Sex differences in human mortality: the role of genetic factors

Female sex bias in Iberian megalithic societies through bioarchaeology, aDNA and proteomics

Uncertainties regarding traditional osteological methods in biological sex estimation can often be overcome with genomic and proteomic analyses. The combination of the three methodologies has been used for a better understanding of the gender-related funerary rituals at the Iberian megalithic cemetery of Panoría. As a result, 44 individuals have been sexed including, for the first time, non-adults. Contrary to the male bias found in many Iberian and European megalithic monuments, the Panoría population shows a clear sex ratio imbalance in favour of females, with twice as many females as males. Furthermore, this imbalance is found regardless of the criterion considered: sex ratio by tomb, chronological period, method of sex estimation, or age group. Biological relatedness was considered as possible sociocultural explanations for this female-related bias. However, the current results obtained for Panoría are indicative of a female-centred social structure potentially influencing rites and cultural traditions.

Mortality risk in infants receiving therapeutic care for malnutrition: A secondary analysis

Small and nutritionally at-risk infants aged under 6 months (<6 months) are at high risk of death, but important evidence gaps exist on how to best identify them. We aimed to determine associations between anthropometric deficits and mortality among infants <6 months admitted to inpatient therapeutic care. A secondary analysis of 2002-2008 data included 5034 infants aged <6 months from 12 countries. We estimated the prevalence, concurrence, and severity of wasted, stunted, and underweight, as stand-alone indicators, and using the Composite Index of Anthropometric Failure (CIAF), which combines these indicators into six subgroups of single and multiple anthropometric deficits and into one combined indicator called CIAF. We used logistic regression to examine the association of different anthropometric deficits with in-programme mortality. Among 3692 infants aged <6 months with complete data, 3539 (95.8%) were underweight, 3058 (82.8%) were wasted, 2875 (77.8%) were stunted and 3575 (96.8%) had CIAF. Infants with multiple anthropometric deficits were presented with significantly lower anthropometric indices, that is, they were more severely wasted, stunted and underweight. A total of 141 infants died during inpatient therapeutic care. Among these, severely wasted (116) and severely underweight (138) infants had higher odds of mortality than normal infants (odds ratio [OR] = 2.1, 95% confidence interval [CI]: 1.2-2.7, p = 0.009, and OR = 3.3, 95% CI: 0.8-13.6, p = 0.09, respectively). Boys had higher odds of inpatient mortality than girls (OR = 1.40, 95% CI: 1.02-1.92, p = 0.03). Mortality was only observed in infants <6 months presenting multiple anthropometric deficits, although their odds of mortality were not significant, for example, OR = 2.4, 95% CI: 0.5-10.0, p = 0.21 for stunted, wasted and underweight infants <6 months. In conclusion, multiple anthropometric deficits (CIAF) is common among infants <6 months and may be reported in nutrition care programmes and surveys. Both weight-for-length/height z-score and weight-for-age z-score were found to be useful indicators for programme admission and in-programme prognosis. Future work needs to explore which better accounts for admission bias. Boys appear to be most at-risk of dying while receiving malnutrition therapeutic care. Programmes should ensure that all infants receive timely, evidence-based, effective care.

Complex Sex Differences in Life Expectancy in French Guiana

In the complex context of French Guiana, different vulnerabilities and different risk factors between genders may lead to complex differences in health outcomes, mortality, and life expectancy. Our aim was, thus, to compare male and female mortality and life expectancy, to compare it between French Guiana and mainland France, and to look at temporal trends and the main specific causes of death in order to identify actionable singularities. National databases were used to obtain life expectancy at birth, at 20, 40, and 60 years, and mortality statistics. Standardized death rates and causes of death for French Guiana and mainland France were obtained through the CEPIDC, which analyzes information from death certificates. When comparing with mainland France, life expectancy at birth was significantly shorter both in males and females (mean = -2.9 years); life expectancy at 20 years, which allows to remove the effect of the greater child mortality in French Guiana, was also shorter in French Guiana for males (mean = -1.8 years) and females (mean = -2 years). The differences between mainland France and French Guiana regarding life expectancy at 40 and 60 years (mean = -1.5 and -1.3 years) was mainly found among females, males in French Guiana life expectancy at 40 and 60 years was closer to that in mainland France (mean = -0.8 and -0.6 years). Although they have a greater life expectancy at birth than men, women in French Guiana are substantially more affected by overweight/obesity and type 2 diabetes. The observed patterns of life expectancy at different ages presumably reflect the burden of external causes and AIDS in males and perhaps metabolic diseases in women.

Girls unwanted - The role of parents' child-specific sex preference for children's early mental development

We propose a novel son preference measure that relates the preference to a specific child. We find child-specific son preference to be more common among later born children and in families with fewer sons. Using the novel measure and an interaction instrumental variables approach, we estimate a penalty in early mental functions for unwanted girls of 0.7 standard deviations. This penalty appears to be partially driven by discrimination against girls and partially by pampering of boys. Children's health and parental inputs do not mediate the effect from son preference to mental development. Our findings highlight the relevance of parents' attitudes for a nurturing home environment and healthy brain development.

Sex inequality in under-five deaths and associated factors in low and middle-income countries: a Fairlie decomposition analysis

Background

There exist sex disparities in the burden of Under-five deaths (U5D) with a higher prevalence among male children. Factors explaining this inequality remain unexplored in Low-and Medium-Income Countries (LMIC). This study quantified the contributions of the individual- and neighborhood-level factors to sex inequalities in U5D in LMIC.

Methods

Demographic and Health Survey datasets (2010-2018) of 856,987 under-five children nested in 66,495 neighborhoods across 59 LMIC were analyzed. The outcome variable was U5D. The main group variable was the sex of the child while individual-level and neighborhood-level factors were the explanatory variables. Fairlie decomposition analysis was used to quantify the contributions of explanatory factors to the male-female inequalities in U5D at p<0.05.

Results

Overall weighted prevalence of U5D was 51/1000 children, 55 among males and 48 among females (p<0.001). Higher prevalence of U5D was recorded among male children in all countries except Liberia, Kyrgyz Republic, Bangladesh, Nepal, Armenia, Turkey and Papua New Guinea. Pro-female inequality was however not significant in any country. Of the 59 countries, 25 had statistically significant pro-male inequality. Different factors contributed to the sex inequality in U5D in different countries including birth order, birth weight, birth interval and multiple births.

Conclusions

There were sex inequalities in the U5D in LMIC with prominent pro-male-inequality in many countries. Interventions targeted towards the improvement of the health system that will, in turn, prevent preterm delivery and improve management of prematurity and early childhood infection (which are selective threats to the male child survival) are urgently required to address this inequality.

The Causes of Death and Their Influence in Life Expectancy of Children Aged 5-14 Years in Low- and Middle-Income Countries From 1990 to 2019

INTRODUCTION

Although child and adolescent health is the core of the global health agenda, the cause of death and its expected contribution to life expectancy (LE) among those aged 5-14 are under-researched across countries, especially in low- and middle-income countries (LMICs).

