What Causes Imbalance In Body And Slurred Speech?

I am a 70 year old male and have never had a major health issue other than iron overload. I take no prescription drugs. During the last year I have noticed problems with my balance. I don t seem able to walk in a straight line without weaving to some degree. I can t stand on one leg for more that a few seconds. Recently I notice I am not enunciating my words as well as I used to and at times my speech sounds a little slurred (I m used to public speaking). I don t drink alcohol. Any ideas?