The Gulf Long-Term Follow-Up Study will survey Gulf of Mexico residents who helped with the cleanup of last year's Deepwater Horizon oil spill and follow them for at least 5 years.

The diagnosis of the cases in the database has been confirmed, either by biopsy or by long-term follow-up, so there is no doubt about their details.

Cardiologists have had to decide which type of stent to use in heart attack patients based on small randomized trials that didn't include long-term follow-up and reported conflicting results.