Almost all of the identified quantitative studies use multivariate statistical techniques and control for participants basic demographic characteristics. Distinguishing between control variables and mediators is inconsistent across studies, however. Although many studies control for social support, there are few studies that formally test the potential mediating role of social supports and coping mechanisms in order to disentangle the specific direct and indirect effects of religion. Therefore, most studies are inconclusive about whether the effects of religiosity directly affect health outcomes or operate indirectly through other factors such as social supports or greater self-esteem.
Notably, several studies control for variables that are associated with mental and physical health outcomes including functional limitations, disease stage, treatment, and potential sources of stress ranging from domestic abuse to perceived racism. Not all studies include a comprehensive or a consistent set of control variables, which complicates comparison of the effects across studies.