Researchers conducted a case control study on whether sex (male vs. female) is associated with the disease (Malaria). But they also wonder working environment (outdoor or indoor) may play a role in the association. The information is given as followed:

Total 300 patients participated this study including 150 cases and 150 controls, respectively. Out of 150 patients with malaria, 88 of them were males compared 68 out of 150 controls.

Of males, 53 cases and 15 controls had outdoor occupation; Of females, 10 cases and 3 controls had outdoor occupation.

Use the information above to show and discuss whether working environment in this study is a confounding or interaction variable