CHICAGO - Just days after announcing a crackdown on researchers who do not disclose drug company ties, the editor of a prestigious medical journal says she was misled again -- this time by the authors of a study linking severe migraines to heart attacks in women.

All six of the study's authors have done consulting work or received research funding from makers of treatments for migraines or heart-related problems. Their research appears in Wednesday's Journal of the American Medical Association, a week after the crackdown was announced.

The authors said they did not report their financial ties because they did not believe they were relevant to the study.