Early sexual debut is of major concern because it is a correlate for health and economic shocks experienced in adulthood. In South Africa, this concern has provided impetus for research directed at the HIV and AIDS epidemic, teenage pregnancy and the effect of adolescent sexual behaviour on persistence in school. Of interest to the present study is high school completion, which is a well-established empirical barometer of adult socioeconomic opportunities. Using data from the five waves of the Cape Area Panel Study (CAPS), this paper examines the association between sexual behaviours initiated in pre- and early adolescence and high school completion rates. The CAPS study is a longitudinal survey that was designed to investigate young people’s (aged 14–22 years) educational attainment and sexual behaviours in Cape Town, South Africa. The sample was constituted from 3213 individuals who had initiated sex during their teenage years and the analysis was undertaken when the youngest cohort was aged 21, an age at which they should have completed high school if they were on time. Logistic regression models were fitted separately for males and females. Overall, the results reveal that early sexual debut is correlated with long-term negative educational outcomes. Individuals who experience early sexual debut are less likely to complete high school than their counterparts who make their sexual debut later on in life. This effect is worse for Africans, who also disproportionately have an earlier sexual debut than other race groups. Apart from race however, the findings also reinforce the effect of other demographic factors on high school completion, namely, place of residence and family socioeconomic status as measured by parental education and household income. Hence, early sexual debut adds another layer of inequality and worsens the plight of Africans, females, those living in rural areas and those who come from low-income families.

Employing the Indonesian Family Life Survey, this paper depicts the trend in age at menarche in Indonesia for women born in 1944–1988. Mean age at menarche decreased from 14.39 years for birth year 1944 to 13.18 years for birth year 1988. Subsequently, this trend is related to the improvement in material conditions, measured by GDP per capita in childhood. The OLS results indicate that this decrease is largely explained by the improvement in material conditions. If age at menarche is considered an indicator of biological standard of living, these results suggest that the improvement in material conditions during the period converted to an improvement in biological standard of living.

The aim of this study was to examine the changes in body composition (fatness and muscle and bone mass) and BMI in three cohorts of boys living in Krakow, Poland, over the last 30 years, and to assess how overweight and obesity frequencies have developed over the period. The anthropological survey was conducted in 2010, and comprised 1863 boys from Krakow aged 3–18 years. The analysis compared the latest measurements of selected skinfold thicknesses, BMI, total body muscle mass and bone mass with the results of surveys from 1983 (N=1934) and 2000 (N=2323). The frequency of overweight and obesity was assessed for the last survey series, and their trends determined for the years 1983–2000 and 2000–2010. The analysis of fat tissue distribution showed that the boys from the 2010 cohort, as compared with those examined in 2000, had a higher trunk adiposity, as manifested by greater thickness of subscapular and suprailiac skinfold thicknesses, and boasted a larger muscle mass and lower bone mass. The survey results also showed that, from 1983 to 2000, the percentage of overweight boys increased slightly (from 11.69% to 12.48%), whereas the frequency of obesity did not change. Over the last decade, the percentage of overweight people has increased to 15.94%, and the frequency of obesity has doubled, equalling 4.94% in 2010. The last decade has seen a minor trend in boys towards increased trunk adiposity, muscle mass, BMI and prevalence of overweight and obesity, and a slight decrease in bone mass.

The aim of this study was to assess whether women’s empowerment ensures reduced intimate partner violence (IPV). The differential relationship between women’s empowerment and IPV among married women in Bangladesh was investigated using 2007 Demographic and Health Survey data. Logistic regression models were used to assess whether women’s empowerment had any influence on their likelihood of experiencing IPV while controlling for other covariates. The analyses revealed that older cohorts of women, who were more empowered, were more vulnerable to physical violence than less-empowered, younger women. The likelihood of being affected by physical violence among less-empowered, childless women was greater than that of more-empowered women with only male children. Less-empowered, uneducated women were more likely to experience physical violence than more-empowered, primary-educated women. Less-empowered women who had been married for less than 5 years were more likely to suffer from physical violence than more-empowered women who had been married for more than 19 years. The likelihood of experiencing sexual violence was not found to have any significant association with women’s empowerment. The findings suggest that although women’s empowerment in Bangladesh is gradually improving, some sub-groups of empowered women are still susceptible to IPV.

