Risk factors for gall-bladder disease: a cohort study of young women attending family planning clinics

During 1968-74, 17 032 women aged 25-39 years were recruited to the Oxford/Family Planning Association Contraceptive Study. By the end of August 1981, 227 of these women had suffered surgically confirmed gall-bladder disease during the follow-up period, an incidence of 1·47 per 1000 woman-years. Obesity was by far the strongest risk factor for gall-bladder disease, but late age at first term birth and cigarette smoking also had statistically significant independent effects. The influence of the use of oral contraceptives on risk was small.