This study investigates how various social, demographic and economic factors affect spousal agreement on preferred waiting time to next birth. Data for matched cohabiting couples from ten Demographic and Health Surveys in sub-Saharan Africa (Benin, Burkina Faso, Ghana, Guinea, Mali, Ethiopia, Kenya, Mozambique, Zambia and Zimbabwe), conducted between 2003 and 2006, were analysed to compare reported waiting time to next birth by the husband and the wife. Couples where the reported waiting time to next birth was the same for both partners (difference is 0 months) were defined as having agreement on waiting time to next birth. In sub-Saharan Africa, spousal agreement on waiting time to next birth was found to be associated with wanting the next child sooner. When the spouses disagree on waiting time to next birth, the wives want to wait longer than their husbands in most cases. Additionally, the study found that demographic factors are the primary determinants of spousal agreement on waiting time to next birth, not socioeconomic factors. The strongest predictors of spousal agreement on waiting time to next birth were number of living children, difference between the number of ideal and living children and wife's age. Couples with fewer children, a younger wife and those with a difference of five or more children between ideal and living number of children were more likely to agree on waiting time to next birth. Effects of socioeconomic factors, such as education and wealth status, on spousal agreement on waiting time to next birth were generally weak and inconsistent. The findings highlight some of the challenges in developing programmes to promote spousal communication and birth spacing and underscore the need for programmes to be gender-sensitive.

Natural selection and genetic drift are two evolutionary mechanisms that can be analysed in human populations using their fertility and mortality patterns, and their reproductive size and isolation, respectively. This paper analyses the models of natural selection and genetic drift in Bayárcal, south-east Spain, and compares them with the observed models in the rest of the Alpujarran region. Demographic data were obtained from a sample of 77 families (48.45% of the population, with 547 inhabitants). The genetic drift and natural selection action was evaluated with the Coefficient of Breeding Isolation (CBI of Lasker and Kaplan) and Crow's index, respectively. The CBI (23.23/12.61) suggests that genetic drift is near to acting, and Crow's index (I=0.58) is slightly higher than that observed in the rest of La Alpujarra. Although the reproductive isolation of Bayárcal is not effective enough for genetic drift to act, it is near when marital migrants inside the Bayárcal valley are considered as a native population. The natural selection pattern is not different from that of the rest of La Alpujarra, but it tends towards the model of developing communities, where the demographic transition has not yet begun.

Most studies on consanguinity have been conducted on contemporary populations and have focused on the prevalence and types of preferred intra-familial marriage. With its comprehensive birth, marriage and deaths records dating back to the late 17th century, and the legal bar on first cousin marriage removed in the mid-19th century, Sweden offers unique opportunities to examine the factors that determine by whom, where and why consanguineous marriages were contracted. The present study covers the period 1780–1899 and presents a detailed portrait of cousin and sibling exchange marriages in the Skellefteå region of northern coastal Sweden. The combined prevalence of first, second and third cousin marriage increased from 2.3% in 1790–1810 to 8.8% in 1880–1899, and multi-generation consanguinity also increased significantly over the study period. The distribution and prevalence of first cousin marriages was strikingly non-random, with a significantly greater propensity for consanguinity among land-owning families, especially involving first-born sons, within specific pedigrees, and in a number of more remote inland communities. Additional factors associated with a greater likelihood of consanguineous marriage included physical or mental disability among males, and among females the prior birth of an illegitimate child. Besides the inherent interest in the social and demographic structure of this region of northern Sweden during the course of the 19th century, in future studies it will be important to determine the degree to which the observed patterns of consanguineous and sibling exchange marriages in these past generations could have influenced present-day genetic structure.

This paper examines the impact of childhood malnutrition on schooling performance in rural Bangladesh. The results reveal that malnourished children are less likely to enrol in school on time and achieve an age-appropriate grade by 26 percentage points and 31 percentage points, respectively. Other important determinants of schooling outcomes include infrastructure and education level of parents. One major contribution of this paper is the control for the endogeneity of malnutrition status, which otherwise might lead to bias estimates.

The aim of this study was to identify the characteristics of individuals who formed exogamic marriages in the Friuli region (north-east Italy) during the second half of the 19th century. Logistic regression models were devised to measure the influence of the determinants of exogamic marriage, taking into account not only variables related to context but also spouses' economic, social and cultural characteristics. The determinants of exogamic marriage differ for men and women, and also vary by region due to differences in geographical mobility and size of the marriage market. The majority of exogamic spouses belong to one of two categories: either older individuals, often, especially in the case of men, with a previous marriage; or the upper social classes.

Data for Raven's Progressive Matrices are reported for a sample of 6290 6- to 17-year-olds in Taiwan. The Taiwanese obtained a mean IQ of 109.5, in relation to a British mean of 100. There was no difference in mean scores of boys and girls at age 7 years. At age 10 years girls obtained significantly higher scores than boys, and at ages 13 and 16 years boys obtained significantly higher scores than girls. There was no sex difference in variance at age 7 years. At ages 10, 13 and 16 years variance was significantly greater in boys.

In order to investigate the association between mean inbreeding coefficient (α) and healthy life expectancy at birth (HALE; years) the present ecological study on 63 countries was done. Statistical analysis showed that HALE negatively and positively correlated with log10α and log10GNI per capita, respectively (p<0.001). It should be noted that log10α and log10GNI per capita were significantly correlated with each other (p<0.001). After controlling for log10GNI per capita, significant negative correlations between log10α and HALE were observed. The countries were stratified according to their GNI per capita into low- and high-income countries. In countries with high income, after controlling for log10GNI per capita, the correlation between HALE at birth and log10α was significant (for males r=−0.399, df=32, p=0.001; for females r=−0.683, df=32, p<0.001). In high-income Asian and African countries, where consanguineous marriage is common, after controlling for log10GNI per capita, the correlation between HALE at birth and log10α was significant (for males r=−0.819, df=8, p=0.004; for females r=−0.936, df=8, p<0.001). It seems that consanguinity influences HALE independent of country income.

This study aimed to assess the effectiveness of intervention (specifically, intervention by telephone and mails, known as ‘tele-care’) relative to self-help as a weight-loss method. The question of whether there is a correlation between changes in two preference parameters – time discounting (i.e. impatience) and risk aversion – and the level of commitment was examined. The study, spanning a period of 24 weeks in 2006–2007, comprised 118 participants, each of whom was randomly assigned to either the tele-care or the self-help group. A public-health nurse provided support through telephone and mail communications to the tele-care group, aiming to reduce their calorie intake and increase exercise via this intervention. There was a significant decrease in the body weight of the participants of the tele-care group from the baseline; however, there were no significant differences in the weight loss, median time discounting or risk aversion between the two groups. The subsequent analysis for weight loss with changes in time and risk parameters revealed a significant difference in the weight loss in the time-discounting–loss and risk-aversion–gain groups. From the results of the multiple regression analysis, the time discounting was noted to be associated with age, initial BMI and marital status among men, and risk aversion was associated with age and job status among women. There is a possibility that a decrease in time discounting and increase in risk aversion might correlate with the weight loss or effectiveness of commitment in this trial. This study suggests that time discounting and risk aversion may be useful in anti-obesity efforts, since they are accurate criteria of behavioural patterns associated with weight problems.