[Male life expectancy and prolongation of life expectancy were lowest in small towns in Japan].

The relationship between size of population and life expectancy of residents was investigated in 652 cities in Japan, using municipal life tables for 1985 and 1990. The following findings were seen: 1) Population size and life expectancy Life expectancy of males at age 0, 20 and 40 was lowest in small towns with a population less than 30,000 (except for age 40 in 1985), and highest in cities with a population of 70,000-199,999 in 1985 and 1990. Life expectancy of females at age 0, 20, 40 and 65 did not significantly vary with size of population in 1985 and 1990. 2) Population size and prolongation of life expectancy (1985-1990) Life expectancy was prolonged in males by 1.02, 0.88, 0.86 and 0.66 years at age 0, 20, 40 and 65, respectively. The prolongation of life expectancy of males at age 0, 20 and 40 was smallest in small towns with a population less than 30,000. Life expectancy was prolonged in females by 1.41, 1.32, 1.29 and 1.12 years at age 0, 20, 40 and 65, respectively. The prolongation of life expectancy was shortest at birth for females who lived in cities with a population of 50,000-59,999. 3) Socioeconomic factors and prolongation of life expectancy The prolongation of life expectancy of males was related to the entrance rate for high school and inversely related to the unemployment rate. The prolongation of life expectancy of females was not related to any of the socioeconomic factors studied.