Transient ischemic attacks are caused by thrombi that stick in some brain arteries and cause temporary stop of the blood flow. Blood has its own mechanisms (fibrinolytic system) for dissolving the sticked thrombus. Thrombi are usually created on some atherosclerotic plague placed in the carotid arteries. Irregular heart rhythm can also cause creation of thrombi in the left heart chamber that flows up to the brain.
Type of work do not have influence on thrombi creation.
Do you have some heart arrhytmia?
Have you ever made carotid arteriography or carotid doppler examination?