Lifestyle risk factors for intrahepatic stone: findings from a case-control study in an endemic area, Taiwan.

Background And Aim: To examine associations between lifestyle risk factors and intrahepatic stone (IHS), we conducted a case-control study in Taiwan, which has the highest incidence of IHS in the world.

Methods: Study subjects were 151 patients newly diagnosed with IHS at Chang Gung Memorial Hospital between January 1999 and December 2001. Two control subjects per case were selected randomly from patients who underwent minor surgery at the same hospital and from family members or neighbors of the hospital staff. Controls were matched to each case by age and gender. Information on lifestyle factors was collected using a self-administered questionnaire. Strength of associations was assessed using odds ratios derived from conditional logistic models.

Results: Female patients were significantly shorter than female controls. Compared to subjects with two or fewer children, odds ratios for those with six or more children were 20.4 in men (95% confidence interval, 1.89-221) and 2.82 (0.97-8.22) in women. Increasing level of education lowered the risk of intrahepatic stone (trend P = 0.004 for men and < 0.0001 for women). Women who had consumed ground-surface water for a long period had a somewhat increased risk (trend P = 0.05).

Conclusion: Lower socioeconomic status and poor hygiene may be involved in the development of intrahepatic stones.