Show one task at a time, using progressive disclosure
On your first screen, you can provide a simple checkbox questionnaire where the user can identify any health issues that they may have.
When the user clicks Continue, you'll ask for more information on each identified condition. Use a different screen for each condition, and only show screens if the user has identified having them. For example:
Is your diabetes treated with insulin? Yes/No
[If the user clicks Yes]
What is your insulin type and dosage? ___
This allows the user to concentrate on each health condition without feeling overwhelmed by everything else on the page.