Kin and birth order effects on male child mortality: three East Asian populations, 1716–1945

Human child survival depends on adult investment, typically from parents. However, in spite of recent research advances on kin influence and birth order effects on human infant and child mortality, studies that directly examine the interaction of kin context and birth order on sibling differences in child mortality are still rare. Our study supplements this literature with new findings from large-scale individual-level panel data for three East Asian historical populations from northeast China (1789–1909), northeast Japan (1716–1870), and north Taiwan (1906–1945), where preference for sons and first-borns is common. We examine and compare male child mortality risks by presence/absence of co-resident parents, grandparents, and other kin, as well as their interaction effects with birth order. We apply discrete-time event-history analysis on over 172,000 observations of 69,125 boys aged 1–9 years old. We find that in all three populations, while the presence of parents is important for child survival, it is more beneficial to first/early-borns than to later-borns. Effects of other co-resident kin are however null or inconsistent between populations. Our findings underscore the importance of birth order in understanding how differential parental investment may produce child survival differentials between siblings.     

Does the number of sons born affect long-term mortality of parents? A cohort study in rural Bangladesh

It has been suggested that bearing sons increases long-term mortality in women, because sons may be more physiologically demanding to produce than daughters. In this historical cohort study in rural Bangladesh, no association between the number of sons born and mortality was seen in women in the unadjusted analyses. However, a significant reduction in mortality with the number of surviving sons was seen. In addition, after adjusting for the number of surviving sons, there was evidence of increasing mortality with the number of sons born, in women. In men, mortality also depended strongly on the number of surviving sons, but not on the number born. These data provide support for negative long-term costs of bearing sons in mothers in rural Bangladesh, and suggest that there are context-specific factors that mask the true effects of sons in some populations.     

Mortality and age differences in marriage.

Data from the 1971 census population were used to evaluate the effects of age differences of married partners on mortality rates. Different age groups were isolated to highlight the association between mortality and age of spouse for specific ages of married men and women. Men married to much younger or to older women exhibited a higher mortality rate than men married to women who were only a few years younger than themselves. A similar trend was observed among women married to much younger or much older men compared with those whose spouses were a few years older or of similar ages as themselves. Trends for other age groups (women aged 60-69 years, men below 40, and women below 30) did not exhibit a clear pattern. Although statistical biases within age groups may in part account for the differences in the findings, the trend which emerged from the analysis suggests that lower morbidity is associated with the most common age combinations (husbands same age or slightly older than wives). Other factors could also account for the differences (e.g., selection of healthy partners in 1st marriages, differences in lifestyles between married and single).     

Physiological changes in successive pregnancies and birth‐order effects

Abstract

An analysis of mortality rates documents that the well‐established female advantage in mortality continues to increase. Data from the U.S. census show that the sex differential in mortality has increased from 1.69 in 1963 to 1.82 in 1976. The age groups which show the most pronounced changes are youth (15–24), young adults (25–34), and old persons (75–84). Following Enterline (1961), we assess the major causes of death within each of these age groups in terms of their relative contributions to changing sex ratios. The major factors among young persons, apart from declining maternal mortality, are found to involve violent deaths, especially traffic accidents and suicide. Among old persons, death rates in general have declined, but advances in medical technology appear to have been more beneficial for older women than for older men, supporting the hypothesis of a biological superiority among women. However, death rates for malignant neoplasms have increased for older women as well as older men, suggesting that changing life styles may eventually have an impact on female mortality. The data suggest a need for additional research concerning the increase in violent deaths among young women and the potential increase in cancer deaths among older women.     

Gender-related changes in three-dimensional microstructure of trabecular bone at the human proximal tibia with aging

