我が国の胃がん死亡と摂取栄養因子の疫学的研究

The aim of this study is to assess the effects of dietary factors on the death from stomach cancer in Japan. We analyzed the correlation between socioeconomic factors and age-adjusted death rate (ADR) from stomach cancer for every five year and that between mean intake of food or nutrient during two periods (former period : 1966-1970, latter period : 1976-1980) and the reduction rate in ADR from stomach cancer for two periods (former period : 1966-1980, latter period : 1976-1990). Moreover, principal component analyses of food intake for two periods were performed to examine the changes in the structure of food intake and its correlation with the reduction rate in ADR from stomach cancer.
There were significant positive correlations between the reduction rate in ADR from stomach cancer and some socioeconomic factors (total expense for food, consumpion of alcoholic beverages and consumption of salted and dried fish). There were significant negative correlations between ADR from stomach cancer and several food or nutrient intakes (wheat and egg intake for former period, milk and animal fat intake for latter period) (p<0.01). The reduction rate in ADR from stomach cancer were greater in districts where these food or nutrient intakes were larger. On the other hand, there were positive correlations between the reduction rate in ADR from stomach cancer and some food or nutrient intakes (rice intake for former period, beans intake and the P/S ratio for latter period) (p<0.05). The reduction rate in ADR from stomach cancer were smaller in districts where these food or nutrient intakes were larger. Principal component analyses revealed that the intakes of foods used in traditional Japanese diet were identified as first principal component for both former and latter periods. As second principal component, food intakes related to the Western diet were identified. During the former period, the reduction rate in ADR from stomach cancer had a significant positive correlation with the fist principal component (p<0.05). On the other hand, during the latter period, a significant negative correlation was obtained between the reduction rate in ADR from stomach cancer and the second principal component.
These results indicate that westernization of the Japanese style diet, while preserving its major traditional features, is related to both the reduction and regional differences in deaths rate from stomach cancer in Japan.