Previous studies of regional and temporal variation in U.S. breast cancer mortality rates have been confined largely to analyses of rates for white women.
Breast cancer mortality rates from 1969 through 1992 for white women and black women in four regions of the United States and for all women throughout Canada were compared to identify racial, regional, and temporal differences. Differences and trends in the rates were evaluated in view of breast cancer risk factors and relevant medical interventions.
Age-period-cohort models were fit to the data, and changes in birth cohort trends (suggesting a change in a breast cancer risk factor or protective factor) and calendar period trends (suggesting, in part, the impact of new or improved medical interventions) were examined.
Breast cancer mortality rates for white women were significantly higher in the Northeast than in any other region of the United States (two-sided t tests; P