Perinatal mortality rates and proportion of deliveries by birth weight, maternal age, birth order, single or multiple birth, sex, place of delivery, and delivery attendant, were compared between Gifu Prefecture, and Japan as a whole in 1974. The results were as follows: 1. The perinatal mortality rates in Gifu Prefecture were higher than those of Japan as a whole. 2. The difference between perinatal mortality in Gifu Prefecture, and those in Japan, was related to the proportion of low, birth-weight deliveries.
The fishing activity with self-contained underwater breathing apparatus (shortly SAC U B A) diving method and the fishermen's health condition were investigated. Data were obtained by field survey on diving fishermen on two fishing communities in Okinawa in June and July, 1979. Another data were based upon the clinical records of decompression sickness, usually called divers' disease, patients who attended the Hospital, College of Health Sciences, University of the Ryukyus for the hyperbaric therapy from July, 1973up to August, 1979. Results are summarized as follows:(1) Divers' disease patients have increased rapidly among SCUBA diving fishermen in these few years.(2) As to the cases of the patients, the "Bends"-typed sickness, the comparatively slight one, occupies the highest ratio (59.6%).(3) The failure in the "decompression" method for the therapy, which has been almost done among the diving fishermen, makes sometimes them more serious sickness.(4) SCUBA diving fishermen force themselves considerably to be engaged in the diving activity as compared with the standard diving method not to be suffered from the divers' disease.(5) Their forcible diving activity is connected with their competition for a good catch, which seems to be leading to the exhaustion of marine resources.(6) The frequent occurrence of the diving fishermen's decompression sickness is closely related to the cultural factor of traditional fishing method, ecological factor of marine resources, and social factor of social structure such as co-operative systems of Okinawan fishermen.
Effects of out-migration upon households composition are not necessarily fixed. According to variation of demographic characteristics of out-migrants, households com-position may change in different ways. This paper aims to enumerate the size of out-migration and clarify the change of households composition, using the residents-registry on Sakushima (Mikawa-Bay, Aichi-Prefecture) from 1955 to 1977. Here the out-migration are classified into 4 types as follows:(A) Migrants move alone and he or she is a part of members of his or her household on Salcushima.(B) Migrants move alone and he or she is a sole member of the household on Sakushima (at the time of out-migration, he or she lives alone).(C) Migrants move together with other members of his or her household and they are a part of members of their household on Sakushima.(D) Migrants move together with other members of his or her household and they themselves consist of the household. The type of out-migration by age is as follows:(1) Out-migrants of age 0-14 mainly belong to type (C) and (D).(2) Out-migrants of age 15.29 account for over 70% of all out-migrants and over 90% of them belong to type (A).(3) Out-migrants of age 30.44 belong to type (C) and (D).(4) Outrmigrants of age 45-59 belong mainly to type (C) and (D), even though type (B) accounts for over 30%.(5) Almost 70% of out-migrants of age 60 and over belong to type (B). The main streams of households composition change are due to following threeways:(1) A couple and their child(ren) → A couple only(2) Parent and his or her child(ren) → One-person household(3) A couple - One person household In spite of the main stream toward one-person household in the observation periods, the number of one-person households has not increased since 1970. It has been resulted from the increase of out-migration of type (B). This change of households composition side-by-side with the aging of population after a continuous out-migration of younger ages may create an another phase of out-migration.
Under the assumption that there are no differences between males and females in the risk or probability of dying, the sex ratio of mortality rates is necessarily 1:1. The mortality rates, however, are actually different between both sexes and the sex ratio of mortality rates is rarely 1:1. B. MacMahon and T.F. Pugh 1) described that mortality rates are higher for males than for females at all ages except in particular areas where the obstetrical care is poor. However it is interesting to note that more males are born alive than females. H. Nagata2) pointed out in his paper that the sex ratios of mortality rates in Japan today are rising in comparison with those between 1955 and 1959, and those between 1968 and 1972. He thought that this came from not biological differences (physiological or anatomical), but environmental factors related to socio-economic conditions. He tried to confirm his hypothesis in a later paper by a comparative study between nations.3) The purpose of this present study is to compare the sex ratios of mortality rates from major causes in urban areas with those in rural areas, and to consider the background or causes of sex differences in mortality rates.Materials and Methods Tabulated data in The Special Report of Vital Statistics 1975, 4) published by the Department of Statistics and Information, Ministry of Health and Welfare, Japanese Government, was used for the analysis in this study. In this report age adjusted death rates from causes were calculated by the direct method using the population of Japan in 1960 as the standard population. Data was divided into two parts; one urban, the other rural. The former was those areas classified administratively as cities, the latter the areas excluding cities. The classification is thought to be consistent with the degree of urbanization. The sex ratio of mortality rates was used as an index of differences between males and females in mortality rates. It was given through division of the mortality rates for males by the mortality rates for females.