Reexamination of total fluid intake and bladder cancer in the Health Professionals Follow-up Study Cohort

Abstract

It has been hypothesized that high fluid intake may reduce contact time between carcinogens and bladder epithelium and consequently reduce carcinogenesis. Epidemiologic studies examining fluid intake and bladder cancer have been extremely inconsistent, ranging from strong inverse to strong positive associations. The authors reevaluated the association between fluid intake and bladder cancer among 47,909 participants in the prospective Health Professionals Follow-up Study over a period of 22 years. During follow-up (1986-2008), 823 incident bladder cancer cases were diagnosed. Information on fluid intake was collected by using the food frequency questionnaire at baseline and every 4 years thereafter. Cox proportional hazard regression analysis was used to adjust for risk factors for bladder cancer. Total fluid intake was inversely associated with bladder cancer when the analysis was based on the baseline diet (relative risk = 0.76, 95% confidence interval: 0.60, 0.97), comparing the highest total daily fluid intake quintile (>2,531 mL/day) with the lowest quintile (<1,290 mL/day) (P(trend) = 0.01). However, no association was detected when the analysis was based on recent diet or cumulative updated diet. The updated analysis for total fluid intake and bladder cancer was attenuated compared with the original findings from the first 10-year follow-up period.

Figure 1.

Average daily fluid consumption in the Health Professionals Follow-up Study, 1986–2008. Fruit juice includes tomato or V8 juice, carrot juice, prune juice, apple juice or cider, orange juice, grapefruit juice, and other fruit juices. Coffee includes decaffeinated coffee and coffee with caffeine. Soda includes low-calorie carbonated beverages with caffeine (e.g., Diet Coke, Diet Mountain Dew), other low-calorie carbonated beverages without caffeine (Diet 7 Up), carbonated beverages with caffeine and sugar (Coke, Pepsi, Mountain Dew, Dr Pepper), and other carbonated beverages with sugar (e.g., 7 Up, root beer, ginger ale). Milk includes skim milk, 1% or 2% milk, whole milk, and soy milk. Water includes plain water (bottled, sparkling, or tap). Other drinks include punch, lemonade, other noncarbonated fruit drinks, sugared ice tea, regular beer, light beer (e.g., Bud Light), red wine, white wine, liquor (vodka, gin, etc.), herbal tea or decaffeinated tea, and tea with caffeine. Registered brands include V8 juice (Campbell Soup Company, Camden, New Jersey); Coke and Diet Coke (The Coca-Cola Company, Atlanta, Georgia); Diet Mountain Dew, Mountain Dew, and Pepsi (Pepsico, Inc., Purchase, New York); Diet 7 Up, 7 Up, and Dr Pepper (Dr Pepper Snapple Group, Plano, Texas); and Bud Light (Anheuser-Busch, St. Louis, Missouri).