Attributable risks for stomach cancer in northern Italy

The proportions of gastric cancer cases attributable (or attributable risks, AR) to consumption of traditional foods (i.e., pasta, rice and maize), low intake of beta-carotene and vitamin C, short duration of use of an electric refrigerator, low educational level, and family history of gastric cancer were computed using data from a case-control study conducted in Northern Italy. Between 1985 and June 1993 a total of 746 incident, histologically confirmed gastric cancer cases and 2,053 controls admitted to the same network of hospitals for acute, nonneoplastic, non-digestive-tract diseases, unrelated to long-term modifications of diet, were interviewed. The ARs were 48% for low intake of beta-carotene, 40% for high consumption of traditional foods, and 16% for low intake of vitamin C. Overall, these 3 dietary factors explained 73% of the gastric cancer cases in the population. Five percent of all cases were attributable to less than 30 years' use of an electric refrigerator, 15% to low educational level, and 5% to family history of gastric cancer. In individuals over age 60, a greater proportion of cases was attributable to traditional foods, low education and late adoption of electric refrigeration (58% vs. 32% aged under 60), suggesting that correlates of lower social class, influenced lifestyle, and dietary habits more markedly in earlier than in more recent generations. According to our estimates, over 3 quarters of the gastric cancer cases in this area are explainable in terms of the risk factors considered. Increased consumption of vitamin C and beta-carotene, and reduced consumption of traditional foods, would help to avoid over 10,000 out of 14,000 stomach-cancer deaths in Italy every year. Consequently, stomach cancer, which is still the third leading cause of cancer death in Italy, would represent only about 2% of all cancer deaths.