METHODS

Death rates per 10 years age group including a 5-14-year-old group were calculated by the formula, which used the population and the number of deaths segmented by the cause of death and gender from the 2019 Global Burden of Disease (GBD) study. LE and cause-eliminated LE in 10-year intervals were calculated by using life tables.

RESULTS

In 2019, the global mortality rate for children and adolescents aged 5-14 years was 0.522 (0.476-0.575) per 1,000, and its LF was 71.377 years. In different-income regions, considerable heterogeneity remains in the ranking of cause of death aged 5-14 years. The top three causes of death in low-income countries (LICs) are enteric infections [0.141 (0.098-0.201) per 1,000], other infectious diseases [0.103 (0.073-0.148) per 1,000], and neglected tropical diseases and malaria [0.102 (0.054-0.172) per 1,000]. Eliminating these mortality rates can increase the life expectancy of the 5-14 age group by 0.085, 0.062, and 0.061 years, respectively. The top three causes of death in upper-middle income countries (upper MICs) are unintentional injuries [0.066 (0.061-0.072) per 1,000], neoplasm [0.046 (0.041-0.050) per 1,000], and transport injuries [0.045 (0.041-0.049) per 1,000]. Eliminating these mortality rates can increase the life expectancy of the 5-14 age group by 0.045, 0.031, and 0.030 years, respectively.

CONCLUSION

The mortality rate for children and adolescents aged 5-14 years among LMICs remains high. Considerable heterogeneity was observed in the main causes of death among regions. According to the main causes of death at 5-14 years old in different regions and countries at different economic levels, governments should put their priority in tailoring their own strategies to decrease preventable mortality.

Levels and potential drivers of under-five mortality sex ratios in low- and middle-income countries

BACKGROUND

Non-biological childhood mortality sex ratios may reflect community sex preferences and gender discrimination in health care.

OBJECTIVE

We assessed the association between contextual factors and gender bias in under-five mortality rates (U5MR) in low- and middle-income countries.

METHODS

Full birth histories available from Demographic and Health Surveys and Multiple Indicator Cluster Surveys (2010-2018) in 80 countries were used to estimate U5MR male-to-female sex ratios. Expected sex ratios and their residuals (difference of observed and expected) were derived from a linear regression model, adjusted for overall mortality. Negative residuals indicate more likelihood of discrimination against girls, and we refer to this as a measure of potential gender bias. Associations between residuals and national development and gender inequality indices and with survey-derived child health care indicators were tested using Spearman's correlation.

RESULTS

Mortality residuals for under-five mortality were not associated with national development, education, religion, or gender inequality indices. Negative residuals were more common in countries where boys were more likely to be taken to health services than girls (rho -0.24, 95% confidence interval -0.45, -0.01).

CONCLUSIONS

Countries where girls were more likely to die than boys, accounting for overall mortality levels, were also countries where boys were more likely to receive health care than girls. Further research is needed to understand which national characteristics explain the presence of gender bias, given that the analyses of development levels and gender equality did not discriminate between countries with or without excess mortality of girls. Reporting on child mortality separately by sex is required to enable such advances.

Socioeconomic, urban-rural and sex-based inequality in infant mortality rate: evidence from 2013 Yemen demographic and health survey

Background

The occurrence of Infant Mortality Rate (IMR) varied globally with most of the cases coming from developing countries including Yemen. The disparity in IMR in Yemen however, has not been well dealt and therefore we examined the IMR inequality based on the most reliable methodology in order to generate evidence-based information for some program initiatives in Yemen.

Methods

Based on the World Health Organization (WHO) Health Equity Assessment Toolkit (HEAT) software, we analyzed the inequality across the different inequality dimensions in Yemen. The toolkit analyzes data stored in the WHO health equity monitor database. Simple and complex, and absolute and relative measures of inequality were calculated for the four dimensions of inequality (subpopulations) which included wealth, education, sex and residence. We computed a 95 % CI to assess statistical significance.

Results

The analysis included 31, 743 infants. Absolute and relative wealth-driven, education, urban-rural and sex-based inequalities were found in IMR. Higher concentration of IMR was observed among infants from the poorest/poor households (ACI=-4.68, 95 % CI; -6.57, -2.79, R = 1.61, 95 % CI; 1.18, 2.03), rural residents (D = 15.07, 95 % CI; 8.04, 22.09, PAF=-23.57, 95 % CI; -25.47, -21.68), mothers who had no formal education (ACI=-2.16, 95 % CI; -3.79, -0.54) and had male infants (PAF= -3.66, 95 % CI; -4.86, -2.45).

Conclusions

Higher concentration of IMR was observed among male infants from disadvantaged subpopulations such as poorest/poor, uneducated and rural residents. To eliminate the observed inequalities, interventions are needed to target the poorest/poor households, rural residents, mothers with no formal education and male infants.

Medical mortality in an emergency department in Nigeria: the transition is obvious!

Introduction

The emergency department (ED), a major entry point into the hospital, provides an insight to the type of cases seen, the quality of care and mortality spectrum in a health institution. We aim to identify the spectrum of medical causes of mortality in our ED, the demographic pattern and duration of stay before death.

Method

This is a retrospective study that looked at medical mortality in the ED from January 2004 to December 2009. We obtained data on the demographics and causes of death from the medical records and case notes of the deceased.

Results

A total of 16587 patients were admitted during the period under review, of these 1262 (7.61%) died in the ED. The male to female ratio was 1.58:1.0 [772 males (61.2%), and 489 females (38.8%)]. Mortality was highest among the 20–45 years age range, followed by 46–65 years, >65 years and < 20 years in decreasing frequency [589(46.7%), 421(33.4%), 186 (14.8%) and 66(5.2%) respectively]. The three most common causes of death were stroke 315(25%), HIV related illnesses 126(10.0%), and heart failure 123(9.7%). Most deaths occurred less than 24hours of admission, 550(43.6%), followed by one day (36.0%) and two days (10.8%) post admissions respectively.

Conclusion

The commonest cause of death in the ED was stroke. The burden of death was highest in the younger age group, with most occurring less than 24 hours of admission.

Household factors and under-five mortality in Bankass, Mali: results from a cross-sectional survey

BACKGROUND

Rural parts of Mali carry a disproportionate burden of the country's high under-five mortality rate. A range of household factors are associated with poor under-five health in resource-limited settings. However, it is unknown which most influence the under-five mortality rate in rural Mali. We aimed to describe household factors associated with under-five mortality in Bankass, a remote region in central Mali.

METHODS

We analysed baseline household survey data from a trial being conducted in Bankass. The survey was administered to households between December 2016 and January 2017. Under-five deaths in the five years prior to baseline were documented along with detailed information on household factors and women's birth histories. Factors associated with under-five mortality were analysed using Cox regression.

RESULTS

Our study population comprised of 17,408 under-five children from 8322 households. In the five years prior to baseline, the under-five mortality rate was 152.6 per 1000 live births (158.8 and 146.0 per 1000 live births for males and females, respectively). Living a greater distance from a primary health center was associated with a higher probability of under-five mortality for both males (adjusted hazard ratio [aHR] 1.53 for ≥10 km versus < 2 km, 95% confidence interval [CI] 1.25-1.88) and females (aHR 1.59 for ≥10 km versus < 2 km, 95% CI 1.27-1.99). Under-five male mortality was additionally associated with lower household wealth quintile (aHR 1.47 for poorest versus wealthiest, 95%CI 1.21-1.78), lower reading ability among women of reproductive age in the household (aHR 1.73 for cannot read versus can read, 95%CI 1.04-2.86), and living in a household with access to electricity (aHR 1.16 for access versus no access, 95%CI 1.00-1.34).