Despite increasing interest in age- and gender-related bone alterations, data on trabecular microstructure at the proximal tibia are scarce. The aim of this study was to identify trabecular microstructural change at the human proximal tibia with age and gender, using micro-computed tomography (micro-CT) and scanning electron microscopy (SEM). Fifty-six proximal tibias from 28 Japanese men and women (57-98 years of age) were used in this study. The subjects were chosen to give an even age and gender distribution. Both women and men were divided into three age groups, middle (57-68 years), old (72-82 years) and elderly (87-98 years) groups. The trabecular bone specimens from the medial compartment of the proximal tibial metaphysis were examined. Trabecular bone mineral density (BMD), bone volume fraction (BV/TV) and trabecular thickness (Tb.Th) decreased between the middle-aged and elderly groups similarly in women and men. However, trabecular number (Tb.N) decreased by 13% between the middle-aged and elderly groups in women and nearly double that in men. As compared with women, men had higher BV/TV and lower trabecular separation (Tb.Sp) in the old age and elderly groups, and higher Tb.N and connectivity density (Conn.D) in the elderly group. Increased trabecular resorbing surfaces, perforated or disconnected trabeculae and microcallus formations were observed with age. These findings indicate that both BMD and BV/TV decreased at the proximal tibia with age similarly for women and men, but significant differences between women and men were observed for some microstructural parameters. These findings illustrate potential mechanisms underlying osteoporotic proximal tibial fracture.     

Low Socioeconomic Status and Female-Biased Parental Investment: The Mukogodo Example

Hierarchies of wealth and ethnic prestige among East African herders present an opportunity to test the Trivers-Willard hypothesis that low socioeconomic status should correlate with female biases in parental investment. The Mukogodo are at the bottom of such a regional hierarchy due to their poverty and low status as former hunters. As a result of these factors, Mukogodo men have lower polygyny rates than their neighbors, and Mukogodo women have higher mean reproductive success than Mukogodo men. The data fulfill the prediction that there should be a bias in parental investment in favor of daughters. The sex ratio of the 0–4 age group and the reported sex ratio at birth are both female-biased. Although there is no evidence of infanticide, sons may be neglected in favor of daughters. Evidence from a dispensary and from a clinic run by a Catholic mission both show that the Mukogodo take daughters for treatment more often than they take sons. Also, daughters may be nursed longer than sons.     

Mortality of bereavement.

The death rate of a group of 87 widowers and 279 widows was followed for two years from the death of their spouses. The life tables for England and Wales 1970-2 indicated that the expected number of deaths would be 6 men and 11 women. The actual numbers (9 men and 11 women, 5.5%) were not significantly different, though there were more widowers'' deaths during the first six months of bereavement. There was no significantly greater mortality among those whose spouses had died in hospital; but when this had occurred the health of the second spouse was likely to have been poorer than that of those whose spouses had died at home.     

Who suppresses female sexuality? An examination of support for Islamic veiling in a secular Muslim democracy as a function of sex and offspring sex

Whether it is men or women who suppress female sexuality has important implications for understanding gendered relations, ultimately providing insight into one widespread cause of female disadvantage. The question of which sex suppresses female sexuality more avidly, however, neglects that our interests are never unambiguously masculine or feminine; each of us has a combination of male and female kin which alters how much of our future fitness derive from each sex. Here we exploit a nationally representative sample of 600 Tunisians to test whether support for Islamic veiling—a proxy for female sexual suppression—is more common amongst one sex than the other, and is affected by the relative sex of one's offspring (i.e., the number of sons relative to daughters). We find that men are more supportive of Islamic veiling than women, but women with more sons are more supportive of veiling and more likely to wear veils than women with fewer sons. All effects were robust to the inclusion of religiosity, which was weaker amongst men and unrelated to the number of sons a woman had. The number of daughters affected neither religiosity nor support for veiling, but did increase women's likelihood of wearing contemporary, fashionable Tunisian veils compared with no head covering. We further found that men were more religious if they had more sons. Overall, these findings highlight that far from being the fixed strategy of one sex or the other, female sexual suppression manifests facultatively to promote one's reproductive interests directly or indirectly by creating conditions beneficial to one's descendent kin. These results show that both men and women can suppress female sexuality, although the function in either case appears more closely aligned with male rather than female interests.     

