LONGITUDINAL GOMPERTZIAN ANALYSIS OF STOMACH-CANCER MORTALITY IN THE UNITED-STATES 1962-1987 - A THERMODYNAMIC ANALOGY OF ITS DECLINING MORTALITY

Age-adjusted mortality rates for stomach cancer (SC) in the United States from 1962 to 1987 were subjected to longitudinal Gompertzian analysis. Age-adjusted SC mortality rate distributions between age 50 and 85 years were highly Gompertzian for each and every year for both men and women. The environmental 'temperature' or intensity factor declined (improved) 1.55-fold for men and 2.04-fold for women in 1987 as compared to 1962. If the environmental 'pressure' or frequency factor had remained constant, the age at the theoretical common intersect point would have been 56.0 years for men and 80.0 years for women and overall SC mortality would have increased. However, between 1962 and 1987, non-age-standardized annual crude SC mortality rates decreased 46.8% for men and 44.0% for women. The thermodynamic analogy for this apparent discrepancy is that the environmental 'pressure' factor has not remained constant, but rather declined 51.7% for men and 60.9% for women between 1962 and 1987. This suggests that the overall frequency of environmental challenges that contribute to SC mortality has become significantly reduced.