A divergent pattern of the sex difference in life expectancy: Sweden and Japan, early 1970s-late 1990s

For most of the 20th century the sex gap in life expectancy in the industrialized countries has widened in favor of women. By the early 1980s a reversal in the long-term pattern of this differential had occurred in some countries, where it reached a maximum and thereafter followed a declining trend. Of particular interest to the present investigation is the anomalous experience of Japan, where unlike other high-income countries the female advantage in life expectancy has been expanding. We contrast the case of Japan with that of Sweden, where, like many other high-income nations, the sex differential in longevity has been narrowing in recent years. We observe that in Sweden, until the early 1980s, the sex gap in life expectancy (female-male) exceeded that of Japan; but this situation reversed in subsequent periods, when the Swedish differential narrowed and that of Japan widened. A decomposition analysis indicates that these divergent patterns since 1980 have resulted mainly from larger than expected reductions in male mortality in Sweden due to heart disease and from accidents and violence, lung cancer and "other" cancers. In Japan, death rates for men and women from heart disease--which is a leading cause of death--have tended to decline more or less at the same pace since the early 1980s; and with regard to lung cancer, and "other" neoplasms, male death rates in Japan have been rising while those of women have either declined or risen more slowly. Moreover, during the 1990s, male and female suicide rates rose in Japan, but the rates for men went up faster. Altogether, the net effect of these divergent mortality trends for men and women in Japan underlie much of the observed widening of its sex differential in longevity in recent years.     

Narrowing sex differentials in life expectancy in the industrialized world: Early 1970's to early 1990's

Abstract

Between the early 1970's and 1990's, twelve industrialized nations experienced for the first time a narrowing of their sex differences in life expectancy at age zero. In another set of countries, the differential has not yet reached a stage of convergence, although in some of these nations the female advantage appears to be increasing at a slower pace than ever before. We discuss the demographic and epidemiologic conditions for this new and largely unanticipated trend, as well as its applied and theoretical implications in the context of the following questions: (1) Is the observed change a function of males’ faster pace of gains in life expectancy since the early 1970s? (2) What is the relationship between country differences in socioeconomic development (as measured by GNP) and the degree of convergence in the sex gap in average length of life? (3) What is the degree of association between temporal change in age‐sex specific death rates and change in the sex gap in life expectancy over the twenty‐year interval between the early 1970s and early 1990s? Our results indicate that where some convergence has taken place, in relation to women, men have experienced more rapid gains in survival; the higher a nation's level of social and economic development, the greater the amount of convergence in male and female life expectancies. The most pronounced age‐specific association with the changing sex gap in longevity is that of ages 25–59, where the greater reductions in male mortality, as compared to that for females, contributed to a significant portion of the observed convergence in life expectancy across industrialized nations.     

Canadian Indian mortality during the 1980s

This study concerns itself with an investigation of general and cause-specific mortality differentials between Canadian Registered Indians (a subset of all aboriginals) and the larger Canadian population over two points in time, 1981 and 1991. Multivariate analyses are executed separately across four segments of the life cycle: adulthood, infancy, early childhood and late childhood. With respect to adults, Indians share relatively high rates of suicide, homicide and accidental causes of death; over time, their conditional risks of death due to cancer and circulatory afflictions have gone up significantly. Mortality disadvantages for the Indians are also pronounced in infancy, early childhood (ages 1-4) and late childhood (ages 5-14). Suicide, accidents, and violence constitute serious problems among 5-14 year olds, while infectious/parasitic, respiratory and circulatory complications, plus accidents and violence, are principle killers in infancy. For children aged 1-4, respiratory problems and accidents/violence are prime causes of premature death. This less-than-optimal mortality profile is reflective of persistent problems associated with prolonged socioeconomic marginalization. The temporal pattern of change in chronic/degenerative disease mortality among adult Indians suggests a movement of this population toward a mature stage of epidemiological transition.     

Health transition: examples from the western Pacific.

