Figure 6.

Frequency and distribution of the study participants by earliest calendar year lived in study area and residency duration. Colored squares indicate the number of participants with various combinations of earliest calendar year and residency duration. The earliest year is either 1947 for participants living in the study area at the start of the residential history, or the year participants moved to the study area. Residency duration is calculated as the difference between earliest year and diagnosis year for cases or index year for controls.