Effects of age and regular exercise on muscle strength and endurance

Twenty male and 20 female non-professional tennis players were classified into two different age groups (n = 10 per group): young active men (30.4 +/- 3.3 years), young active women (27.5 +/- 4.3 years), elderly active men (64.4 +/- 3.7 years), and elderly active women (65.3 +/- 4.5 years). These individuals were matched (n = 10 per group) according to sex, age, height and mass to sedentary individuals of the same socio-economical background: young sedentary men (29.2 +/- 3.4 years), young sedentary women (25.6 +/- 4.4 years), elderly sedentary men (65.2 +/- 3.2 years) and elderly sedentary women (65.6 +/- 4.4 years). An isokinetic dynamometer was used to measure the strength of the knee extensors and flexors (two separate occasions) and the endurance of the extensors. Vastus lateralis electromyogram (EMG) was measured concomitantly. Significant sex, age and exercise effects (P less than 0.001) were observed for peak torque of both muscle groups. The effect of age on extensor strength was more pronounced at high speeds where men were also able to generate larger relative torques than women. No age or sex effects were noted for muscle endurance. However, muscles of active individuals demonstrated a greater resistance to fatigue than those of sedentary individuals. In conclusion, men were found to be stronger than women, age was associated with a decrease in muscle strength, but not of muscle endurance, and tennis players were stronger and had muscles that were more resistant to fatigue than their sedentary pairs in both age groups.(ABSTRACT TRUNCATED AT 250 WORDS)     

Outlook for survivors of childhood in sub-Saharan Africa: adult mortality in Tanzania. Adult Morbidity and Mortality Project.

OBJECTIVE--To measure age and sex specific mortality in adults (15-59 years) in one urban and two rural areas of Tanzania. DESIGN--Reporting of all deaths occurring between 1 June 1992 and 31 May 1995. SETTING--Eight branches in Dar es Salaam (Tanzania''s largest city), 59 villages in Morogoro rural district (a poor rural area), and 47 villages in Hai district (a more prosperous rural area). SUBJECTS--40,304 adults in Dar es Salaam, 69,964 in Hai, 50,465 in Morogoro rural. MAIN OUTCOME MEASURES--Mortality and probability of death between 15 and 59 years of age (45Q15). RESULTS--During the three year observation period a total of 4929 deaths were recorded in adults aged 15-59 years in all areas. Crude mortalities ranged from 6.1/1000/year for women in Hai to 15.9/1000/year for men in Morogoro rural. Age specific mortalities were up to 43 times higher than rates in England and Wales. Rates were higher in men at all ages in the two rural areas except in the age group 25 to 29 years in Hai and 20 to 34 years in Morogoro rural. In Dar es Salaam rates in men were higher only in the 40 to 59 year age group. The probability of death before age 60 of a 15 year old man (45Q15) was 47% in Dar es Salaam, 37% in Hai, and 58% in Morogoro; for women these figures were 45%, 26%, and 48%, respectively. (The average 45Q15s for men and women in established market economies are 15% and 7%, respectively.) CONCLUSION--Survivors of childhood in Tanzania continue to show high rates of mortality throughout adult life. As the health of adults is essential for the wellbeing of young and old there is an urgent need to develop policies that deal with the causes of adult mortality.     

Measuring Adult Mortality Using Sibling Survival: A New Analytical Method and New Results for 44 Countries, 1974–2006

Background

For several decades, global public health efforts have focused on the development and application of disease control programs to improve child survival in developing populations. The need to reliably monitor the impact of such intervention programs in countries has led to significant advances in demographic methods and data sources, particularly with large-scale, cross-national survey programs such as the Demographic and Health Surveys (DHS). Although no comparable effort has been undertaken for adult mortality, the availability of large datasets with information on adult survival from censuses and household surveys offers an important opportunity to dramatically improve our knowledge about levels and trends in adult mortality in countries without good vital registration. To date, attempts to measure adult mortality from questions in censuses and surveys have generally led to implausibly low levels of adult mortality owing to biases inherent in survey data such as survival and recall bias. Recent methodological developments and the increasing availability of large surveys with information on sibling survival suggest that it may well be timely to reassess the pessimism that has prevailed around the use of sibling histories to measure adult mortality.

