Your friend is on Instagram notification

I have installed Instagram and now it notifies me: > Your friend bob is on Instagram as bob123. I don't remember giving it permissions to access my contacts and when I go to Android Settings > Applications > Instagram it does not have any permissions enabled. How does it know my contacts and how can I disable it? Note: I do not have Facebook connected. In fact it has a banner across the top of the app asking if I want to connect Facebook