Back to home pageJANUARY 1993 - NUMERO 205
93.32.05 - English - Shigesato TAKAHASHI
Future Life Expectancy and Causes of Death in Japan (p. 1-15)
In 1990, 12.5% of the Japanese population was aged 65 years and over. The Institute for the Study of Population Problems forecasts that this proportion will increase to 17% by the year 2000 and to 25.8% in 2025. This ageing of the population will result in an increase in the number of deaths: from 820,000 in 1990, it is foreseen that they will reach 1,026,000 by the year 2000 and 1,694,000 in 2025. In this article, the author estimates future levels of life expectancy, using a life table projection model with a modified cause-, age- and sex-specific mortality structure: male life expectancy increases from 75.5 years in 1990 to 79.5 in 2025, while female life expectancy increases from 81 to 86.5 years. Much of the increase in life expectancy can be attributed to the decline in mortality from cerebro- and cardiovascular disease. From 1990 to 1995, the drop in rates of mortality from cerebrovascular disease is responsible for 38.3% of the increased life expectancy for men and for 22.6% in women's. From 2020 to 2025, 20.7% of male mortality and 22.0% of female mortality will be due to cerebrovascular disease, and cardiac disease for 30.4% and 32.6% respectively. Furthermore, the author studies the effect of several scenarios of trends in various aspects of mortality from 1990 to 2025 on the proportion of elderly, the number of deaths, life expectancy and the structure of cause-specific deaths. It is indeed the decline in mortality which will be the major factor in the increased proportion of the elderly in the population. (JAPAN, LIFE EXPECTANCY AT BIRTH, CAUSES OF DEATH, FORECASTS, CEREBROVASCULAR DISEASES, CARDIO-VASCULAR DISEASES)
APRIL 1993 - NUMBER 206
93.32.06 - Japanese - Shigemi KONO, Reitaku University, 2-1-1, Hikarigaoka, Kashiwa-shi, Chiba-ken 277 (Japan)
Population and Women: A Study of Sex Ratios in Population and Gender Differentials in Demographic and Social Participation (p. 1-16)
The author studies the relative proportion of males and females in various demographic and social phenomena such as birth by order, unmarried population in various age groups, etc. Some of the results show that there still exist discriminatory practices against women with regard to access to given areas of economic and social life and the benefits of social life, such as comfort and health. Furthermore, in numerous cases, cultural customs only exacerbate the effects of the numerical differences between males and females, in particular with regard to marriage and remarriage. It is towards the end of their lifespan that women seem to accumulate all the disadvantages of their high level of numerical superiority: widowhood, solitude, lack of care, loss of economic security, poverty. Population ageing will only serve to intensity this problem in the next century. (WOMEN'S STATUS, SEX RATIO, SEX DISCRIMINATION)
93.32.07 - Japanese - Ryuichi KANEKO
A Projection System for Future Age-Specific Fertility Rates (p. 17-38)
A new system for projecting fertility was used to calculate Japan and its prefectures' official population projections in September and November 1992. The calculation is based on an age- and parity-specific fertility model and transforms the behavioural parameters of generations into future age-specific fertility rates. In the early stages, the author tested various nuptiality models with regard to their aptitude for correctly predicting the fertility characteristics of generations. It is the 4-parameter log-gamma distribution model which appeared the best from this point of view and which was therefore used for projecting age- and parity-specific fertility rates up to the year 2025. These fertility rates are projected amongst the generations and then, transformed into. The comparison between actual rates and the forecasted rates calculated by the model, in the years where this is possible, is good. The author briefly mentions some of the technical aspects of using this model. (JAPAN, MODEL, PROJECTIONS, FERTILITY RATE, AGE-SPECIFIC RATE, PARITY PROGRESSION RATIO)
JULY 1993 - NUMBER 207
93.32.08 - Japanese - Toru SUZUKI
The Sisters' Riddle in Age-Parity-Structured Stable Population (p. 1-13)