Methods and Findings

We present the Corrected Sibling Survival (CSS) method, which addresses both the survival and recall biases that have plagued the use of survey data to estimate adult mortality. Using logistic regression, our method directly estimates the probability of dying in a given country, by age, sex, and time period from sibling history data. The logistic regression framework borrows strength across surveys and time periods for the estimation of the age patterns of mortality, and facilitates the implementation of solutions for the underrepresentation of high-mortality families and recall bias. We apply the method to generate estimates of and trends in adult mortality, using the summary measure ₄₅ q ₁₅—the probability of a 15-y old dying before his or her 60th birthday—for 44 countries with DHS sibling survival data. Our findings suggest that levels of adult mortality prevailing in many developing countries are substantially higher than previously suggested by other analyses of sibling history data. Generally, our estimates show the risk of adult death between ages 15 and 60 y to be about 20%–35% for females and 25%–45% for males in sub-Saharan African populations largely unaffected by HIV. In countries of Southern Africa, where the HIV epidemic has been most pronounced, as many as eight out of ten men alive at age 15 y will be dead by age 60, as will six out of ten women. Adult mortality levels in populations of Asia and Latin America are generally lower than in Africa, particularly for women. The exceptions are Haiti and Cambodia, where mortality risks are comparable to many countries in Africa. In all other countries with data, the probability of dying between ages 15 and 60 y was typically around 10% for women and 20% for men, not much higher than the levels prevailing in several more developed countries.

Conclusions

Our results represent an expansion of direct knowledge of levels and trends in adult mortality in the developing world. The CSS method provides grounds for renewed optimism in collecting sibling survival data. We suggest that all nationally representative survey programs with adequate sample size ought to implement this critical module for tracking adult mortality in order to more reliably understand the levels and patterns of adult mortality, and how they are changing. Please see later in the article for the Editors'' Summary     

Activity pattern, smoking habits, and somatometric variables of the Czechoslovakian population

A total of 3762 subjects of both sexes, natives of Czechoslovakia, ranging in age from 12--55 years, were examined. Both anamnestic data and selected anthropometric variables were evaluated. The proportion of non-smokers for adult males was 47--56%, and for adult females was 54--74% of the population. The proportion of subjects not engaged in any type of physical activity decreases in boys between 12 and 18 years from 28 to 16%, in girls between 12 and 15 years from 25 to 22%; from then on the trend reverses and the percentages rises up to 42% in men and 65% in women. The number of subjects participating in competitive sporting activity reaches its peak at 18 years, when 46% of boys annd 43% of girls compete, but then decreases quickly. 12 year old girls are taller and heavier than boys but at 15 years the relationship is reversed. The LBM at the age of 12 is equal in boys and girls, but from then till 18 years the increase is larger in boys. The LBM weight in adults remains steady, women attaining 77% of the value found in men. The skinfold increases with age similarly in both sexes, except for an interval between 12 and 18 years, when girls show a steeper increase. Adult women attain 121--160% of the values characteristic for men. The grip strength of the right hand equals about 50 kp in adult men and 30 kp in adult women. Within the age range followed, it remains unaffected by age.     

Age Differences Between Spouses in a Brazilian Marriage Sample

Age differences between spouses were investigated in a Brazilian marriage sample. A study was made of 3,000 announcements of forthcoming marriages sampled from the newspaper Diario de Noticias de São Paulo, in September and October 1996. These announcements published in newspapers are a legal requirement for marriage. Men married women younger than themselves, and this tendency became more pronounced over the lifespan. There was only one exception: young men <20 years old married older partners. Young women married men older than themselves, but this tendency became less pronounced over the lifespan. Age differences between spouses violate the similarity-attraction rule, one of the strongest general principles of mate selection, but fit well with an evolutionary model.     

Intrinsic glands of the adult human esophagus

In 114 esophagi of men and women in mature, elderly and old age, the number, distribution density, size of the secretory parts in the proper glands and area of the ostia of their ducts in various parts of the organ have been studied macro-microscopically with subsequent morphometry. With transition from mature to elderly and old age, their number and distribution density increase. There is no differences revealed in total number of the glands between men and women. In the men in the middle third of the esophagus the number of the glands is greater than in its upper and lower parts. In old age length and width of the glandular secretory parts in the lower third of the esophagus and their length in the middle part of the organ decrease. Dimensions of the glandular secretory parts increase in the craniocaudal direction.     

Vitamin E ingestion improves several immune functions in elderly men and women

The effects of diet supplementation with the antioxidant vitamin E (200 mg daily) on several blood neutrophil, lymphocyte and natural killer cell functions have been investigated in healthy elderly men and women before supplementation, after 3 months of supplementation and 6 months after the end of supplementation (post-supplementation). In parallel, samples of healthy adult men and women were used as age controls. In elderly men and women, an impairment of immune functions was observed in comparison with the respective adult controls and the intake of vitamin E resulted in a significant enhancement of immune parameters in both elderly men and women, bringing their values close to those in the adults. These effects were not found in post-supplementation samples in several but not in all functions. The present findings suggest that supplementation with vitamin E can produce an improvement of immune functions and therefore of health in aged people.     

