They most certainly could be related. If you had a few background apps doing something, such as playing music while browsing the web, that would take more clock cycles. Even something like a native twitter app running in the background could be pinging twitter several times a minute, obviously requiring power to do so.
Every iPhone and iPod Touch ever released has had background apps running at all times to provide services like e-mail. How do you think the iPod mode on an iPhone works? It plays music while you're browsing in Safari by leaving an app running in the background. Email notifications? App running in the background.
