Port Status via Meraki Dashboard API

I am currently playing around with the Dashboard API and I am wondering if there is no way to pull out the Port status "Up" or "Down" via API from the dashboard.

I got several information about switch ports, but not the connection state? Is this true?

Yes! 

You want to look at the clients API, which is time based let's you see all of the client devices connected to the switchports over the the last month down to just the last second.

Clients API

For uplink status you want to look at this API:

WAN Uplink Status

If you see no clients on a port, you know it's not in use, but it could also just be disabled. That requires checking to make sure the port is not disabled. It sounds like you already looked at the Switchports API:

SwitcSwitch Portshports