Ningen Dock: Japan's unique comprehensive health checkup system for early detection of disease.

Japan's comprehensive health checkup - Ningen Dock - is a unique system for early detection of disease that has developed over the years along with the country's universal health insurance system. Ningen Dock is currently offered at 1,727 facilities nationwide, involving about 3.7 million people annually. The development of the comprehensive health checkup system may be one reason for Japan's long life expectancy. The major purpose of the comprehensive health checkup system is to maintain health in three main ways: early detection of cancer, detection of lifestyle-related diseases, and confirmation of health status. Here, the history and current status of Ningen Dock in Japan, tests and examinations included in the comprehensive health checkup system, the effectiveness of those checkups, and their advantages and disadvantages are described.