CONCLUSIONS

U5 mortality is very high in Bankass and is associated with living a greater distance from healthcare and several other household factors that may be amenable to intervention or facilitate program targeting.

When children have children: The effects of child marriages and teenage pregnancies on early childhood mortality in Bangladesh

This paper examines the adverse effects of adolescent childbearing on early childhood mortality in Bangladesh in mother-fixed-effects regressions using individual mortality outcomes of 300,000 children. Children born to young mothers (child brides in Bangladesh) suffer from higher mortality in the first year of life than their siblings born later. The survival chances of children born to mothers aged 15-49 years are 48-81 % higher in infant period as compared to their siblings born in mother's early adolescence (10-14 years). In poor households, these survival effects extend up to the fifth birthday, especially in the poorest households or among uneducated mothers. This evidence points towards a biological channel, probably low birth weight, as the main contributing factor in the first year of life. In the post-infant period, favorable socio-economic factors (wealth, education) seem to compensate the biological disadvantage of adolescent births. Adolescent pregnancies lead annually to estimated 18,700 under-5 deaths in Bangladesh.

Male survival advantage on the Baja California peninsula

A consistent finding from contemporary Western societies is that women outlive men. However, what is unclear is whether sex differences in survival are constant across varying socio-ecological conditions. We test the universality of the female survival advantage with mortality data from a nineteenth century population in the Baja California peninsula of Mexico. When examined simply, we find evidence for a male-biased survival advantage. However, results from Cox regression clearly show the importance of age intervals for variable survival patterns by sex. Our key findings are that males: (i) experience significantly lower mortality risk than females during the ages 15-30 (RR = 0.69), (ii) are at a significantly increased risk of dying in the 61+ category (RR = 1.30) and (iii) do not experience significantly different mortality risk at any other age interval (0-14, 31-45, 46-60). We interpret our results to stem from differing intrinsic and extrinsic risk factors for sex-biased mortality across age intervals, highlighting the relevance of a lifecourse approach to the study of survival advantage. Ultimately, our results make clear the need to more broadly consider variability in mortality risk factors across time and place to allow for a clearer understanding of human survival differences.

Social inequality in infant mortality in Angola: Evidence from a population based study

INTRODUCTION

Within country inequality in infant mortality poses a big challenge for countries moving towards the internationally agreed upon targets on child mortality by 2030. There is a lack of high-quality evidence on infant mortality measured through different dimensions of social inequality in Angola. Thus, this paper was carried out to address the knowledge gap by conducting in-depth examination of infant mortality rate (IMR) inequality among population subgroups to provide more nuanced evidence to help end IMR disparity in the country.

METHODS

The World Health Organization's (WHO) Health Equity Assessment Toolkit (HEAT) was used to analyze IMR inequality. HEAT is a software application that facilitates examination of disparities in reproductive, maternal, neonatal and child health indicators using the WHO Health Equity Monitor (HEM) database. Inequality of IMR was analyzed through disaggregation by five equity stratifiers: education, wealth, gender, subnational region and residence. These were analyzed through three inequality measures: Population Attributable Risk, Ratio and Slope Index of Inequality. A 95% confidence Interval (CI) was built around point estimates to determine statistical significance.

RESULTS

A notable disadvantage was found for children born to poor (Population Attributable Risk (PAR): -27.0; -28.4, -26.0) and uneducated (PAR: -17.0; -17.9, -16.0), women who live in rural areas (PAR: -7.3;-7.8, -6.7) and those residing in certain regions of the country (PAR: -43.0; 45.3, -4). Male infants had a higher risk of death than female infants (PAR: -6.8;-7.5, -6.2). The subnational regional variation of IMR had been the most evident when compared with the disparities in the other equity stratifers.

CONCLUSIONS

Policymakers and planners need to address the disproportionately higher clustering of IMR among infants born to disadvantaged subpopulations through interventions that benefit such subgroups.

Transition of Son Preference: Evidence From South Korea

Sex ratio at birth remains highly skewed in many Asian countries because of son preference. The ratio in South Korea, however, declined beginning in 1990 and reached the natural range in 2007. We study changes in child gender effects on fertility and parental investment during this period of decreasing sex ratio at birth. We find that gender discrimination on the extensive margin (fertility), such as sex-selective abortions and son-biased stopping rules, have nearly disappeared among recent cohorts. On the intensive margin (parental inputs), boys receive higher expenditures on private academic education, have mothers with fewer hours of labor supply, and spend less time on household chores relative to girls. These gender gaps have also narrowed substantially, however, over the past two decades. We consider alternative explanations, but altogether, evidence suggests the weakening of son preference in South Korea.

Sex Differences in Factors Affecting Hospital Outpatient Department Visits: Korea Health Panel Survey Data from 2009 to 2016

This study intends to inspect the sex differences in proportion of hospital outpatient department (OPD) visits in overall outpatient (OP) visits using national panel data and to explore factors that influence the proportions by sex. This study analyzed data of the 2009–2016 Korea Health Panel Survey. Fractional logit regression was applied to analyze factors that affect proportion of hospital visits among outpatient visits. Analysis of related factors was carried out first for all analysis subjects and then by sex. The study data were provided by 7470 women (52.2%) and 6846 men (47.8%). The overall average number of OP visits was 13.0, and women showed a much higher frequency of visits (15.8) than men (9.9). The average proportion of hospital OPD visits among overall OP visits was 21.9%, and men showed a higher rate (25.1%) than women (19.5%). The analysis model including sociodemographic factors, economic factors, and health-related factors confirmed that men showed a higher rate of hospital usage than women. Type of medical security, household income, participation in economic activities, disability, and serious illnesses were significant variables for both sexes. Age, education level, marital status, and subscription to voluntary private health insurance were significant only for women, whereas region of residence was significant only for men. This study confirmed that there is a sex difference in proportion of hospital OPD visits and in the factors that affect the proportion of hospital OPD visits. Universal health coverage is provided through social health insurance, but there is a sex difference in hospital OPD visits, and factors related to socioeconomic status have a significant effect, especially on women’s selection of health care institutions. More attention should be given to sex differences in factors affecting health care utilization.

The Mechanism Underlying Change in the Sex Gap in Life Expectancy at Birth: An Extended Decomposition

The relationship between differential mortality rates and differences in life expectancy is well understood, but how changing differential rates translate into changing differences in life expectancy has not been fully explained. To elucidate the mechanism involved, this study extends existing decomposition methods. The extended method decomposes change in the sex gap in life expectancy at birth into three components capturing the effects of the sex difference in mortality improvement (ρ-effect), life table deaths density by age (f-effect), and remaining life expectancy by age (e-effect). These three effects oppose and augment each other, depending on relative change in sex-differential mortality rates. The new method is applied to period data for 35 countries and cohort data for 25 countries. The results demonstrate how the mechanism, involving the three effects, operates to determine change in the sex difference in life expectancy. We observe the pivotal importance of the f-effect, which is predominantly negative because of lower female mortality, in favoring narrowing rather than widening of the sex gap, in shifting the overall effect to younger ages, and in exaggerating fluctuations due to crisis mortality. The new decomposition provides a more detailed basis for substantive analyses examining change in differences in life expectancy.

