Analysis of sex, age and disease factors contributing to prolonged life expectancy at birth, in cases of malignant neoplasms in Japan.
BACKGROUND
This study aimed to examine the contribution made by the change in mortality from malignant neoplasms to the life expectancy at birth, observed during the years 1965-1995 in Japan.


METHODS
We used data on the population and number of deaths by cause, age and sex in 1965, 1975, 1985 and 1995. The contribution of different ages and causes of death to the change in life expectancy were examined with the method developed by Pollard.


RESULTS
We found that, among all causes, the decrease of mortality from stomach cancer led to the greatest improvement in life expectancy for both sexes. On the other hand, negative contributions were seen with cancers of many sites, such as cancer of the intestine, liver and lung for males, and cancer of the intestine, gallbladder, lung and breast for females. Recently, the contributing years of all cancers have been negative because of the increase in mortality from malignant neoplasms. In addition, increase of death from malignant neoplasms in middle-aged and elderly people negatively influenced the life expectancy at birth.


CONCLUSIONS
Female cancer influenced the improvement in life expectancy at birth. Cancer for males, however, contributed little to improvement of life expectancy at birth except for a little prolongation of life expectancy at birth during the years 1965-1975. To develop a public health policy, the contributing years to life expectancy at birth can be a useful indication in evaluating the impact of death from various diseases. It is necessary to analyze the contribution made by various causes of death to the changes of life expectancy at birth.
Graduate School of Medicine, Nagoya University, Japan.
Tomoyuki
T
Watanabe
Masako
M
Omori
Hiromi
H
Fukuda
Hiroki
H
Takada
Masaru
M
Miyao
Yutaka
Y
Mizuno
Isao
I
Ohsawa
Yuzo
Y
Sato
Toshihiko
T
Hasegawa
D000293:Adolescent; D000328:Adult; D017677:Age Distribution; D000367:Age Factors; D000368:Aged; D001943:Breast Neoplasms / Q000401:mortality; D002423:Cause of Death; D002648:Child; D002675:Child, Preschool; D004067:Digestive System Neoplasms / Q000401:mortality; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007564:Japan / Q000453:epidemiology; D008017:Life Expectancy / Q000639:trends*; D008297:Male; D008875:Middle Aged; D009369:Neoplasms / Q000145:classification / Q000401:mortality*; D012142:Respiratory Tract Neoplasms / Q000401:mortality; D017678:Sex Distribution; D012737:Sex Factors; D016019:Survival Analysis; D014565:Urogenital Neoplasms / Q000401:mortality