Does the development of dementia have anything to do with sleep problems such as insomnia?

We have been learning about sleep in psychology and I now know (though I did know this just not to the same extent) that in our sleep our brain sorts through our memories and what we have learned in that past day. If we don't get enough sleep over a long period of time for example being a long term sufferer of insomnia can that affect memory and other cognitive functions later on in life and cause say dementa?