Interrelation between Western type cancers and non-Western type cancers as regards their risk variations in time and space. I. Mathematical linkage among multiple cancer incidences.
The present study attempted to clarify the interrelation between multiple cancer risks by comparatively investigating the age-adjusted incidence rates (AAIR) of 8 neoplasias in 20 selected populations of the world for the last 20 years. Cancers of the stomach (for both sexes) and uterine cervix were on the decline in their incidences, and cancers of the colon (for both sexes), lung (for both sexes), breast and endometrium were on the rise in the period 1960 to 1980. Cancers of the esophagus (for both sexes) and ovary exhibited little change in their incidences during this period. A negative linear relationship was detected between the log-transformed AAIR of an increasing (Western type) cancer and that of a decreasing (non-Western type) cancer, and a positive linear relationship was detected between 2 increasing or 2 decreasing cancers regarding the log-transformed AAIR. Mathematical evidence is presented to indicate that the sum of AAIRs of both increasing and decreasing cancers can be minimized within the frame of a competitive relationship. The results obtained are discussed from the view point of cancer etiology.
Kodama
M
M
Kodama Research Institute of Preventive Medicine, Nagoya, Japan.
Murakami
M
M
Kodama
T
T
D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D008433:Mathematics; D015233:Models, Statistical; D009369:Neoplasms / Q000453:epidemiology* / Q000209:etiology / Q000517:prevention & control; D012044:Regression Analysis; D012306:Risk; D013997:Time Factors