Exploring causes for declining prostate cancer mortality rates in the United States

Prostate cancer mortality rates in the U.S.A. increased in the late 1980s and declined from 1993 until 2003. The purpose of this study is to compare declining prostate cancer mortality rates among states with independent variables that may have an association to explore causes for the decline.

Annual rates of prostate cancer mortality for men over 50 were obtained from the National Vital Statistic System public use data file for states for individual years from 1993 to 2003. The annual rate of prostate cancer mortality decline for each state was calculated by the Joinpoint Regression Program (Statistical Research and Applications Branch of NCI). Annual rates of prostate cancer decline were cross-correlated to state levels of PSA screening, health insurance coverage, obesity, physical inactivity, diabetes, and high cholesterol for males from 45 to 64.

Declining prostate cancer mortality rates for white males correlated with high cholesterol levels (R = -0.42, P = 0.002) and PSA screening levels (R = -0.28, P = 0.05). Declining prostate cancer mortality rates for black males correlated with health insurance coverage (R = -0.43, P = 0.03).

Declining prostate cancer mortality rates are weakly associated with increased PSA screening for white males but there was no association for black males, possibly because blacks have less access to medical care. The strong inverse correlation between declining prostate cancer mortality rates and levels of white males with high cholesterol levels was unexpected but may be associated with the widespread use of cholesterol reducing medications (statins), which are hypothesized to reduce prostate cancer risk.