Does Twitter track your IP address?

[Kurt]

I have 2 Twitter accounts. One is my personal account and another I use for anonymously to interact with people who share my disability. However, I have noticed that on my private account myself and people I know are appearing as suggested friends.

I use 2 completely different emails and the accounts are not linked in any way at all.

This is a worry for me as I have not disclosed my disability and due to prejudices surrounding mental illness I am very worried how I would be viewed by work colleagues, etc if I was found out.

I have been very careful to keep my accounts separate, always sign out and clear my history after each log in. Is Twitter tracking my IP address or is something else going on that is linking the accounts?
If they don't track your IP address - how are they linking the accounts?