Does Long Term Use Of Nexium, Valium And Lexapro Cause Dementia?

Is it possible that certain medicines taken over long number of years can increase the risk of early dementia I suffer from IBS and also chronic back pain , I am on long term 20/40 MG per day of Nexium 120mg per day of Spasmanol . I also tak 5/10 Mg of Lexapro and 4Mg of Valium each night I would very much appreciate your opinion Regards John