Association between fetal sex, birthweight percentile and adverse pregnancy outcome

Introduction

The objective was to evaluate the association between fetal sex and adverse pregnancy outcome, while correcting for fetal growth and gestational age at delivery.

Material and methods

Data from the Netherlands Perinatal Registry (1999‐2010) were used. The study population comprised all white European women with a singleton delivery between 25⁺⁰ and 42⁺⁶ weeks of gestation. Fetuses with structural or chromosomal abnormalities were excluded. Outcomes were antepartum death, intrapartum/neonatal death (from onset of labor until 28 days after birth), perinatal death (antepartum death or intrapartum/neonatal death), a composite of neonatal morbidity (including infant respiratory distress syndrome, sepsis, necrotizing enterocolitis, meconium aspiration, persistent pulmonary hypertension of the newborn, periventricular leukomalacia, Apgar score <7 at 5 minutes, and intracranial hemorrhage) and a composite adverse neonatal outcome (perinatal death or neonatal morbidity). Outcomes were expressed stratified by birthweight percentile (<p10 [small for gestation], p10‐90 [normal weight], >p90 [large for gestation]) and gestational age at delivery (25⁺⁰‐27⁺⁶, 28⁺⁰‐31⁺⁶, 32⁺⁰‐36⁺⁶, 37⁺⁰‐42⁺⁶ weeks). The association between fetal sex and outcome was assessed using the fetus at risk approach.

Results

We studied 1 742 831 pregnant women. We found no increased risk of antepartum, intrapartum/neonatal and perinatal death in normal weight and large‐for‐gestation males born after 28⁺⁰ weeks compared with females. We found an increased risk of antepartum death among small‐for‐gestation males born after 28⁺⁰ weeks (relative risk [RR] 1.16‐1.40). All males born after 32⁺⁰ weeks of gestation suffered more neonatal morbidity than females regardless of birthweight percentile (RR 1.07‐1.34). Infant respiratory distress syndrome, sepsis, persistent pulmonary hypertension of the newborn, Apgar score <7 at 5 minutes, and intracranial hemorrhage all occurred more often in males than in females.

Conclusions

Small‐for‐gestation males have an increased risk of antepartum death and all males born after 32⁺⁰ weeks of gestation have an increased risk of neonatal morbidity compared with females. In contrast to findings in previous studies we found no increased risk of antepartum, intrapartum/neonatal or perinatal death in normal weight and large‐for‐gestation males born after 28+0 weeks.

Sex selection in late Iberian infant burials: Integrating evidence from morphological and genetic data

OBJECTIVE

The aim of this study was to analyze the infant burials found inside Iberian homes in relation to a possible case of sex selection.

METHODS

The study included the remains of 11 infant individuals buried under the 10 houses excavated in the late Iberian village of Camp de les Lloses (Tona, Barcelona, Spain). Sex was determined using genetic analysis.

RESULTS

Our results showed that almost all the burials were females. However, the age interval of death was wide enough to weaken the premise of infanticide, and the burials probably represent cases of natural death.

DISCUSSION

Infanticide in its different forms has long been argued as an explanation for the infant remains found throughout various burial sites. Many authors thought that infanticide, mainly femicide, was the main method of population control in ancient times. However, there is no anthropological evidence (age distribution and sex analyzed genetically) to support the intentional killing of females in this or in other cases. We hypothesized that there was a positive selection for females to be buried inside the houses, probably related to their benefactor roles.

Modeling and forecasting sex differences in mortality: a sex-ratio approach

Female and male life expectancies have converged in most industrialized societies in recent decades. To achieve coherent forecasts between females and males, this convergence needs to be considered when forecasting sex-specific mortality. We introduce a model forecasting a matrix of the age-specific death rates of sex ratio, decomposed into two age profiles and time indices-before and after age 45-using principal component analysis. Our model allows visualization of both age structure and general level over time of sex differences in mortality for these two age groups. Based on a prior forecast for females, we successfully forecast male mortality convergence with female mortality. The usefulness of the developed model is illustrated by its comparison with other coherent and independent models in an out-of-sample forecast evaluation for 18 countries. The results show that the new proposal outperformed the other models for most countries.

Decomposition of age- and cause-specific adult mortality contributions to the gender gap in life expectancy from census and survey data in Zambia

In the context of high adult mortality and an immense impact on the health burden of Zambia, a decomposition analysis of age- and cause-specific mortality in age group 15–59 was performed to determine the contributions to the gap in life expectancy at birth between males and females. Previous studies on decomposition have examined income groups, ethnicity, and regional differences’ contributions to gaps in life expectancy, but not the adult mortality age group 15–59. These studies focus on developed countries and few on developing countries. Arriaga’s decomposition method was applied to 2010 census and 2010–2012 sample vital registration with verbal autopsy survey (SAVVY) data to decompose contributions of age- and cause-specific adult mortality to the gap in life expectancy at birth between males and females. The decomposition analysis revealed that mortality was higher among males than females and concentrated in age groups 20–49. Age- and cause-specific adult mortality contributed positively, 50% of the years to the gap in life expectancy at birth between males and females. Major cause-specific mortality contributors to the gap in life expectancy were infectious and parasitic diseases (1.17 years, 26.3%), accidents and injuries (0.54 years, 12.2%), suicide and violence (0.30 years, 6.8%). Female HIV mortality offset male mortality. Neoplasms deaths among females contributed negatively to the gap in life expectancy (-0.22 years, -5.4%). Accidents, injuries, suicide, and violence are emerging major causes of death in age group 20–49 in Zambia which health policy and programmes should target.

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Adult mortality contributed half of the years to the gender gap in life expectancy at birth.

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Male mortality in age group 20–49 years contributed most to the gender difference in life expectancy at birth.

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Accidents and injuries, and suicide and violence among males were major positive contributors to the gender gap in life expectancy at birth.

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Female HIV mortality offset male mortality and contributed negatively to the gender life expectancy gap.

Gender differences in the use of anti-infective medications before and after widowhood: a register-based study

BACKGROUND

Recent findings suggest that bereavement due to spousal loss is associated with a decline in general immune functions, and thus to increased susceptibility to infections among widowed individuals. The present study aims to investigate whether spousal loss weakens immune defences more among men than among women using a 5% random sample of the total Danish population, and anti-infective medication use as a proxy for immune response.

METHODS

We followed 6076 Danish individuals (67% women) aged ≥50 from 5 years before and up to 5 years after widowhood to examine changes in prescriptions of anti-infectives for systemic use.

RESULTS

Women used more anti-infective drugs both before and after spousal loss (women: OR= 1.31; 95% CI 1.21 to 1.42). The age-related changes in the use of anti-infective medications in the period before widowhood were similar to that in the period after widowhood among both men and women. Also, age-related changes in the use of anti-infective medications were similar in both genders.

