection techniques, seems to be fruitful and should be continued.