Usage patterns
〈物〉と〈物〉の結びつきがあるthere is a connection between A and B
There is a connection between diet and health.
結びつきが強いthe bond/connection is strong
The connection between the two companies is strong.
結びつきを深めるto deepen a connection/bond
They deepened the bond between the two countries through exchange.
結びつきを持つto have a connection (with something)
He had a connection with that incident.