CONCLUSIONS

The present study shows that individuals are more likely to use anti-infective medication after being widowed than before being widowed, but this change is likely to be related to increasing age and it is similar in both genders.

Health related quality of life in patients with community-acquired pneumococcal pneumonia in France

Background

Community Acquired Pneumococcal Pneumonia is a lung infection that causes serious health problems and can lead to complications and death. The aim of this study was to observe and analyze health related quality of life after a hospital episode for patients with community acquired pneumococcal pneumonia in France.

Methods

A total of 524 individuals were enrolled prospectively in the study and were followed for 12 months after hospital discharge. Presence of streptococcus pneumoniae was confirmed by microbiological sampling. Quality of life was reported at four different points of time with the EQ-5D-3 L health states using the French reference tariff. Complete data on all four periods was available for 269 patients.

We used descriptive and econometric analysis to assess quality of life over time during follow-up, and to identify factors that impact the utility indexes and their evolution through time. We used Tobit panel data estimators to deal with the bounded nature of utility values.

Results

Average age of patients was 63 and 55% of patients were men. Negative predictors of quality of life were the severity of the initial event, history of pneumonia, smokers, age and being male. On average, quality of life improved in the first 6 months after discharge and stabilized beyond. At month 1, mean utility index was 0.53 (SD: 0.34) for men and 0.45 (SD: 0.34) for women, versus mean of 0.69 (SD: 0.33) and 0.70 (SD: 0.35) at Month 12. “Usual activities” was the dimension the most impacted by the disease episode. Utilities for men were significantly higher than for women, although male patients were more severe. Individuals over 85 years old did not improve quality of life during follow-up, and quality of life did not improve or deteriorated for 34% of patients. We found that length of hospital stay was negatively correlated with quality of life immediately after discharge.

Conclusion

This study provides with evidence that quality of life after an episode of community acquired pneumococcal pneumonia improves overall until the sixth month after hospital discharge, but older patients with previous history of pneumonia may not experience health gains after the initial episode.

Women live longer than men even during severe famines and epidemics

Women live longer than men in nearly all populations today. Some research focuses on the biological origins of the female advantage; other research stresses the significance of social factors. We studied male–female survival differences in populations of slaves and populations exposed to severe famines and epidemics. We find that even when mortality was very high, women lived longer on average than men. Most of the female advantage was due to differences in mortality among infants: baby girls were able to survive harsh conditions better than baby boys. These results support the view that the female survival advantage is modulated by a complex interaction of biological environmental and social factors.

Women in almost all modern populations live longer than men. Research to date provides evidence for both biological and social factors influencing this gender gap. Conditions when both men and women experience extremely high levels of mortality risk are unexplored sources of information. We investigate the survival of both sexes in seven populations under extreme conditions from famines, epidemics, and slavery. Women survived better than men: In all populations, they had lower mortality across almost all ages, and, with the exception of one slave population, they lived longer on average than men. Gender differences in infant mortality contributed the most to the gender gap in life expectancy, indicating that newborn girls were able to survive extreme mortality hazards better than newborn boys. Our results confirm the ubiquity of a female survival advantage even when mortality is extraordinarily high. The hypothesis that the survival advantage of women has fundamental biological underpinnings is supported by the fact that under very harsh conditions females survive better than males even at infant ages when behavioral and social differences may be minimal or favor males. Our findings also indicate that the female advantage differs across environments and is modulated by social factors.

Tuberculosis mortality and the male survival deficit in rural South Africa: An observational community cohort study

BACKGROUND

Women live on average five years longer than men, and the sex difference in longevity is typically lower in populations with high mortality. South Africa-a high mortality population with a large sex disparity-is an exception, but the causes of death that contribute to this difference are not well understood.

METHODS

Using data from a demographic surveillance system in rural KwaZulu-Natal (2000-2014), we estimate differences between male and female adult life expectancy by HIV status. The contribution of causes of death to these life expectancy differences are computed with demographic decomposition techniques. Cause of death information comes from verbal autopsy interviews that are interpreted with the InSilicoVA tool.

RESULTS

Adult women lived an average of 10.4 years (95% confidence Interval 9.0-11.6) longer than men. Sex differences in adult life expectancy were even larger when disaggregated by HIV status: 13.1 (95% confidence interval 10.7-15.3) and 11.2 (95% confidence interval 7.5-14.8) years among known HIV negatives and positives, respectively. Elevated male mortality from pulmonary tuberculosis (TB) and external injuries were responsible for 43% and 31% of the sex difference in life expectancy among the HIV negative population, and 81% and 16% of the difference among people living with HIV.

CONCLUSIONS

The sex differences in adult life expectancy in rural KwaZulu-Natal are exceptionally large, atypical for an African population, and largely driven by high male mortality from pulmonary TB and injuries. This is the case for both HIV positive and HIV negative men and women, signalling a need to improve the engagement of men with health services, irrespective of their HIV status.

SEX COMPOSITION OF TWINS AND ASSOCIATIONS WITH MORBIDITY, MORTALITY AND MATERNAL TREATMENT-SEEKING OUTCOMES IN RESOURCE-POOR SETTINGS

Societal gender inequality and a preference for male children has been shown to be detrimental to girls' health. This is despite females' innate biological advantage early in life. The negative effects of gender inequity on female health are most pronounced in resource-poor countries, where cultural norms supporting a preference for male children are strongest. However, most of what is known about gender inequality and child health comes from studies of singleton births. There is little evidence for how, or if, the disadvantages associated with gender bias and son preference extend to multiple births, a population inherently at risk for a number of health challenges. This analysis examines whether gender bias in health outcomes exists for twins. Data on live twin births from 38 Demographic and Health Surveys were compiled (n=11,528 individuals) and twins were categorized as girl/girl, girl/boy, boy/girl or girl/girl. Gender inequality was measured via the Gender Inequality Index. Multilevel logistic regression models examined associations between twin sex composition, gender inequality and eight outcomes of infant and child morbidity, mortality and mother's treatment-seeking behaviours. Twin pairs containing girls had significantly lower odds of first-year mortality. Higher country-level gender inequality was associated with higher odds of reporting diarrhoea and fever/cough, as well as an increased odds of post-neonatal mortality. Results suggest that the biological advantage for females may be stronger than son preference and gender inequality in the first year of life. Understanding these relationships has the potential to inform efforts to curb the influence of gender preference on the health of female children in resource-poor settings.

Gender bias in under-five mortality in low/middle-income countries

Introduction

Due to biological reasons, boys are more likely to die than girls. The detection of gender bias requires knowing the expected relation between male and female mortality rates at different levels of overall mortality, in the absence of discrimination. Our objective was to compare two approaches aimed at assessing excess female under-five mortality rate (U5MR) in low/middle-income countries.

Methods

We compared the two approaches using data from 60 Demographic and Health Surveys (2005–2014). The prescriptive approach compares observed mortality rates with historical patterns in Western societies where gender discrimination was assumed to be low or absent. The descriptive approach is derived from global estimates of all countries with available data, including those affected by gender bias.