N. Goldman (1978) showed that, in a growing population, the probability for ego of having a younger sister is greater than that of having an older sister: the relationship is the opposite for a declining population. She therefore deduced a method for estimating the population growth rate based on the relationship between the number of younger sisters and the number of older sisters. But K. Wachter (1980) indicated that the probability of having a younger sister has to be the same as that of having an older sister and he then introduced as the "Sisters' Riddle" the fact that this link varies with the rate of growth instead of remaining equal to 1. The author introduces into this reasoning the age structure and birth order of the stable population. This allows him to make some refinements to the mathematical formulation of the problem and to throw some light on both facets of the riddle. The relationship between the proportion of younger sisters to older sisters and the population growth rate depends on the parity structure of fertility. (MODELS, STABLE POPULATION, POPULATION GROWTH, SISTER)
93.32.09 - Japanese - Hiroshi KOJIMA
The Concepts of Integration Regarding Immigrants (p. 14-32)
The various official definitions of immigrant integration in current use in developed countries are compared in this article. First of all, it is the definition of the concept of an immigrant which changes from country to country, depending on whether the criteria chosen are psychological and socio-economic (France, Belgium, Netherlands) or statistical and legal (Sweden and United Nations). Quantitative estimates are usually supplied by the demographic statistics which distinguish between the place of birth, language and nationality (both at birth and acquired). With regard to the concept of integration, it usually makes use of on or several of the following elements: becoming a fully-fledged member of the host society, maintaining the cultural differences, accepting reciprocal influences. But the definitions vary according to the country, the institutions in one and the same country, or even from one document to another within one organisation. The difference between the individual and aggregate approaches to the phenomenon partly explain this variability, but the term "integration" remains ambiguous. From this comparative study, the author draws two lessons for Japanese policy on immigrants: the necessity of collecting and analysing statistical data where the nationality and place of birth are known and the necessity of developing research in the governmental organisations implicated in the preparation of future integration policies. (JAPAN, INTEGRATION, IMMIGRANTS)
93.32.10 - Japanese - Tamotsu OHBA
Evaluation of the Characteristics of Simulation Model for Migrations and Dispersals of Prehistoric Human Populations (p. 33-52)
The author continues herewith the presentation of his migration and spatial distribution model for prehistoric populations. It is a computerised simulation of an experimental hexagonal space of 1,261 hexagonal cells. An "initial population" of one hundred individuals is installed in the centre of the space and, by combining six parameters, the model calculates the time required by the population to reach the peripheral cells and the total population from one period to another. The parameters and the conditions in which they are applied deal with the individual probabilities of migrating from one cell to another depending on the population situation of each cell. Several scenarios are tested, leading to types of more or less wide and rapid population dispersion. The author finally studies the possibility of using this model in order to examine the migration patterns of modern populations. (MATHEMATICAL MODELS, SIMULATION, MIGRATION, SCATTER OF THE POPULATION, PALEODEMOGRAPHY)
1993 - NUMBER 208
93.32.11 - Japanese - Makoto ATOH, Shigesato TAKAHASHI, Eiko NAKANO, Yoshikazu WATANABE, Hiroshi KOJIMA and Ryuichi KANEKO
Trends in Marriage and Fertility in Japan: Major Findings from the Tenth Japanese National Fertility Survey (p. 1-28)
The Tenth Japanese National Fertility Survey was carried out by the Institute for the Study of Population Problems (Ministry of Health and Social Welfare) on July 16th, 1993. The observation units were currently married women aged under 50 and the method used was one-degree cluster sampling. Out of the 800,000 districts in the survey, 490 were systematically chosen and the sample built up in this way contained 10,878 married women of whom 9,908 (91.1%) gave satisfactory responses. The authors provide the main results of this survey, as follows: an increase in the average age at marriage, a trend towards generalisation of "love matches" and a drop in arranged marriages, a correlated prolongation of time spent getting to know each other before marriage; and a marital fertility of slightly over two children. Over 80% of married women have two or three children during the first five years of marriage. It is very rare to find a family without children or with only one child. The survey also makes it possible to study differential fertility by age at marriage, socio-economic category and place of residence. 