It looks like Fitbit won't be sharing data with the new iOS 8 Health app anytime soon. Responding to a question in support forums, a representative for the company said that it "currently has no plans to integrate with HealthKit."
The rep adds that HealthKit is an interesting new platform that Fitbit will be watching as it matures, as it looks for opportunities to improve the user experience. "But at the moment," he says, it's working on "other exciting projects."