Increased excess deaths in urban areas: quantification of geographical variation in mortality in Japan, 1973-1998

To quantify the magnitude of geographical health inequality by sex and age group, and to observe the change in regional distribution of health disadvantage, this study estimated excess deaths attributable to the mortality variation among municipalities across Japan from 1973 through 1998. The municipalities (N = 3340 in 1995) were divided into quintiles according to standardized mortality ratio (SMR). Using the mortality of the lowest SMR quintile as the standard, the number of excess deaths (ED) and its ratio to observed deaths (EDR) were estimated by sex, age group (total population and under 65-year population) and regional block in 1973-1977, 1978-1982, 1983-1987, 1988-1992 and 1993-1998. Total annual ED in 1993-1998 was estimated as 47,124 for males and 46,562 for females, representing EDR of 9.9 and 11.6%, respectively. The under 65-year population had a higher EDR than the total population. Rural regions showed a marked decrease in EDR in contrast to the increase in urban regions over time. The present study suggests that the reduction of a large number of deaths, especially premature deaths, is expected by elimination of geographical health inequality, and that health policies for urban residents are prioritized.