What Causes Lack Of Smell And Taste Sensation After Gastric Bypass Surgery?

2 months ago i had gastric bypass as suffer from type 2 diab and sleep apnea. just had blood tests and it seems my diabetes is on its way out but now have an underactive thyroid, have started on tablets. but want i want to ask is could these conditions be responsible for my total lack of smell {2 years now} and recent lack of taste. the only time i could smell recently was the day after the operation.