Engagement API Associated to Contact Email


Hi - have been looking at using engagement API to create note/email associated with a contact but can only see associations based on contact_id - is it possible to associate based on contact_email address in anyway? Using the API to get the contact_id with the email using http://developers.hubspot.com/docs/methods/contacts/get_contact_by_email seems an unnecessary step if emails are uid’s in hubspot anyway.

Thank you all