According to a study recently published in the American Journal of Epidemiology, the combination of four risk factors (tobacco use, moderate/heavy alcohol consumption, low income and infrequent consumption of raw fruits and vegetables) accounts for almost all of the squamous cell esophageal cancers in the U.S., with a low annual income being the strongest risk factor.
Esophageal cancer is relatively uncommon, but is one of the most aggressive and deadly of all cancers. In 1998, there were 12,300 new cases of esophageal cancer diagnosed in the United States, and nearly 12,000 deaths occurred. There are two main types of esophageal cancer, adenocarcinoma and squamous cell. Squamous cell is the most common type of esophageal cancer, accounting for more than 80% of all cases. In the United States, esophageal cancer is more common among men, especially black men. Squamous cell carcinoma accounts for over 90% of the esophageal cancers in black men, whereas it accounts for only 50% of those in white men.
In this multi-center study, researchers evaluated the relationship between the risk factors and squamous cell esophageal cancer and the extent to which these risk factors contribute to the higher incidence of esophageal cancer among black men. The researchers collected data from 347 males with esophageal cancer (119 white, 228 black) and compared it with data collected from 1,354 male controls (743 white, 611 black).
The researchers found that the majority of both the white and black males in the study used tobacco, consumed moderate or heavy amounts of alcohol, and consumed a diet low in raw fruits and vegetables. These factors combined with a low income increased the risk of developing esophageal cancer.
The results indicated that individuals with annual incomes below $10,000 had a significantly higher risk for developing esophageal cancer than individuals who had annual incomes of at least $25,000. The risk was higher for low-income black men than it was for low-income white men. White men with annual incomes below $10,000 were 4.3 times more likely to develop esophageal cancer than those earning more than $25,000, whereas black men with annual incomes below $10,000 were 8 times more likely to develop the cancer than individuals in higher income brackets. This increased risk existed even with adjustments for alcohol and tobacco use and infrequent consumption of raw fruits and vegetables.
The results provide valuable information that lifestyle modification, especially reduced alcohol intake, could reduce the risk for developing squamous cell esophageal cancer. The researchers were unsure why low-income black men had a higher risk than low-income white men and speculated that genetic factors may be involved. Typically, individuals in lower socioeconomic groups consume more alcohol and tobacco and eat poorer diets than individuals in higher socioeconomic groups. These individuals also may have limited access to healthcare. More research is necessary to further define the discrepancy between the development of esophageal cancer in white and black men. In the meantime, the results from this study indicate that education will be a valuable tool in encouraging people to make lifestyle modifications to avoid the risk factors.
(American Journal of Epidemiology, Vol 153, No 2, pp. 114-122, 2001)