Results

The prescriptive approach showed significant excess female U5MR in 20 countries, compared with only one country according to the descriptive approach. Nevertheless, both models showed similar country rankings. The 13 countries with the highest and the 10 countries with the lowest rankings were the same according to both approaches. Differences in excess female mortality among world regions were significant, but not among country income groups.

Conclusion

Both methods are useful for monitoring time trends, detecting gender-based inequalities and identifying and addressing its causes. The prescriptive approach seems to be more sensitive in the identification of gender bias, but needs to be updated using data from populations with current-day structures of causes of death.

Excess Male Infant Mortality: The Gene-Institution Interactions

Excess male mortality at early ages is an important source of child inequality in most societies. We examine how improvement in the quality of political institutions affects the male survival disadvantage. Using data on twins in combination with a natural experiment on the development of African institutions, we quantify the distinct effects of biology and preconception environment on the infant mortality sex gap and find that these effects are important only in poor institutions. The analysis implies that improved institutions constrain genetic expression and mitigate preconception influences on excess male infant mortality, which is an optimistic finding with pragmatic implications.

Influence of malnutrition upon all-cause mortality among children in Swaziland

OBJECTIVE

To analyze the effect of the type of malnutrition, sex, age and the presence of edema upon all-cause mortality in children under 5 years of age.

MATERIAL AND METHODS

A cross-sectional study was conducted during 2010 and 2011 in Swaziland. Sex, age, weight and height were taken to classify nutritional status according to the 2006 WHO growth standards: stunting (low height for age), wasting (low weight for height or low body mass index for age) and underweight (low weight for age). The sample (309 boys and 244 girls under 5 years of age) was analyzed by sex and age groups (under and equal/over 12 months). The association between variables was evaluated using the χ² test. Cox regression analysis (HR, 95% CI) was used to assess the likelihood of mortality.

RESULTS

The mortality risk in malnourished children under one year of age was lower among females and increased in the presence of severe edema. Wasting combined with underweight increased the mortality risk in children under 12 months of age 5-fold, versus 11-fold in older children. The combination of stunting, wasting and underweight was closely associated to mortality. Stunting alone (not combined with wasting) did not significantly increase the mortality risk.

CONCLUSIONS

Sex, severe edema and wasting are predictors of mortality in malnourished children. Regardless of these factors, children with deficiencies referred to weight for height and weight for age present a greater mortality risk in comparison with children who present stunting only.

Child Gender and Parental Reporting of Illness Symptoms in Sub-Saharan Africa

AbstractThe overwhelming majority of evidence about the health of children in low- and middle-income countries is based on reports by parents. There is limited evidence on whether these reports suffer from systematic bias, particularly related to the gender of the child. We investigate differences in symptom reporting by child gender in a sample of countries in sub-Saharan Africa. Data from 35 Demographic and Health Surveys and 10 Malaria Indicator Surveys conducted since 2005 were analyzed. Parental reports of child symptoms were compared for girls and boys. In a subsample of data from Nigeria, we also compared the accuracy of parental reports of fever between girls and boys. Then, potential explanations for observed reporting differences were explored. Finally, country-level relationships between gender differences in symptom reporting and differences in child health outcomes were estimated. Parents reported fewer episodes of fever and diarrhea for girls as compared with boys. Less frequent symptom reporting for girls does not appear to be due to reduced exposure to illness-causing agents nor increased treatment seeking. Lower fever reporting for girls relative to boys is associated with higher relative infant mortality for girls at the country level, consistent with a potential link between underreporting and health outcomes. From a measurement perspective, estimates of gender imbalances in child morbidity and treatment based on parental reports may be inaccurate. From a public health perspective, parental underreporting of symptoms in girls may indicate untreated illness that goes unnoticed.

The landscape of sex-differential transcriptome and its consequent selection in human adults

BACKGROUND

The prevalence of several human morbid phenotypes is sometimes much higher than intuitively expected. This can directly arise from the presence of two sexes, male and female, in one species. Men and women have almost identical genomes but are distinctly dimorphic, with dissimilar disease susceptibilities. Sexually dimorphic traits mainly result from differential expression of genes present in both sexes. Such genes can be subject to different, and even opposing, selection constraints in the two sexes. This can impact human evolution by differential selection on mutations with dissimilar effects on the two sexes.

RESULTS

We comprehensively mapped human sex-differential genetic architecture across 53 tissues. Analyzing available RNA-sequencing data from 544 adults revealed thousands of genes differentially expressed in the reproductive tracts and tissues common to both sexes. Sex-differential genes are related to various biological systems, and suggest new insights into the pathophysiology of diverse human diseases. We also identified a significant association between sex-specific gene transcription and reduced selection efficiency and accumulation of deleterious mutations, which might affect the prevalence of different traits and diseases. Interestingly, many of the sex-specific genes that also undergo reduced selection efficiency are essential for successful reproduction in men or women. This seeming paradox might partially explain the high incidence of human infertility.

CONCLUSIONS

This work provides a comprehensive overview of the sex-differential transcriptome and its importance to human evolution and human physiology in health and in disease.

The weaker sex? Vulnerable men and women's resilience to socio-economic disadvantage

Sex differences in mortality vary over time and place as a function of social, health, and medical circumstances. The magnitude of these variations, and their response to large socioeconomic changes, suggest that biological differences cannot fully account for sex differences in survival. Drawing on a wide swath of mortality data across countries and over time, we develop a set of empiric observations with which any theory about excess male mortality and its correlates will have to contend. We show that as societies develop, M/F survival first declines and then increases, a "sex difference in mortality transition" embedded within the demographic and epidemiologic transitions. After the onset of this transition, cross-sectional variation in excess male mortality exhibits a consistent pattern of greater female resilience to mortality under socio-economic adversity. The causal mechanisms underlying these associations merit further research.

Sex differences in mortality in Denmark during half a century, 1943-92

Objective: The emphasis of this study is on the relative mortality of 45 - 74-year-old men and women in Denmark in 1943-92, following economic and political changes that have affected the social meaning of gender over the last 50 years, and which have diminished former sex differences in health behaviour. Methods: Sex ratios of total mortality and mortality from major non-sex-specific causes of death were calculated on computerized mortality data from the Danish National Cause of Death Register that covers all deaths in Denmark since 1943. Results: In the early 1940s the sex ratio of all-cause mortality was low, 1.0-1.1, it increased to a peak level in the late 1970s and early 1980s, but has since decreased due to an increase in female mortality and a more favourable trend in male mortality. Conclusion: Gender equality, employment, and economic autonomy may have beneficial health effects on both men and women, but the effects are inconsistent. The trend in smoking is the major explanatory factor for the more recent trends in gender differentials in mortality in Denmark.

Handedness and Age of Death: New Evidence on a Puzzling Relationship

Based on 5743 deaths in the United States and Canada, the present study was undertaken to verify and extend results suggesting that left handers have a shorter life expectancy than right handers. Unlike previous studies, which have merely dichotomized handedness, this study used a 5-point scale to measure handedness (extremely right handed, generally right handed, ambidextrous, generally left handed and extremely left handed). We found a significant tendency for one of the five handedness categories—those classified as generally left handers—to die at a significantly younger age than was true for the other four handedness groups. Our findings add to the controversy over links between handedness and age of death by suggesting that only a portion of left handers are at risk of premature death.