The Industrial Revolution ushered in a rapid transition from agriculture to industrialization. Some biological effects of this transition included increasing life expectancy, reduced infant mortality, and some decline in fertility. Reduced infant mortality first brought about an increase in life expectancy, but as humans were able to control infectious diseases, child and adult mortality also decreased. Now, accidents and chronic diseases are responsible for most mortality in many age groups. This shift from infectious diseases to accidents and chronic diseases is called the health transition. Japan and US are Pacific Basin countries which have relatively high life expectancy and low infant mortality (1988, 75.54 years vs. 71.38 years, and 4.4 vs. 9.9, respectively). These figures suggest that these countries rather advanced in the health transition. Japan may have better life expectancy than the US because of the effect of environmental factors, ethnic diversity, and health care differentials by social class on cardiovascular disease and cancer mortality. China and Thailand hold intermediate positions (67.98 years (1985-1990) vs. 63.82 years (1985-1986), and 32.4 vs. 39, respectively). Some research indicates that urban conditions and factory work increase the cardiovascular disease risk among the Chinese. Recent research suggests that access to immunization and modern medical care for acute disease are the only critical variables of the health transition rather than other variables. Papua New Guinea is not progressing very well (53.18 years and 58). Papua New Guinea has not yet been able to control infectious diseases, especially malaria. This comparison illustrates that populations progress through the health transition at different rates.     

The Changing Gender Differences in Life Expectancy in Chinese Cities 2005-2010

Objectives

To analyze the gender difference in life expectancy in Chinese urban people and explore the age-specific and cause-specific contributions to the changing gender differences in life expectancy.

Methods

Data of life expectancy and mortality were obtained from “Annual statistics of public health in China.” The gender difference was analyzed by decomposition method, including age-specific decomposition and cause-specific decomposition.

Results

Women lived much longer than men in Chinese urban areas, with remarkable gains in life expectancy since 2005, respectively. The gender difference reached a peak in 2007. Mortality difference between men and women in the 60–79 age group made the largest contributions to the gender gap in life expectancy in all 6 years. Among causes of death, cancers, circulatory diseases and respiratory diseases made the largest contributions to the gender gap. 33–38% of the gender gap were caused by cancers, among which lung cancer contributed 0.6 years of the overall gap. The contribution of cancers to the gender gap reduced over time, mostly influenced by the narrowing effect of liver cancer on gender gap. Traffic accidents and suicide were the external causes influencing the gender gap, contributing 10–16% of the overall difference.

Conclusion

Public health efforts to reduce excess mortalities for cancers, circulatory disease, respiratory diseases, and suicide among men in particular might further narrow the gender gap in life expectancy in Chinese cities.     

Life Expectancy and Death by Diseases of the Circulatory System in Patients with Bipolar Disorder or Schizophrenia in the Nordic Countries

Objective

Excess mortality from diseases and medical conditions (natural death) in persons with psychiatric disorders has been extensively reported. Even in the Nordic countries with well-developed welfare systems, register based studies find evidence of an excess mortality. In recent years, cardiac mortality and death by diseases of the circulatory system has seen a decline in all the Nordic countries, but a recent paper indicates that women and men in Denmark, Finland, and Sweden, who had been hospitalised for a psychotic disorder, had a two to three-fold increased risk of dying from a cardiovascular disease. The aim of this study was to compare the mortality by diseases of the circulatory system among patients with bipolar disorder or schizophrenia in the three Nordic countries Denmark, Sweden, and Finland. Furthermore, the aim was to examine and compare life expectancy among these patients. Cause specific Standardized Mortality Rates (SMRs) were calculated for each specific subgroup of mortality. Life expectancy was calculated using Wiesler’s method.

Results

The SMR for bipolar disorder for diseases of the circulatory system was approximately 2 in all countries and both sexes. SMR was slightly higher for people with schizophrenia for both genders and in all countries, except for men in Denmark. Overall life expectancy was much lower among persons with bipolar disorder or schizophrenia, with life expectancy being from 11 to 20 years shorter.

Conclusion

Our data show that persons in the Nordic countries with schizophrenia or bipolar disorder have a substantially reduced life expectancy. An evaluation of the reasons for these increased mortality rates should be prioritized when planning healthcare in the coming years.     

