Sterilisation has been increasing in the United States in recent decades. Using the National Survey of Families and Households, this paper examines sterilisation among married couples using event history techniques, viewing husband and wife sterilisation as competing risks. Wives are more likely to experience sterilisation and at shorter durations of marriage. Number of children has a curvilinear effect on sterilisation, increasing and then decreasing its likelihood. Wives who are older than their husbands are more likely to get sterilised themselves. Black and Hispanic husbands are more likely to undergo sterilisation.

Low serum 25-OHD in female Arab subjects, which may predispose their infants to hypocalcaemia, has been suggested to be due to inadequate sunshine exposure, but may include other sociobiological factors. The effects of duration of sunshine exposure - weighted against the magnitude of clothing (UV exposure) and other sociobiological variables such as age, education and living accommodation - on serum 25-OHD and mineral status of 33 UAE national women of childbearing age were compared with those of 25 non-Gulf Arabs and seventeen Europeans. Serum concentrations of calcium, phosphorus, alkaline phosphatase and intact parathyroid hormone among the groups were not significantly different. The serum concentration of 25-OHD in UAE nationals was 8·6 ng/ml (4·5–17·4), mean±1 SD, and in non-Gulf Arabs 12·6 ng/ml (6·0-26·4); both these values were significantly lower (p=<50·0001) than the 64·3 ng/ml (49-84·3) found in Europeans. Compared with Europeans, the UAE and non-Gulf Arabs in this study were younger, had fewer years of education and had significantly lower clothing and UV scores (p<0·0001). Furthermore, there was a positive correlation (r=0·59425) between serum 25-OHD and UV score, but not with length of exposure. After adjusting for other confounding variables, nationality, clothing and UV scores remained major determinants of serum 25-OHD (p<0·0001). Therefore, limited skin exposure to sunlight appears to be an important determinant of vitamin D status in our subjects. Strategies to increase vitamin D stores should include vitamin D supplementation or advice on effective sunlight exposure.

Data from a 1993 household survey in rural Sierra Leone revealed that, among women aged 12-49 with at least one child younger than 5, about 13% were using a contraceptive method and about 67% wanted more children. These rates differ from those reported for the 1980s and 1970s, when the contraceptive use rate was around 6% and more than 85% of women desired more children, suggesting a trend towards fertility limitation over the years. Logistic regression analysis showed that contraceptive use was positively associated with age, number of living children, age at marriage, education, and economic status, and negatively associated with Islamic and traditional religious affiliations. Government and other health clinics, hospitals, and government paramedical personnel were the major sources of contraceptive supplies. The lower desire for more children might relate to demographic pressure from the recent improved child survival rate compounded by recent economic hardship.

This study examines the impact of nutritional status, classified by body mass index, on sex specific fat distribution patterns dependent on menopausal status in 467 pre-, peri- or postmenopausal females. Absolute and relative amounts of upper and lower body fat were estimated by means of dual energy X-ray absorptiometry. It was found that low weight, independent of menopausal status, leads to the typical gynoid pattern of fat distribution while excess weight and obesity result in the android pattern of distribution in pre- and postmenopausal women.

The exogenous cycles and population dynamics of the community at Penrith, Cumbria, England, have been studied (1557-1812) using aggregative analysis, family reconstitution and time series analysis. This community was living under marginal conditions for the first 200 years and the evidence presented is of a homeostatic regime where famine, malnutrition and epidemic disease acted to regulate the balance between resources and population size. This provides an ideal historic population for an investigation of the direct and indirect effects of malnutrition. Throughout the period studied, a short wavelength oscillation in grain prices was apparently the major external factor that drove exogenous cycles in mortality, birth rate, and migration. In particular, the different responses of children to variations in food supply are emphasised; fluctuations in poor nutrition correlated significantly with the variations in mortality rates for infants (probably indirectly during pregnancy and directly during the first year of life) and for young children (via susceptibility to lethal infectious diseases). Migratory movements contributed to the maintenance of homeostasis in the population dynamics. A medium wavelength cycle in low winter temperatures was associated with a rise in adult mortality which, in turn, promoted an influx of migrants into this saturated habitat. A model incorporating these interacting associations between vital events and exogenous cycles is presented: grain prices were an important density-dependent factor and constituted the major component of the negative feedback of this population and drove the exogenous, short wavelength mortality cycles. Cycles of births and immigration provide a positive feedback for the build-up of susceptibles and the initiation of smallpox epidemics and increased population size.