Changes in life expectancy 1950-2010: contributions from age- and disease-specific mortality in selected countries

Background

Changes of life expectancy over time serve as an interesting public health indicator for medical, social and economic developments within populations. The aim of this study was to quantify changes of life expectancy between 1950 and 2010 and relate these to main causes of death.

Methods

Pollard’s actuarial method of decomposing life expectancy was applied to compare the contributions of different age- and disease-groups on life expectancy in 5-year intervals.

Results

From the 1960 to 70s on, declines in cardiovascular disease (CVD) mortality play an increasing role in improving life expectancy in many developed countries. During the past decades gains in life expectancy in these countries were mainly observed in age groups ≥65 years. A further consistent pattern was that life expectancy increases were stronger in men than in women, although life expectancy is still higher in women. In Japan, an accelerated epidemiologic transition in causes of death was found, with the highest increases between 1950 and 1955. Short-term declines and subsequent gains in life expectancy were observed in Eastern Europe and the former states of the Union of Soviet Socialist Republics (USSR), reflecting the changes of the political system.

Conclusions

Changes of life years estimated with the decomposing method can be directly interpreted and may therefore be useful in public health communication. The development within specific countries is highly sensitive to changes in the political, social and public health environment.

Electronic supplementary material

The online version of this article (doi:10.1186/s12963-016-0089-x) contains supplementary material, which is available to authorized users.

The large contribution of twins to neonatal and post-neonatal mortality in The Gambia, a 5-year prospective study

BACKGROUND

A high twinning rate and an increased risk of mortality among twins contribute to the high burden of infant mortality in Africa. This study examined the contribution of twins to neonatal and post-neonatal mortality in The Gambia, and evaluated factors that contribute to the excess mortality among twins.

METHODS

We analysed data from the Basse Health and Demographic Surveillance System (BHDSS) collected from January 2009 to December 2013. Demographic and epidemiological variables were assessed for their association with mortality in different age groups.

RESULTS

We included 32,436 singletons and 1083 twins in the analysis (twining rate 16.7/1000 deliveries). Twins represented 11.8 % of all neonatal deaths and 7.8 % of post-neonatal deaths. Mortality among twins was higher than in singletons [adjusted odds ratio (AOR) 4.33 (95 % CI: 3.09, 6.06) in the neonatal period and 2.61 (95 % CI: 1.85, 3.68) in the post-neonatal period]. Post-neonatal mortality among twins increased in girls (P for interaction = 0.064), being born during the dry season (P for interaction = 0.030) and lacking access to clean water (P for interaction = 0.042).

CONCLUSION

Mortality among twins makes a significant contribution to the high burden of neonatal and post-neonatal mortality in The Gambia and preventive interventions targeting twins should be prioritized.

Gender perceptions predict sex differences in growth patterns of indigenous Guatemalan infants and young children

BACKGROUND

Nearly one-half of Guatemalan children experience growth faltering, more so in indigenous than in nonindigenous children.

OBJECTIVES

On the basis of ethnographic interviews in Totonicapán, Guatemala, which revealed differences in maternal perceptions about food needs in infant girls and boys, we predicted a cumulative sex difference in favor of girls that occurred at ∼6 mo of age and diminished markedly thereafter. We examined whether the predicted differences in age-sex patterns were observed in the village, replicated the examination nationally for indigenous children, and examined whether the pattern in nonindigenous children was different.

DESIGN

Ethnographic interviews (n = 24) in an indigenous village were conducted. Anthropometric measurements of the village children aged 0-35 mo (n = 119) were obtained. National-level growth patterns were analyzed for indigenous (n = 969) and nonindigenous (n = 1374) children aged 0-35 mo with the use of Demographic and Health Survey (DHS) data.

RESULTS

Mothers reported that, compared with female infants, male infants were hungrier, were not as satisfied with breastfeeding alone, and required earlier complementary feeding. An anthropometric analysis confirmed the prediction of healthier growth in indigenous girls than in indigenous boys throughout the first year of life, which resulted in a 2.98-cm height-for-age difference (HAD) between sexes in the village and a 1.61-cm HAD (P < 0.001) in the DHS data between 6 and 17 mo of age in favor of girls. In both data sets, the growth sex differences diminished in the second year of life (P < 0.05). No such pattern was seen in nonindigenous children.

CONCLUSIONS

We propose that the differences in the HAD that first favor girls and then favor boys in the indigenous growth patterns are due to feeding patterns on the basis of gendered cultural perceptions. Circumstances that result in differential sex growth patterns need to be elucidated, in particular the favorable growth in girls in the first year of life.

Bayesian spatial analysis of childhood diseases in Zimbabwe

BACKGROUND

Many sub-Saharan countries are confronted with persistently high levels of childhood morbidity and mortality because of the impact of a range of demographic, biological and social factors or situational events that directly precipitate ill health. In particular, under-five morbidity and mortality have increased in recent decades due to childhood diarrhoea, cough and fever. Understanding the geographic distribution of such diseases and their relationships to potential risk factors can be invaluable for cost effective intervention.

METHODS

Bayesian semi-parametric regression models were used to quantify the spatial risk of childhood diarrhoea, fever and cough, as well as associations between childhood diseases and a range of factors, after accounting for spatial correlation between neighbouring areas. Such semi-parametric regression models allow joint analysis of non-linear effects of continuous covariates, spatially structured variation, unstructured heterogeneity, and other fixed effects on childhood diseases. Modelling and inference made use of the fully Bayesian approach via Markov Chain Monte Carlo (MCMC) simulation techniques. The analysis was based on data derived from the 1999, 2005/6 and 2010/11 Zimbabwe Demographic and Health Surveys (ZDHS).

RESULTS AND CONCLUSIONS

The results suggest that until recently, sex of child had little or no significant association with childhood diseases. However, a higher proportion of male than female children within a given province had a significant association with childhood cough, fever and diarrhoea. Compared to their counterparts in rural areas, children raised in an urban setting had less exposure to cough, fever and diarrhoea across all the survey years with the exception of diarrhoea in 2010. In addition, the link between sanitation, parental education, antenatal care, vaccination and childhood diseases was found to be both intuitive and counterintuitive. Results also showed marked geographical differences in the prevalence of childhood diarrhoea, fever and cough. Across all the survey years Manicaland province reported the highest cases of childhood diseases. There is also clear evidence of significant high prevalence of childhood diseases in Mashonaland than in Matabeleland provinces.