Vitamin E ingestion improves several immune functions in elderly men and women

The effects of diet supplementation with the antioxidant vitamin E (200 mg daily) on several blood neutrophil, lymphocyte and natural killer cell functions have been investigated in healthy elderly men and women before supplementation, after 3 months of supplementation and 6 months after the end of supplementation (post-supplementation). In parallel, samples of healthy adult men and women were used as age controls. In elderly men and women, an impairment of immune functions was observed in comparison with the respective adult controls and the intake of vitamin E resulted in a significant enhancement of immune parameters in both elderly men and women, bringing their values close to those in the adults. These effects were not found in post-supplementation samples in several but not in all functions. The present findings suggest that supplementation with vitamin E can produce an improvement of immune functions and therefore of health in aged people.     

The Unchanging Pattern of Pulmonary Tuberculosis

Study of mortality from pulmonary tuberculosis in Ontario between 1881 and 1961 reveals a steady decline in rates since the beginning of this century, affecting both sexes and all age groups. This decline has been much faster in the younger than in the older age groups. When the mortality rates are studied for groups of men and women born within 10-year periods (10-year cohorts) an orderly pattern of mortality emerges, consisting of two distinct phenomena. First, the shape of the “cohort” curves is always similar: the mortality rates rise sharply in childhood and the peak is reached in early adult life, followed by a gradual descent. This appears to be a basic but unexplained feature of pulmonary tuberculosis. Secondly, each cohort shows through its life span a lower mortality rate than the previous cohort, but a higher rate than the succeeding one; it is suggested that this is primarily due to a decline in intensity of tuberculous infection over the past several decades. The high tuberculosis rates seen now in the elderly are but the residue of the much higher rates experienced by these people early in their lives.     

The CroHort study: cardiovascular behavioral risk factors in adults, school children and adolescents, hospitalized coronary heart disease patients, and cardio rehabilitation groups in Croatia

Based on repeated measurement of health behaviors the CroHort Study showed that health behavior explains a great deal more of class inequalities in mortality than observed in previous studies. These include decreasing prevalence of smoking and increase in obesity, hypertension and diabetes mellitus. The lowest prevalence of health risks was recorded among children and adolescents, followed by general adult population from the CroHort Study. Hospitalized coronary heart disease patients had higher risks prevalence than general population, while the highest prevalence of risks was recorded among patients in cardiac rehabilitation program. The higher levels of stress were associated to lower financial conditions, poorer social functioning and poorer mental health for both men and women. Higher levels of stress were also associated with heart problems, higher alcohol consumption in men while in women stress was associated to poorer general health, higher age and lower levels of education.     

Median age at death as an indicator of premature mortality

The median age at death from certain diseases was calculated for each year for 1969-85 and compared with that at death from all causes. The results indicated the impact of these diseases in terms of premature mortality and changes over time. Cancer was a more important cause of premature mortality among women than among men. For cancer of the cervix the median age at death increased appreciably whereas for cancer of the lung in women it slightly decreased. The median age at death is easy to calculate, does not require standardisation, and has a useful role.     

Marrying women 15 years younger maximized men's evolutionary fitness in historical Sami

Most men marry younger women. This has been attributed to men selecting young women due to their high reproductive value and women preferring older men due to their wealth and high social status. Such mate preferences have been suggested to be adaptive, but despite a flourishing number of studies on the mate selection patterns themselves, little is still known of their actual fitness consequences. We examined how the age difference between spouses who married only once affected their lifetime reproductive success in historical monogamous Sami populations. We found that men maximized their fitness by marrying women approximately 15 years younger and vice versa. However, most couples failed to marry optimally. Only 10% of marriages fell within the optimal parental age difference, suggesting that cultural and ecological constraints for maximizing fitness were considerable. Those who succeeded in marrying optimally were the most preferred partners: young women and old men. Our findings indicate that, in Sami, parental age difference was under natural and sexual selection, as suggested by evolutionary theory.