CIGARETTE-SMOKING AND PARITY AS RISK-FACTORS FOR THE DEVELOPMENT OF SYMPTOMATIC GALL-BLADDER DISEASE IN WOMEN - RESULTS OF THE ROYAL-COLLEGE OF GENERAL-PRACTITIONERS ORAL CONTRACEPTION STUDY

The effects of cigarette smoking and parity on the development of symp tomatic gall bladder disease remain controversial. These relations hav e been examined in a cohort of 46 000 women followed for up to 19 year s during the Royal College of General Practitioners' (RCGP) oral contr aception study. During follow up, 1087 women were recorded as experien cing their first ever episode of symptomatic cholelithiasis (Internati onal Classification of Diseases, 8th revision (ICD-8) 574) or cholecys titis (ICD-8 575). Smokers were more likely to develop symptomatic gal l bladder disease than non-smokers (relative risk 1.19; 95% confidence intervals (95% CI) 1.06 to 1.34) and there was a significant trend wi th the number of cigarettes smoked daily (test for trend chi(2)=7.58, p<0.01). This relation was most apparent among never users of oral con traceptives,, although similar trends were found among current and for mer users. A significant direct relation between symptomatic gall blad der disease and parity was also found (test few trend chi(2)=21.89, p< 0.001). When all were examined together a trend of increasing risk wit h lower social class was also found (test for trend chi(2)=5.72, p=0.0 2). Current users of oral contraceptives had a moderately increased ri sk of symptomatic gall bladder disease (relative risk 1.15; 95% CI 0.9 9 to 1.34), unlike former users (relative risk 1.03; 95% CI 0.90 to 1. 18). These results suggest that smoking and parity are important risk factors for the development of symptomatic gall bladder disease in wom en.