The impact of smoking on gender differences in life expectancy: more heterogeneous than often stated

Background: Throughout industrialized countries, tobacco consumption is seen as the predominant driver of both the trend and the extent of gender differences in life expectancy. However, several factors raise doubts to this generalization. We hypothesize that the impact of smoking on the gender gap is context-specific and differs between populations. Methods: We decompose the gender differences in life expectancy into fractions caused by smoking and other non-biological factors for 53 industrialized countries and the period 1955–2009 to assess the significance of smoking among the causes that can be influenced by direct or indirect interference. Results: The trend of the gender gap can indeed be attributed to smoking in most populations of the western world. However, with regard to the overall extent of male excess mortality, smoking is the main driver only in the minority of the studied populations. While the impact of smoking to gender differences in life expectancy declines in all populations, the contribution of other non-biological factors is in most cases higher at the end than at the beginning of the observation period. Conclusions: Over-generalized statements suggesting that smoking is the main driver of the gender gap in all populations can be misleading. The results of this study demonstrate that—regardless of the prevailing effect of smoking—many populations have still remarkable potentials to further narrow their gender gaps in life expectancy. Although measures to further reduce the prevalence of tobacco consumption must be continued, more attention should be directed to the growing importance of other non-biological factors.

Cause-specific neonatal deaths in rural Bangladesh, 1987-2005: levels, trends, and determinants

This paper reports on an analysis of neonatal mortality from communicable and non-communicable diseases in Bangladesh. The competing-risks model employed incorporated both observed and unobserved heterogeneity and allowed the two heterogeneity terms to be correlated. The data used came from the Health and Demographic Surveillance System, Matlab. The results confirm the conclusions of previous studies about the levels, trends, and causes of neonatal death in the Matlab area: the education of the mother helps protect her children from death from both communicable and non-communicable diseases; the children of a father in a low-status occupation are particularly vulnerable to death from communicable diseases; and children born to mothers aged less than 20 face a particularly high risk of dying from a non-communicable disease. The risks of dying from a communicable disease and from a non-communicable disease were both found to fall significantly as the distance to the nearest health centre decreased.

Early life effects across the life course: the impact of individually defined exogenous measures of disease exposure on mortality by sex in 19th- and 20th-century Southern Sweden

Using micro-level longitudinal data from Southern Sweden for 1813 to 1968, this work evaluates the effect of exposure to disease in early life on mortality over the entire life course and separately by sex. The local rates of post-early neonatal mortality are considered indicators of early life disease exposure, and these rates are calculated specifically for each person based on birth date. The loss in median remaining life among exposed individuals who survived to age 1 is 1.1 years for females and 2.1 years for males. Exposed individuals show a cross-over from lower to higher relative mortality as they age. This change occurs in adulthood for males and in old age for females. During adulthood, exposed males present higher rates of death than exposed females. These results are new to the literature and shed light on the importance of adopting a full life course approach and capturing sex differences when evaluating the long-term impacts of early life exposures.

Exposure to childhood traumas ups the odds of giving birth to daughters

This study examined the likelihood of giving birth to a daughter as a function of women's exposure to four categories of stressors: childhood trauma, adult trauma, chronic stressors, and recent (adverse) life events. Hypothesis 1 stated that exposure to recent life events (near conception) and to childhood traumas would increase women's chances of having a girl baby. Hypothesis 2 stated that the relationship between stress and gender outcome is mediated by persistent posttraumatic stress disorder (PTSD) symptoms. The final sample was comprised of 225 women. The design was prospective observational. At first contact, women were retained if they were <27 weeks pregnant and met initial inclusion criteria. In interview 2, at 27-30 weeks, women were excluded for positive diagnoses of anxiety disorders besides PTSD with or without depression (Structured Clinical Interview for DSM-IV Disorders). In interview 3 (30-34 weeks), reports on stress categories (Social Stress Indicator Questionnaire) and PTSD symptoms (Post-Traumatic Checklist) were obtained. Infant gender was obtained from medical records. The relationship between stress categories and the distribution of girl/boy infants was examined with Chi Squares and logistic regression analyses. Mediation was tested with the macro PROCESS (Hayes 2012). Childhood trauma was the only stress category that increased the odds of having a girl, with an odds ratio of >3.0 for women who had been exposed to more than two such events. PTSD symptoms (partially) mediated the relationship between childhood trauma and infant gender. Findings suggest that women's exposure to childhood trauma contributes to the determination of the sex ratio at birth and that PTSD symptoms are part of the cause.

Effect of gender preference on fertility: cross-sectional study among women of Tharu community from rural area of eastern region of Nepal

Background

Son preference is predominant in developing countries especially South Asian countries and its effect is most visible when the fertility is on transition. Nepal is a country in South Asia where the fertility has declined and son is valued highly. This study examines the parent’s gender preference for children and its effect on fertility and reproductive behaviors.

Methods

Study was conducted in Sonapur village development committee of Sunsari district among women of Tharu community of reproductive age (15–49) currently in union and having at least one child. Data was collected by house to house survey. Data was analyzed with IBM SPSS 20 version. Multinomial and binary logistic regression were used to analyze the relationship among variables.

Results

Three hundred women of reproductive age were included in the study. Current average age of the respondents was 31.97 years and mean age at marriage was 18.87 (SD +/-2.615). Child Sex ratio (male: female) of the respondents who didn’t want any more children was 1.41. The birth spacing following male baby was 3.09 years whereas the average birth spacing following female baby was 2.71 years. Age of the respondents and education status of the respondents were also significantly associated with contraceptive practice. Presence of only female children in family significantly increased the desire of other children (AOR = 10.153, 95% CI = 2.357-43.732).

Conclusion

This study finds that the gender preference affects the fertility and reproductive behavior of the respondents and it is necessary to reduce son preference for the health and well being of children and women.

Mortality increase in late-middle and early-old age: heterogeneity in death processes as a new explanation

Deviations from the Gompertz law of exponential mortality increases in late-middle and early-old age are commonly neglected in overall mortality analyses. In this study, we examined mortality increase patterns between ages 40 and 85 in 16 low-mortality countries and demonstrated sex differences in these patterns, which also changed across period and cohort. These results suggest that the interaction between aging and death is more complicated than what is usually assumed from the Gompertz law and also challenge existing biodemographic hypotheses about the origin and mechanisms of sex differences in mortality. We propose a two-mortality model that explains these patterns as the change in the composition of intrinsic and extrinsic death rates with age. We show that the age pattern of overall mortality and the population heterogeneity therein are possibly generated by multiple dynamics specified by a two-mortality model instead of a uniform process throughout most adult ages.

Why is infant mortality higher in boys than in girls? A new hypothesis based on preconception environment and evidence from a large sample of twins

Infant mortality is higher in boys than girls in most parts of the world. This has been explained by sex differences in genetic and biological makeup, with boys being biologically weaker and more susceptible to diseases and premature death. At the same time, recent studies have found that numerous preconception or prenatal environmental factors affect the probability of a baby being conceived male or female. I propose that these environmental factors also explain sex differences in mortality. I contribute a new methodology of distinguishing between child biology and preconception environment by comparing male-female differences in mortality across opposite-sex twins, same-sex twins, and all twins. Using a large sample of twins from sub-Saharan Africa, I find that both preconception environment and child biology increase the mortality of male infants, but the effect of biology is substantially smaller than the literature suggests. I also estimate the interacting effects of biology with some intrauterine and external environmental factors, including birth order within a twin pair, social status, and climate. I find that a twin is more likely to be male if he is the firstborn, born to an educated mother, or born in certain climatic conditions. Male firstborns are more likely to survive than female firstborns, but only during the neonatal period. Finally, mortality is not affected by the interactions between biology and climate or between biology and social status.