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.
Rate ratio of breast cancer in Canada by birth cohort. Cohorts from 1888 to 1988, with 1936 as the reference cohort. Shaded area represents 95% confidence intervals