International comparison of the definition of night work - Promoting health care of shift workers

In order to manage occupational exposure, it is necessary to define exposure. In terms of administrative management however, shift work is difficult to define because there is a wide variance of working schedules which do not belong to ordinal day time work. Thus, many countries define night work, which is easier to define based on night working time for administrative management, rather than shift work. On the other hand, the term "night work" has not been so common in medical research compared to the term "shift work". Further, those two words were used in nearly same context among medical researchers in many cases. Given the current situation, for the purpose of promoting occupational health, it is reasonable to treat those two medical and administrative words as synonymous in order to make full use of medical evidence with linkage to the current administrative system.