An official website of the United States government
Here's how you know
Official websites use .gov
A
.gov website belongs to an official
government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you've safely
connected to the .gov website. Share sensitive
information only on official, secure websites.
Headache incidence was recorded in a daily diary. The mean number of days that headache was experienced per week during the respective study phase is presented (±95% CI). Headache incidence decreased over the course of the study (P<0.001). * denotes P< 0.01 compared to Baseline.