Urinary cortisol and adrenaline excretion rates were measured in three Australian Aboriginal communities in the Kimberley region in the north-west of the country. The three communities, Derby, Kalumburu and Kupungarri, differ in size and remoteness and some lifestyle parameters. Cortisol excretion rate is associated with age and urine flow rate, but there is no association with smoking or the consumption of alcohol. All three communities show very high cortisol excretion rates compared to a sample of UK (Oxford) residents and there are also differences between the three communities. Adrenaline excretion rate also shows associations with age and urine flow rate, but not with smoking. Aboriginal people in the Kimberley region excrete adrenaline at a slightly higher rate than that found in Oxford, which itself is high by world standards. There are no marked differences between communities in their adrenaline excretion rates. Alcohol drinkers in Derby, where alcohol is freely available, have higher adrenaline output than non-drinkers.

From an evolutionary perspective, childlessness may be considered a failure, as it implies that there will be no direct transmission of one’s genetic material to later generations. It is also a pressing social issue, because in many contemporary advanced societies, levels of childlessness have increased, and particularly so among men. The absence of a partner is naturally a fundamental determinant of childlessness. Empirical evidence on how childlessness relates to individuals’ partnership histories is nevertheless limited. This issue was analysed with Finnish population register data, which allow the complete cohabitation and marriage histories of individuals from age 18 years to be observed. For women and men born between 1969 and 1971, logistic regression models were estimated for childlessness at age 40 by partnership histories in terms of various stages in the process of union formation and dissolution, and accounting for several socioeconomic variables. A strong link between union histories and childlessness was found, with short partnership spells raising the risk of not becoming a parent. Later age when leaving the parental home raised female childlessness, while a short first-union duration related more strongly to male childlessness. These findings may be considered as providing insights into how specific life-history strategies affect reproductive outcomes, and highlight the need to develop new approaches to understand this feature of social inequality.

The status of women, which is relative and multidimensional, has an important bearing on any long-term reduction in fertility. In Indian society, where cohabitation and childbearing are socially sanctioned only after marriage, the length of the first-birth interval affects the completed family size by influencing the spacing and childbearing pattern of a family. This study examines the influence of certain aspects of the status of married women – education, employment, role in family decision making, and age at marriage – along with three socioeconomic variables – per capita income of the family, social position of the household, and the caste system – on the duration of the first-birth interval in an urban Hindu society of the north-east Indian state of Assam. The data were analysed by applying life table and hazard regression techniques. The results indicate that a female's age at marriage, education, current age, role in decision making, and the per capita income of the household are the main covariates that strongly influence the length of the first-birth interval of Hindu females of urban Assam. Of all the covariates studied, a female's education appears to be a key mediating factor, through its influence on her probability of employment outside the home and thereby an earned income and on her role in family decision making. Unlike other Indian communities, the effect of the caste system does not have a significant effect on first-birth timing in this urban Hindu society.

A sample of 170 Regina school children, divided into subgroups according to family size and socio-economic status, was tested on the Otis Beta Mental Ability Test. The results demonstrated the existence of a definite relationship between intelligence and socio-economic status, but no significant relationship between family size and IQ, except among low socio economic status males. These results, interpreted as reflecting the changing relationship between intelligence and family size, are possibly the outcome of a changing fertility pattern within the various socio-economic status groups.

