There is a much longer answer to that question. SK and Japan only make up 5% of the asian population, many parts of asia are not well tested for these drugs. We're actually in the process of working with a large pharmaceutical company on a multi-country diabetes prevention trial in Asia because traditionally they have not been tested on as much as necessary. As well the companies there will run many of their trials in the US as well as Asia but our larger population (as well as running the trials in mostly white continents such as Australia and Europe) still causes quite a large discrepancy. We could do a whole other article on this topic.
Japan retests, and interestingly recreates the same problems in a local way.
Taking medical checks for foreigners or minorities in japan means the guidance numbers are mostly irrelevant. Doctors might not know very well how to deal with you, a lot of advice for common but non critical illness can be summed up to “you do you”