.... my husband of 40 yrs, he will be 70 soon; his bedroom has similar odour...sort of greasy and I change his pillow case every day or two... he has frequent showers; smoker since age of 15 and where his back has been on the sheet over time there is a light brown stain.... his clothing is clean , he uses deodorant...he has never asked a dr. about this as seems oblivious to it. Even after I launder the bedding there is a slight odour especially on the pillow slip..I used to work with a woman who said her husband's same and she put it down to his diabetes, not sure why, but my husband has it too... maybe some other readers have some suggestions ..... J.