The increasing prevalence of negative body perceptions among adolescent girls and the tendency towards wishing to be thinner have become a cultural norm in Western culture. Adolescent girls are particularly vulnerable to developing a negative body image due to physical and sexual changes occurring during puberty. This study aimed to evaluate the association between different measures of body image perceptions and different phases of the menstrual cycle after controlling for weight status and other potential confounders in Polish adolescent girls aged 12–18 years. Three-hundred and thirty participants of a cross-sectional survey conducted in 2009, normally cycling and with no eating disorders, completed a background questionnaire and the Stunkard Figure Rating Scale, and their anthropometric measurements were collected. The dependent outcome variables were measures of body image (actual body image, ideal body image and ideal-self discrepancy) and dichotomous body image perception (satisfied versus dissatisfied) adjusted for other predictor factors: socio-demographic variables, menstrual history and cycle phases, and weight status. One-way ANOVA indicated that weight status, age at menarche and menstrual cycle phase were associated with actual body image and rate of ideal-self discrepancy. Ideal body image was associated with weight status and menstrual cycle phase. General logistic regression models were constructed to evaluate associations of body dissatisfaction and all potential predictor variables. The final selected model of the multiple logistic regression analysis using the backward elimination procedure revealed that adjusted for other factors, negative body image was significantly associated with different phases of the menstrual cycle (ptrend=0.033) and increasing body weight status (ptrend=0.0007). The likelihood of body dissatisfaction was greatest during the premenstrual phase of the menstrual cycle (OR=2.38; 95% CI 1.06, 5.32) and among girls in obesity class I (OR=8.04; 95% CI 2.37, 27.26). The study confirmed the association between body image dissatisfaction in adolescent girls and different phases of the menstrual cycle after controlling for weight status. The issue of negative body self-image is not only of cognitive, but also of practical value as understanding better the factors contributing to the formation of a negative body image may be instrumental in developing preventive health programmes targeted at young people.

This study examines the relationship between verbal, performance and total IQ scores and social class of 193 male householders living in a Cambridge suburb. The correlation coefficients between IQ scores and present occupational status were significantly higher than the correlations between IQ scores and social class of origin, suggesting that intragenerational social mobility is positively related to IQ.

Parent–offspring data were available for 85 father–son pairs. Analysis of the IQ differences between fathers and sons in relation to their social class differences provided further evidence for selective migration related to both IQ components and total IQ scores. In this sample there was a simple relationship between the extent of social mobility and the degree of difference between the father's and son's IQ scores.

The data from the Demographic and Health Survey conducted in Ghana in 1988 are used to identify determinants of immunisation uptake for children under 5 years. The logistic binomial analysis shows that socioeconomic factors are significant, especially women's education and region, and that the type of prenatal care received by the mother is also important. There is a strong familial correlation of vaccination behaviours, and there is also clustering of data within enumeration areas.

The primary objective of this report is to use data from a study of infant growth and weaning practices in Kathmandu, Nepal, to investigate universal recommendations about exclusive breast-feeding up to 6 months postpartum. A secondary objective is to demonstrate the complexity of the biocultural nature of infant feeding practices. A sample of 283 children under 5 years of age and their 228 mothers living in a peri-urban district of Kathmandu participated in this study. The children’s height/length and weight were measured three times over 9 months. At each session, a demographic, child health and infant feeding survey was administered; between sessions, in-depth interviews were conducted with mothers regarding infant feeding practices. While a few of the infants under 2 months were receiving non-breast milk foods, at 3 months of age half of the sample had been introduced to non-breast milk foods and by 7 months all infants were eating non-breast milk foods. A comparison of growth indices and velocities between exclusively and partially breast-fed infants from birth to 7 months of age shows no evidence for a difference in nutritional status between the two groups. Although there are cultural rules about breast-feeding that vary by ethnic group, all mothers followed a feeding method that depended on their assessment of whether the child was getting enough breast milk. The conclusion is that exclusive breast-feeding up to 6 months may not be appropriate for all infants. In this sample, breast-feeding duration is not shortened by the early introduction of non-breast milk foods, as the median age of breast-feeding cessation is 36 months. One of the main reasons for severance was the onset of another pregnancy. Investigation of infant feeding practices must be contextualized in the local ecology of the population. While cultural beliefs about breast-feeding are relevant, mothers’ individual assessments of their children’s nutritional needs and demographic events in parents’ lives must also be considered.

Seasonal or monthly fluctuations in suicides and homicides were analysed using US mortality data for the years 1969–78, using periodic regression analysis. The results were generally consistent (year-to-year) over the 10-year period. The pattern for suicide was distinctly seasonal: it was above average all spring and below average all winter. For homicides, the pattern was more monthly, with July–September and December being above average times and January–June being below average.

Analysis of data on 106,848 marriages in the cities of Bangalore and Mysore, South India, between 1980 and 1989 showed that levels of consanguineous marriage varied between cities through time and by religion. The average coefficient of inbreeding was higher in Bangalore (F = 0·0339) than in Mysore (F = 0·0203), principally reflecting large-scale, post-Independence rural migration into Bangalore. Although there was some evidence of a decline in consanguineous marriages in Mysore, there was no convincing support in either city for earlier projections of a rapid reduction in the popularity of unions between close biological relatives.

