Long-term weight patterns and risk for cholecystectomy in women

Background: Obesity and rapid weight loss in obese persons are known risk f actors for gallstones. However, the effect of intentional, long-term, moder ate weight changes on the risk for gallstones is unclear. Objective: To study long-term weight patterns in a cohort of women and to e xamine the relation between weight pattern and risk for cholecystectomy. Design: Prospective cohort study. Setting: 11 U.S. states. Participants: 47 153 female registered nurses who did not undergo cholecyst ectomy before 1988. Measurements: Cholecystectomy between 1988 and 1994 (ascertained by patient self-report). Results: During the exposure period (1972 to 1988), there was evidence of s ubstantial Variation in weight due to intentional weight loss during adulth ood. Among cohort patients, 54.9% reported weight cycling with at least one episode of intentional weight loss associated with regain. Of the total co hort, 20.1% were light cyclers (5 to 9 Ib of weight loss and gain), 18.8% w ere moderate cyclers(10 to 19 lb of weight loss and gain), and 16.0% were s evere cyclers (greater than or equal to 20 lb of weight loss and gain). Net weight gain without cycling occurred in 29.3% of women; net weight loss wi thout cycling was the least common pattern (4.6%). Only 11.1% of the cohort maintained weight within 5 lb over the 16-year period. In the study, 1751 women had undergone cholecystectomy between 1988 and 1994. Compared with we ight maintainers, the relative risk for cholecystectomy (adjusted for body mass index, age, alcohol intake, fat intake, and smoking) was 1.20 (95% CI, 0.96 to 1.50) among light cyclers, 1.31 among moderate cyclers (CI, 1.05 t o 1.64), and 1.68 among severe cyclers (CI, 1.34 to 2.10). Conclusion: Weight cycling was highly prevalent in this large cohort of mid dle-aged women. The risk for cholecystectomy associated with weight cycling was substantial, independent of attained relative body weight.