When I first joined LinkedIn, it suggested all kinds of obscure connections to me, like the real estate agent I'd used two years previously, and the wife of my landlord... I had definitely not given LinkedIn my contacts, and in any event, I didn't even have my landlords wife in them. I'm assuming my info must have been inferred from info those contacts or their network had about me.
So in any case, LinkedIn is super creepy with way (and I thought I'd read they lost a lawsuit about contact mining) but the information leak may not be anything you did, but rather information that was inferred from the doctor somehow, your partner, or some higher order connection.
Great example of poor algorithmic governance.