The international mortality pattern for 15 sites of malignant neoplasm using factor analysis

抄録

Many geographical studies relating to malignant neoplasm were carried out in the '70s. The mechanism of gene mutation with respect to malignant neoplasm has been clarified since the '90s. Understanding the geographical distribution of the mortality pattern may be helpful for the exploration of unknown factors concerning the onset of malignant neoplasms, since geographical factors are thought to influence gene mutation. To seek clues for the potential existence of these unknown factors, I examined the relationship between site-specific mortality from malignant neoplasms and geographical distribution for 46 countries. In addition, I tried to understand the characteristics of the Japanese mortality pattern in comparison to other countries. The numbers of deaths categorized by cause, sex and age, and the numbers of populations were obtained from the World Health Organization (WHO) database. Factor analysis was employed for age-adjusted death rates to explore latent factors. Three factors were extracted for each sex. Males' Factor 1, characterized by leukaemia and neoplasms of the lung, colon, bladder, oral cavity, rectum and oesophagus, indicated a pattern similar to females' Factor 2. Eastern European countries may be mainly influenced by males' Factor 1. Females' Factor 1, characterized by neoplasms of the cervix uteri, liver, uterus and stomach, indicated a pattern that is comparatively similar to males' Factor 3. Central and southern American countries and Eastern Europe may be mainly influenced by females' Factor 1. The characteristics of the Japanese mortality pattern could be seen as intermediate between those for Westernized developed areas and less developed areas.