This paper studies the correlates of IUD continuation, particularly in relation to quality of service provided in Karnataka, South India, by using a discrete-time logit model. Provision of follow-up services had a moderate influence on continuation, and medical check-up at insertion influenced the experience of side effects. But these effects were trivial in comparison with the overriding influence of motivational variables and of reported side effects. The IUD is retained for a limited duration in rural India where it is used mainly as a spacing device by lowly motivated young women who discontinue the method at the slightest feeling of discomfort or abnormality. If the IUD were recommended to older women for limiting childbearing by emphasizing its reversibility, it would enhance the method's popularity and improve the levels of contraceptive use among younger women.

This study documents the impact of migration, environment and caste on the blood pressure of Sikhs living in the UK and their peers in the native Punjab state of India. A sample of 449 adult Sikhs, males and females, were studied in the Punjab state, and in Southall, in the Ealing borough of London and Handsworth in Birmingham in the UK. There is minor variation in the blood pressure of members of various castes among the Sikhs living in the Punjab. The pattern in blood pressure broadly corresponds with the economic status of the individuals, with well-off groups showing higher blood pressure compared to the poorer groups. The blood pressure of migrants, though higher than that of their sedente peers, is not significantly so. Age at arrival in the UK and the length of exposure to the new environment were generally not significantly related to variation in blood pressure. There seems to be a secular shift in the blood pressure values of the native Punjabi Sikhs compared to earlier studies, possibly because of the rise in civic disturbances and social unrest in the Punjab during recent years.

Information on reproductive attitudes is now routinely collected in fertility surveys in developing countries, and has become very important for understanding fertility behaviour. The quality of this information, however, is rarely assessed, partly due to lack of necessary data. In this paper, the recently completed panel survey in Morocco by the Demographic and Health Surveys (DHS) was used to investigate the consistency of reporting of ideal number of children, reproductive intentions and the planning status of the last birth. The validity of reproductive intentions for subsequent fertility behaviour was also examined. The findings indicate that the three measures of reproductive attitudes are subject to different degrees of measurement error. The measure of reproductive intentions is the most consistent of the three, followed by ideal number of children. The latter is much more consistent at the aggregate level than at the individual level. The reliability of the planning status of the last birth is marred, mainly by an unwanted child being reclassified as 'wanted' with time since the birth of the child. The reproductive intentions of women were also found to be positively related to their subsequent fertility.

This paper examines the seasonality of induced abortion in North Carolina between 1980 and 1993. Distinct seasonal patterns are found, with a peak in February and a valley in September. These patterns correspond to the implicit seasonality of conceptions associated with the seasonality of birth pattern. One notable difference from the general pattern is among unmarried women aged 18 and younger. They have the February peak and an additional peak in August that may be associated with the summer vacation from school.

The existence of very low rates of fertility among non-contracepting human populations has intrigued researchers in demography and reproductive ecology. Long inter-birth intervals, driven primarily by the lactational amenorrhoea associated with breast-feeding, have been shown to be important determinants of low natural fertility in several populations. Other reports have suggested that sterility brought about by sexually transmitted diseases (STDs) might also explain low fertility in some populations, especially in Africa. This report presents an analysis of 1981 Indian census data that documents low natural fertility in Ladakh, a high-altitude region of the Himalaya in north India. In Ladakh, there is evidence for low rates of marriage among women that may be attributable to the practice of polyandry, but also high rates of primary and secondary sterility within marriage, resulting in low completed parities for post-reproductive age married women. Age-specific fertility rates derived from the number of current births are also unexpectedly low. Hypotheses to explain very low fertility in Ladakh are considered from among the likely proximate determinants and evaluated using two supplementary sources of information derived from fieldwork in Ladakh in the early 1990s. The most likely explanations for low marital fertility include sterility from STDs, high rates of fetal loss, and possibly nutritional contraints on ovarian hormone status.

