都道府県別平均寿命の過去30年間の経年変化とその特性 : 東京都を中心として

都道府県別にみた平均寿命の30年間の経年変化の実態を分析し、特に東京都平均寿命の特性を明らかにすることを目的とし、1965年から1995年までの5年毎30年間の男女別都道府県別平均寿命を分析対象として調査を実施した。都道府県別平均寿命の経年変化をみると、男女共に急速に延びていった。しかしながら性別にみた増加傾向は同一ではなかった。女性の平均寿命は、1985年頃まで直線的に延長していったが、1990年以降はその延びが鈍化し上に凸な二次曲線の延びとなっていった。男性の増加傾向は、女性よりも5年早く二次曲線の延びに変化していた。都道府県別平均寿命の地域間格差を経年的にみると、1965年では男性で最大4.52歳、女性では同様に3.46歳であったものが、30年後の1995年では、男性で3.67歳、女性では3.25歳へと縮小していった。1965年の時点で、最も短い平均寿命は、男性では青森県の65.32歳、秋田県の65.39歳で、女性では秋田県の71.24歳、岩手県の71.58歳であった。一方、最も長い平均寿命の地域は、男性で東京都の69.84歳、京都府の69.18歳、女性では東京都の74.70歳、神奈川県の74.08歳であった。1965年の時点において、東京都の男女の平均寿命は突出して高い値を示していたが、年次経過とともにその延びは鈍る傾向を示し、30年後の1995年における順位は大きく変化していった。30年後の1995年の東京都平均寿命の男性順位は20位で、女性平均寿命の順位は35位となり、他の道府県の平均寿命の延びに比べて、延び率が少ないことが明らかになった。

The life expectancy of the average Japanese has increased rapidly compared with life expectancies of populations in other developed countries. The rates of increase, however, are not the same in a1147 prefectures throughout Japan. In order to better understand the distribution and trends of life expectancy of both sexes of the 47 prefectures, descriptive analyses were made based on life expectancy at birth. The main purpose of this study was to clarify the differences in life expectancy between prefectures and uncover factors responsible for the deceleration in increase rate, which was very high in the 1970s to the early 1980s, observed from late 1980s to 1990s. Data obtained from the Ministry of Healthy and Welfare, showing changes in life expectancy at birth at five-year intervals during a period of 30 years, were analyzed. The findings were as follows: 1) A great difference among 47 prefectures in life expectancy at birth existed. Figures of 1965 indicated that life expectancy at birth was shorter in northern prefectures than in southern prefectures. 2) The gap between the prefectures having the longest and the shortest life expectancy at birth was 4.5 years for males and 3.5 years for females. 3) Between 1965 and 1995, life expectancy at birth in Akita Prefecture increased the most among the 47 prefectures. A similar increase was observed in rural prefectures rather than in urban ones. 4) In 1965, life expectancy at birth for both sexes in Tokyo was the highest with 69.84 years for males and 74.70 years for females. This is due to the extremely low mortality rate among young people. 5) Life expectancy at birth for Tokyo increased by 4.62 years for males and 4.79 years for females between 1965 and 1980. The rate of increase decelerated considerably between 1980 and 1995; the increase during this latter period being only 2.45 years and 3.63 years, respectively. 6) Projections indicate that the trend of higher increase in rural prefectures than in urban prefectures will continue. As a consequence, the gap among prefectures is likely to widen. 7) In 1995 newborn girls could expect to live 6.2 years longer than newborn boys. This gap was 6.8 years in 1975 and 7.0 years in 1965. The female-male gap is widening among older people. 8) The trend in life expectancy at birth in Tokyo over the past 30-year-period is an important study theme for public hea1th policies. 9) These findings have important consequences for prioritizing public hea1th policies. More sophisticated epidemiological research projects are important for the formulation of public hea1th strategies in Tokyo. 10) The review of the findings suggests that it is very important to clarify not only the descriptive health status but also the relationship between the main controllable factors and discrepancies of life expectancy among the 47 prefectures.