Cancer of the urinary bladder is the fourth leading type of cancer occurring in men in the United States, but it does occur in women as well. Although the cause of this disease is not completely understood, findings from a recent study indicate that drinking a high volume of fluids each day may reduce the risk of developing cancer of the bladder by 50%.
Cancer of the bladder is characterized by the presence of cancer cells in the bladder, an organ that is located in the lower abdomen and serves to store urine. A person who has 1 or more characteristics, or
risk factors for a type of cancer, has a higher chance to develop that type of cancer than a person who does not have these risk factors. The cause of bladder cancer is not known; however, a few risk factors have been identified. These risk factors include being male, smoking cigarettes, and having exposure to cancer-causing chemicals called arylamines. However, these risk factors likely account for only about half of all bladder cancers. For reasons that are not yet understood, bladder cancer also occurs more frequently in persons of higher socioeconomic groups than in those of lower socioeconomic groups. Researchers have studied many possible factors to explain this difference. There appears to be no clear association between alcohol or coffee consumption and bladder cancer. Some have proposed that public water that is purified may contain cancer-causing chlorinated products, thereby causing a higher incidence of bladder cancer in those who drink it. However, no convincing evidence has emerged to establish drinking purified public water as a risk factor. Now, there does appear to be 1 simple measure to reduce a man’s risk of developing bladder cancer: drinking more fluids.
Researchers at Harvard Medical School evaluated the relationship between total fluid intake and the risk of developing bladder cancer over a 10-year period in almost 50,000 men. During the followup period, 252 men were newly diagnosed with bladder cancer. The lowest incidence of bladder cancer was in men who drank 5 pints or more of fluids per day; the highest incidence was in men who drank less than half a pint (1 cup) per day. Men who consumed more than half a pint but less than 5 pints of fluid had an intermediate incidence of bladder cancer. While the incidence of bladder cancer also increased with older age and cigarette smoking, high fluid intake still had a positive effect in these groups. Indeed, since the incidence of bladder cancer in smokers is 3 to 5 times that in nonsmokers, these persons may benefit the most from increasing their fluid intake.
The conclusions? A high intake of fluids reduces the incidence of bladder cancer by about 50%. All fluids appear to be effective, with no associated differences between types of fluids (water, juice, coffee, alcohol). These findings were not sufficient to make a determination about purified versus non-purified public water. However, it is known that 78% of the participants drank municipal water and comprised 75% of the total bladder cancer incidences. The effects of fluid intake were the same in all regions of the United States; therefore, the researchers concluded that a high intake of water reduces the risk of bladder cancer, regardless of the area of residence. (
New England Journal of Medicine, Vol 340, No 18, pp 1390-1397, 1999)