The Food Choice Questionnaire (FCQ), which measures the reported importance to a given individual of nine factors underlying food choice, and a food frequency questionnaire, were administered to 241 participants, who were also required to classify their diet as either 'standard', 'low in red meat' or 'vegetarian'. Respondents describing their diet as low in red meat attributed greater importance to health, natural content, weight control and ethical concern in their food choice than did those who described their diets as standard, whereas vegetarians differed significantly from those with a standard diet only on the score for ethical concern. Differences between men and women and between students and non-students in the frequency of consumption of a number of foods were shown to be mediated by differences in the importance attached to FCQ factors. Thus the generally healthier diets of women compared to men appeared to be accounted for by the greater importance attributed by women to weight control, natural content and ethical concerns.

Using nationally representative data, it is shown that marital unions are relatively stable in Nigeria. Remarriage rates are high so little time is lost between unions. Consequently, the fertility of women who have experienced marital disruption is only slightly lower than for those in stable unions. Their slightly lower parity may be a function of a high incidence of reproductive impairment, which is a major reason for divorce and separation in Nigeria.

A procedure for assessing birth spacing goals, an important component of fertility preferences, is proposed and applied to 1993 Costa Rican data. Based on a reverse or backward survival analysis, preferred birth intervals are estimated to range between 3·5 and 4·5 years (1·5 years for the interval union to first birth). These intervals are 2 or 3 years shorter than crude estimates from data on open or last closed intervals, which are upwardly biased by selection and left censoring effects. To achieve these spacing preferences, a cohort must spend about two-thirds of the time using contraception (one-third in the interval union to first birth). An inverse association between desired family size and desired birth interval is evident only in parity-specific analyses.

Some factors affecting marital distances have been studied in two Outer Hebridean islands, Harris (843 marriages) and Barra (444 marriages), over the period 1855-1990. In each island marital distances fell before 1900, but then rose to their greatest values after the 1950s. Fishermen generally married at the shortest distances and men in land-based occupations at the longest. The depression in the fishing industry during the 1880s and early 1890s was associated with reductions in marital distances, especially among fishermen. In the different regions of Harris, marital distances were least in the south-east, where settlement was most dense, and greatest in the south-west where it was most sparse.

When the association between marital frequencies and inter-settlement distances was studied, it was found that for Harris there was, overall, a trend to endogamous and short-distance marriage. However, this trend was only slight during 1955-90. For Barra a similar trend was found before 1955, but thereafter there appeared to be virtually no connection between marital frequency and inter-settlement distance. Thus the only constraint on marriage was the spatial distribution of settlements. In this situation the chances of random mating with respect to distance are maximised.

Application of ‘Central Place’ theory suggested that only since 1946 can any tendency be detected to regard Tarbert in Harris or Castlebay in Barra as Central Places, at least as far as marriage is concerned. In each island the tendency appears to be limited to the settlements closest to the Central Place.

This study examines whether mortality of two adjacent siblings in families is age-specific and is modified by the MCH–FP programme and fertility and mortality declines in Matlab, Bangladesh, using data for singleton births during 1977–78, 1985–86 and 1989–90 in the treatment (MCH–FP) and comparison areas. Logistic regression was used to estimate the net effects of survival status of elder siblings on mortality of younger siblings in the neonatal, postneonatal and toddler periods, controlling for birth order, previous birth interval, maternal age, education and religion, household possession of valuable items and sex of the child.

Odds of neonatal and postneonatal deaths of younger siblings were found to be higher if the elder sibling had died at the same age than if the sibling had survived infancy. Toddler mortality was lower if the elder sibling had died in infancy. The association between two siblings' mortality risks did not decline over time in either area. The results suggest that a family history of child deaths by age is important to identify when subsequent infants would be at a higher risk of dying.

Breast-feeding and weaning practices were observed for a cohort of 81 children under 3 years of age in the context of a longitudinal study of social, ecological and nutritional factors affecting growth in a semi-nomadic population of pastoralists in northern Tanzania (WaDatoga of Mbulu District). The adequacy of indigenous infant and young child feeding practices was assessed in relation to current international recommendations. Objectives were to provide baseline data for future investigations of any changes in young child feeding practices which accompany population shifts towards settlement and non-pastoral modes of subsistence, and to improve understanding of the strengths and limitations of indigenous feeding practices in this type of population. It was found that while breast-feeding was universally initiated, other aspects of young child feeding practices do not meet current international recommendations. Prelacteal feeds are commonly used, supplementary feeding with non-human milks usually occurs before 4 months of age, use of solid foods normally begins later than 6 months, and breast-feeding does not continue until 2 years of age for the majority of children. The data have implications for the design of breast-feeding promotion and improved weaning food interventions among African pastoralists.