A study of employment during pregnancy and its effects was carried out among pregnant women who were under the care of the Community Health Center, Hadassah Medical School, in a neighbourhood of West Jerusalem. Of the women, 46−2% worked during pregnancy, and 78−6% of them were in occupations which demanded light physical activity. Most of the women worked throughout the whole pregnancy. Educational level as well as parity emerged as the main factors in determining whether a pregnant woman worked or not. No significant effects of employment were found in pregnancy complications or length of gestation, but significant differences did emerge in the number of delivery abnormalities. This finding is interpreted as the result of the interaction of several social conditions rather than of work itself. The findings support the hypothesis that work by itself does not affect either pregnancy or its outcome (as measured by birth weight).

This paper reports the results of a June 1980 survey of 1069 children in Changsha, Hunan Province. The data have been unavailable previously either in Chinese or in English. In general, they suggest that comparisons of single children with children from multiple-child families in China regarding quality of life, intellectual development, and behavioural traits are similar to comparisons conducted in the United States and other western countries. As in many western studies, single children in China appear to have a better quality of life than children with siblings. Regarding intellectual development, single children in China perform better than those with siblings, a finding which is consonant with the family intactness model of Falbo. Single children in Changsha are little different from ones from multiple-child families on various aspects of behaviour, and are more co-operative and less hostile. These findings are the opposite of those of the Shanghai study, the other major analysis of single children in China; the Shanghai survey indicated that single children were not as well-behaved as those with siblings, a finding that caused some concern among Chinese social scientists. To the extent that the findings of the Changsha study, and not those of the Shanghai study, reflect the situation of single children in China, this could mean that the one-child family planning campaign may not be having a negative impact on children's behaviour.

Bangladesh society is profoundly gender stratified, and yet male roles in reproductive health processes have not been rigorously investigated. This study examines the association between men’s reproductive health knowledge, attitude and behaviour and their wives’ subsequent reproductive behaviour using longitudinal data from the International Centre for Diarrhoeal Disease Research, Bangladesh (ICDDR,B). A total of 4969 matched husband-and-wife data from a 1998 survey and women’s contraceptive use history data following this survey are used. Results show a significant association between husbands’ fertility preferences and current use of any family planning method. When wives’ background characteristics, and husbands’ background and socioeconomic characteristics are controlled for, the predicted probability of using a method of contraception among non-educated wives whose husbands want more children is 0·49 compared with 0·64 for those whose husbands do not want more children. However, the net effect of husbands’ preference for additional children diminishes as wives’ level of education increases. Among wives who had completed high school, the predicted probability of using a method of contraception is 0·70 for those whose husbands want more children compared with 0·69 for those whose husbands do not want more children.

Substantial numbers of married women use contraceptives without their partner’s knowledge in sub-Saharan Africa, but studies of female covert use across time are rare. This study investigates the levels, trends and correlates of covert use in nine countries and determines which contraceptive methods are more frequently used covertly by women. Data from monogamous couples in Demographic and Health Surveys were used from nine sub-Saharan African countries that had experienced an increase of 10 percentage points in current modern contraceptive use between an earlier (1991–2004) and later (2007–2011) survey. Covert use was indirectly estimated as the percentage of women who reported a female modern method whose husband did not report a modern method. The percentage of women using covertly increased in eight of the countries studied (significantly in three of them), yet when comparing across countries cross-sectionally, covert use was lower where contraceptive prevalence was higher. In general, women with more years of schooling and those with larger spousal schooling gaps had lower odds of covert use. There was no significant difference between covert and open injectable use, though more than half of both groups used this method in the later surveys. Encouraging couple communication about contraception, where the woman feels it is safe to do so, could be an important strategy to minimize covert use. Further research is needed to better identify the contraceptive prevalence and social context in which covert use declines within a country.

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 relationship between sleep habits and psychosomatic health complaints was investigated by a questionnaire study in 148 bank workers in Tokyo. Daily bedtime was more flexible than daily rising time, and both mean bedtime and rising time tended to be earlier with increasing age. Multiple logistic regression analysis showed that psychosomatic health complaints of sleep disturbances, fatigue, digestive troubles, and depressive mood were significantly associated with sleep habits and perceived mental stress.