Does anyone know the odds of a husband and wife both developing AD? My grandfather-in-law was diagnosed about 2 years ago. Now his wife, my grandmother-in-law, has also been diagnosed. He is in his 75 and she is 69. Some of the family has started to wonder if there might be an environmental factor to them both developing AD. He was in the U.S. Army and retired from a car manufacturing plant. She was a homemaker. Does anyone know of any environmental factors that could have affected both of them? Thank you for your time!