The purpose of this study was to assess factors associated with the use of family planning at first sexual intercourse among young adults aged 15 to 24 in urban Ecuador. The study population consisted of 1443 young adults (494 females and 949 males) in the cities of Quito and Guayaquil, interviewed by the 1988 Ecuador Young Adult Reproductive Health Survey, who reported having experienced consensual sexual intercourse. Approximately 11% of females and 15% of males reported using contraception at first intercourse. Binary logistic regression was performed to assess jointly the effect of multiple factors on contraceptive use at first intercourse. The regression model was first run on the entire study population and then separately for males and females. In the overall population, the following variables were significantly related to using family planning at first sex: being male; being from Guayaquil; older age; father's completion of secondary school. Having lost one's virginity to a prostitute was significantly associated with non-use of family planning. Males were 3·6 times more likely than females to use family planning during their first sexual intercourse. For each year older a young adult was at first sex, his or her odds of using family planning was multiplied by a factor of 1·3. Twenty-eight per cent of males in this study experienced their first sexual intercourse with a prostitute, and these young men were highly unlikely to use family planning. A male who experienced first intercourse with his girlfriend was more than five times as likely to use contraception than a male who lost his virginity to a prostitute.

This paper explores a number of socioeconomic factors thought to explain the wide prevalence of undernutrition among rural Bangladeshi women. The 1992 baseline survey data of the BRAC-ICDDR,B Joint Research Project at Matlab were used. Anthropometry was performed on a random sub-sample of 1462 currently married, non-pregnant women between 15 and 49 years of age. Women's nutritional status was defined in terms of Body Mass Index (BMI=wt in kg/ht in m2). Compared with women from better-off households, the mean weight (41.2 vs 43.0 kg; p<0.0001), mid-upper arm circumference (MUAC) (22.1 vs 22.7; p<0.0001), and BMI (18.5 vs 19.1; p<0.0001) of poor women were consistently lower. However, no significant difference in mean height was found between the two groups. The results showed that women aged more than 35 years are twice as likely to have a BMI<18.5 compared with younger women. Both years of schooling received and socioeconomic status are found to be important predictors of women's BMI. Women who have received one or more years of formal education are nearly half as likely to suffer chronic energy deficiency (BMI<18.5) than women with no schooling. Again, better-off women are found to be 0.77 times less likely to have chronic energy deficiency than women from poor households. The implications of these findings in improving the nutritional status of rural Bangladeshi women are discussed.

This paper discusses ways in which empirical research investigating sexual networks can further understanding of the transmission of HIV in London, using information from a 24-month period of participant observation and 53 open-ended, in-depth interviews with eighteen men and one woman who have direct and indirect sexual links with each other. These interviews enabled the identification of a wider sexual network between 154 participants and contacts during the year August 1994-July 1995. The linked network data help to identify pathways of transmission between individuals who are HIV+ and those who are HIV−, as well as sexual links between ‘older’ and ‘younger’ men, and with male prostitutes. There appears to be considerable on-going transmission of HIV in London. The majority of participants reported having had unprotected anal and/or vaginal sex within a variety of relationships. The implications of these findings for policies designed to prevent the transmission of HIV are discussed.

This paper reviews the results of clinical trials and community studies of lactational amenorrhoea and its role as a contraceptive method (LAM). Indicators which are used in efficacy trials and effectiveness interventions are compared and sets of indicators of effectiveness appropriate to community-based LAM programmes are recommended. A five-tiered ecological framework is used to facilitate selection of indicators which range from individual to policy level outcomes. The indicator framework is intended as a tool for health practitioners in family planning and maternal and child health service delivery settings who are interested in designing programmatic interventions for the promotion of LAM, particularly among less well-educated women of lower socioeconomic communities.