Japan was included in the Seven Countries Study because of its importantly different diet compared to the American and European diets and its low death rate attributed to CHD. Two rural cohorts were enrolled, one of mainly farmers and another one of mainly fishermen having a very high fish consumption.
The two cohorts of Japan
The cohort of Tanushimaru was made a “chunk sample” of all men of appropriate age residing in the rural village of Tanushimaru, in the island of Kyushu, Japan, a farming community.
The cohort of Ushibuka was made a “chunk sample” of all of men residing in the fishing village of Ushibuka, in the island of Kyushu, Japan, predominantly fishermen with high fish intake.