60% of young couples wish to have two children while 30% want three. Many consider a family of three children to be ideal, but intend to have only two. Finally, preferences for children of a given sex have changed dramatically over a ten-year period: amongst those women who only want one child, 76% prefer this to be a girl. (JAPAN, FERTILITY SURVEYS, AGE AT MARRIAGE, LEGITIMATE FERTILITY RATE, DESIRED FAMILY SIZE)
93.32.12 - Japanese - Hiroshi KOJIMA
A Policy-oriented Analysis of Fertility Behaviors and Attitudes in Japan (p. 29-50)
The present study attempts to evaluate the effects and potential objectives of possible pronatalist family policies in Japan. The author applies the proportional risk and binomial log models to the data of the Eighth National Fertility Survey (covering more than 8,000 women) which was undertaken in 1982 by the Institute of Population Problems. The dependant variable is the probability of a third birth (and the corresponding interval) since this is often the objective of pronatalist family policies and since most Japanese couples do already have at least two children. The gap between the ideal number of children and the envisaged number of children is also emphasised as the couples for whom the former is higher than the latter are supposed to require political measures which would help them to achieve their goal and because the government can justify an intervention aimed at these couples. The income of a couple, the wife's employment and accommodation have been chosen as independent variables linked to the policy, after controlling for the marriage generation, the wife's age at first marriage, the means of choosing the spouse, the young household's residence, the wife's level of education, the husband's occupation, the place of residence and the region. The study results lead to believe that increased financial aid for couples belonging to the average-to-high income sector could result in pronatalist effects and that the same could be said for measures which would help working women (and their husbands) to run their working lives and family lives simultaneously, and measures which would improve public sector accommodation possibilities and/or offer a housing grant or a tax rebate on rents (if a reduction in inheritance and donation taxes were not to prove practicable, for other reasons). (JAPAN, PARITY PROGRESSION RATIO, PRONATALIST POLICY, INCOMES POLICY, HOUSING POLICY, FEMALE EMPLOYMENT)
93.32.13 - Japanese - Yoko IMAIZUMI
Perinatal Mortality Rates in Single and Multiple Births, and the Effects of Maternal Age, Birthweight, and the Other Factors on the Perinatal Mortality Rates in Japan (p. 51-65)
Based on Japanese civil registration statistics for the period 1950-1991, the author studies trends in perinatal mortality rates according to sex and for single and multiple births. The effects of the mother's age, birth order, length of gestation and birth weight on perinatal mortality rates are also examined. The results thus obtained lead to the conclusion that the perinatal mortality rate has declined considerably from year to year. It is higher for males, but the gap between males and females has declined over time. Compared to single births, the perinatal mortality rate is six to seven times higher for twins, 12 to 13 times higher for triplets, 15 to 22 times higher for quadruplets and 50 to 87 times higher for quintuplets (for the period 1980-1991). Amongst twins and triplets (but not quadruplets), the perinatal mortality rate increases with the children's birth order. From the second birth onwards, the rate increases with the birth order (for the period 1968-1991). As for birth weight, the rate is at its lowest when the child weighs between 3.0 and 3.4 kgs for a single birth, or from 2.5 to 2.9 kgs for a multiple birth (for the period 1979-1991). At less than 2.5 kgs, children from multiple births are the least vulnerable while the opposite is true at weights over 2.5 kgs. With the exception of the shortest durations of pregnancy, birth weight is more important than pregnancy duration for the perinatal mortality rate. (JAPAN, PERINATAL MORTALITY, MULTIPLE BIRTHS, MATERNAL AGE, BIRTH WEIGHT, BIRTH ORDER, DURATION OF PREGNANCY)
Back to home page