Clear cache and session variables

If I write code on the home page of a website to clear the users cache whenver they navigate to it, will it clear any session variables that where set within the site? What I want to do is make sure the users cache is cleared when they first get to the site. Within the site, there are different places t  login in which session variables are set for the user. If this is done and the user then navigates back to the home page, will their session variables be lost? If so,can anyone suggest a good work around for this.

Thanks