A geographic analysis of prostate cancer mortality in the United States, 1970–89

The recently published atlas of cancer mortality in the United States revealed that prostate cancer mortality rates were elevated among white men in the Northwest, the Rocky Mountain states, the north-central area, New England and the South Atlantic area, and among black men in the South Atlantic area. Here we determine whether the elevated regional rates were statistically different from rates in the rest of the country and whether the pattern can be explained by selected regional characteristics. A spatial scan statistic was applied to county-based mortality data from 1970 through 1989 to identify geographic clusters of the elevated rates for prostate cancer. Five clusters of elevated mortality were detected in white men (p < 0.005) and 3 in black men (p = 0.0001-0.056). For white men, the primary cluster was in the northwestern quadrant, followed by clusters in New England, the eastern part of the north-central area, the mid-Atlantic states and the South Atlantic area, whereas for black men the primary cluster was in the South Atlantic area, followed by clusters in Alabama and the eastern part of the north-central area. Further analyses of these clusters revealed several significant subclusters (p < 0.05). None of the selected demographic and socioeconomic factors, separately or collectively, accounted for the primary clusters in the U.S. white and black populations. The patterns observed could not be attributed to selected demographic or socioeconomic characteristics but should provide leads for further study into the risk factors and the medical or reporting practices that may contribute to geographic variation in mortality from prostate cancer.