Suchergebnisse

SummaryThis article examines the mechanisms of subsistence adaptation of two Papua New Guinea populations, the Metroxylon sago-depending lowland Gidra and the taro-monoculture Mountain Ok, surviving in low population densities of 0·5 and 1·4 persons per km2. Observation of the groups' land use systems strongly suggests that their population densities have not been far below the carrying capacity, although the territory of each population is markedly heterogeneous. Both groups have maintained their sustainable food production not only for resource management but also for survival at a population level, either expanding their territory or changing the sustainable level in tandem with changes of subsistence system.

The Sundanese inhabiting West Java, the second largest ethnic group in Indonesia, are characterized by a high prevalence of child malnutrition, together with high fertility. Based on an anthropometric measurement and interview survey of 310 children aged 5–12 years in a rural Sundanese village, this study examined the relative significance of the effects of eight biological, eight socioeconomic status (SES) and four health behavioural factors on their Z scores for height-for-age (HAZ) and weight-for-age (WAZ) in particular. Three biological factors, i.e. birth interval, birth weight and mother's body weight, and one SES factor, i.e. mother's occupation, were selected as the predictors of the two Z scores by regression analysis, indicating more significant effects of the biological factors than the other factors. This pattern is judged to occur in less-developed and high-fertility populations. Since these two Z scores were worse in the subject children than in the under-5-year-old children from the same village, more attention should be paid to the long-lasting effects of birth-related biological factors up to pre-adolescent ages, as an insufficient nutritional status tends to damage growth and health in adolescence and adulthood.

Based on the authors' interview survey for 608 randomly selected women of the rural Arab population in the South Ghor district of Jordan, this paper examined the effects of polygyny and consanguinity on high fertility, which was recognized as natural fertility. The prevalence of polygynous and consanguineous marriages was 28·0% and 58·1%, respectively, largely reflecting the population's traditional marriage customs. The findings highlighted a significantly higher total marital fertility rate (TMFR) in the monogamous wives (10·5) than in the senior polygynous (8·1) and junior polygynous wives (8·6); the TMFR did not significantly differ among the wives of non-consanguineous, first-cousin and second-cousin marriages. The formation of polygynous marriage was decided by the husband, mostly as a result of his senior wife's infecundity or sub-fecundity, and the age of the husband at marriage to his junior polygynous wife was high in many cases, leading to a decline in this wife's fecundity.

Time spent on subsistence activities was compared between rural sedentes and urban migrants of the Huli population in Papua New Guinea. Person-day observation data were collected for rural sedentes (441) in the Tari basin and for urban migrants in Port Moresby (175). The time spent on subsistence activities by males was longer in the urban area than in rural areas, while that by females was similar in both areas. Conspicuous gender inequality with respect to labour hours in rural areas seems to diminish when people move to urban areas, reflecting the different subsistence regime between rural and urban environments.

In Tokyo Megalopolis, long-distance commuting between residences in the suburbs and work places in the centre of the city was examined. Using a questionnaire, heads of household in two suburbs were asked about the influences of long commuting hours on their daily time budgets. The results showed that on workdays, the workers who spent longer commuting rose and left home for work earlier, and came back home and retired later; accordingly, both time spent on in-home activities on workdays and hours slept on the day before a workday were shorter. Comparison of time budgets between the subjects who work 5 and 6 days per week revealed more vulnerable influences of long commuting hours in the former than the latter. The expected health consequences of these findings are discussed from a biosocial/human ecological viewpoint.

SummaryIn the Kingdom of Tonga, migration to overseas developed countries has prevailed. To elucidate the effects of migration on population dynamics, an interview survey was conducted in the migrant-sending community of Kolovai, in the outer region of Tongatapu Island. All births, deaths, marriages and in- and out-migrations that took place between 1983 and 2002 were recorded for all members of the 'Kolovai population', consisting of persons who had lived in this community for at least a one-year period during this 20 years. The 'Kolovai population' members, numbering 1184 (564 males and 620 females), were divided into three groups based on residence at the end of each year, i.e. Kolovai (called KK), other places in Tonga (KT) or overseas countries (KO). The KK population decreased from 774 in 1982 to 570 in 2002, owing mostly to an increase of 167 persons as the natural balance and a decrease of 324 persons as the balance of international migration. Comparison of total fertility rate (TFR) between KK and KO women revealed that the mean TFR of the former decreased from 3·460 in the earlier 10-year period (1983–1992) to 2·240 in the later 10-year period (1993–2002), while that of the latter was more than 3·5 in both 10-year periods. This difference was largely due to the decrease in the proportion married among KK women. If the current trends of international migration and fertility continue, the population of Kolovai will be reduced and its age composition will become cylinder-shaped in the near future.

The use of contraceptives has become prevalent among females in Thailand in the past 20 years, and oral contraceptive use has been suggested to trigger changes in fat intake, energy expenditure, fat metabolism and blood pressure. Based on field investigations of 391 married women aged 20 years or over in Yasothon Province, North-east Thailand, this study aims to elucidate the effects of oral contraceptive use on body mass index (BMI: kg/m2 ) and blood pressure, taking into account reproductive histories and socioeconomic conditions. The proportion of obese (BMI> 25) subjects was high in the age groups 30–39, 40–49 and 50–59, accounting for, respectively, 39·4%, 51·1% and 48·5% of these populations. The proportion of women with hypertension (90/140 mmHg) was 23·7%, 18·5% and 26·2% in the 40–49, 50–59 and 60–69 age groups. Current contraceptive practices in the studied population included sterilization by operation, oral contraception and injection. These methods accounted for 43·0%, 12·8% and 8·2% of the population, respectively. Sociodemographic factors such as reproductive history, years of education and household income were not significantly related to BMI or to blood pressure (ANOVA with age adjustment). In contrast, oral contraceptive users had significantly higher BMIs and diastolic blood pressures (p<0·01, ANOVA with age adjustment). Multiple regression analysis also revealed that oral contraceptive use was a weak but significant contributing factor to both high BMI and blood pressure when sociodemographic factors were taken into account and controlled for statistically. It can thus be concluded that the use of contraceptive pills, which contain oestrogen and progestin and are provided free of charge to Thai women, tend to increase BMI and to elevate blood pressure.

The compact spot-check method was applied to elucidate the daily time and space use patterns of 121 adults from a Bangladeshi village in which the authors had previously found more skin manifestations due to arsenic poisoning in males than females. The analysis of 2178 spot-check data, which were obtained over a net period of 2 days, highlighted that farming and cash-earning activities were almost exclusively conducted by males. This is probably due to the Muslim Bangladeshi norm for females to be 'sedentary' in or around their own dwellings. Discussion focuses on the advantages of the compact spot-check method and the possibility that males' larger energy expenditure and longer exposure to sunlight are responsible for their severer skin manifestations.