Table 2.

Overall approach to inclusion and exclusion criteria

	Included	Excluded
Publication type	English peer-reviewed journal articles.
Study design	All study designs.
Study population	All studies conducted on security guards of all ages in high-income, middle-income and low-income countries.	Grey literature, unpublished articles, cases and publications that do not have a clear description of methods used. Any data before 1990.
Exposure variables	N/A
Outcome variables	All roles, uses and responsibilities reported by studies.

N/A, not available.