Anyone signed into QuizUp can view the stats on someone's public profile. If you'd like to make sure that only approved followers can see your stats and profile we suggest making your profile private. Once you set your profile to private, anyone who wants to see your profile will have to send you a follower request which you can then approve or ignore.
You can also remove followers and block other people on QuizUp. When you block another user, that user can't view your profile or search for your QuizUp account. Users aren't notified when they're blocked. Learn more about blocking users.