Impact of Pregnancy-Related Deaths on Female Life Expectancy in Zambia: Application of Life Table Techniques to Census Data

Introduction

Since 2000, the world has been coalesced around efforts to reduce maternal mortality. However, few studies have estimated the significance of eliminating maternal deaths on female life expectancy. We estimated, based on census data, the potential gains in female life expectancy assuming complete elimination of pregnancy-related mortality in Zambia.

Methods

We used data on all-cause and pregnancy-related deaths of females aged 15–49 reported in the Zambia 2010 census, and evaluated, adjusted and smoothed them using existing and verified techniques. We used associated single decrement life tables, assuming complete elimination of pregnancy-related deaths to estimate the potential gains in female life expectancy at birth, at age 15, and over the ages 15–49. We compared these gains with the gains from eliminating deaths from accidents, injury, violence and suicide.

Results

Complete elimination of pregnancy-related deaths would extend life expectancy at birth among Zambian women by 1.35 years and life expectancy at age 15 by 1.65 years. In rural areas, this would be 1.69 years and 2.19 years, respectively, and in urban areas, 0.78 years and 0.85 years. An additional 0.72 years would be spent in the reproductive age group 15–49; 1.00 years in rural areas and 0.35 years in urban areas. Eliminating deaths from accidents, injury, suicide and violence among women aged 15–49 would cumulatively contribute 0.55 years to female life expectancy at birth.

Conclusion

Eliminating pregnancy-related mortality would extend female life expectancy in Zambia substantially, with more gains among adolescents and females in rural areas. The application of life table techniques to census data proved very valuable, although rigorous evaluation and adjustment of reported deaths and age was necessary to attain plausible estimates. The collection of detailed high quality cause-specific mortality data in future censuses is indispensable.     

Canadian Indian mortality during the 1980s

Abstract

This study concerns itself with an investigation of general and cause‐specific mortality differentials between Canadian Registered Indians (a subset of all aboriginals) and the larger Canadian population over two points in time, 1981 and 1991. Multivariate analyses are executed separately across four segments of the life cycle: adulthood, infancy, early childhood and late childhood. With respect to adults, Indians share relatively high rates of suicide, homicide and accidental causes of death; over time, their conditional risks of death due to cancer and circulatory afflictions have gone up significantly. Mortality disadvantages for the Indians are also pronounced in infancy, early childhood (ages 1–4) and late childhood (ages 5–14). Suicide, accidents, and violence constitute serious problems among 5–14 year olds, while infectious/parasitic, respiratory and circulatory complications, plus accidents and violence, are principle killers in infancy. For children aged 1–4, respiratory problems and accidents/violence are prime causes of premature death. This less‐than‐optimal mortality profile is reflective of persistent problems associated with prolonged socioeconomic marginalization. The temporal pattern of change in chronic/degenerative disease mortality among adult Indians suggests a movement of this population toward a mature stage of epidemiological transition.     

Child Mortality Estimation: Estimating Sex Differences in Childhood Mortality since the 1970s

Introduction

Producing estimates of infant (under age 1 y), child (age 1–4 y), and under-five (under age 5 y) mortality rates disaggregated by sex is complicated by problems with data quality and availability. Interpretation of sex differences requires nuanced analysis: girls have a biological advantage against many causes of death that may be eroded if they are disadvantaged in access to resources. Earlier studies found that girls in some regions were not experiencing the survival advantage expected at given levels of mortality. In this paper I generate new estimates of sex differences for the 1970s to the 2000s.

Methods and Findings

Simple fitting methods were applied to male-to-female ratios of infant and under-five mortality rates from vital registration, surveys, and censuses. The sex ratio estimates were used to disaggregate published series of both-sexes mortality rates that were based on a larger number of sources. In many developing countries, I found that sex ratios of mortality have changed in the same direction as historically occurred in developed countries, but typically had a lower degree of female advantage for a given level of mortality. Regional average sex ratios weighted by numbers of births were found to be highly influenced by China and India, the only countries where both infant mortality and overall under-five mortality were estimated to be higher for girls than for boys in the 2000s. For the less developed regions (comprising Africa, Asia excluding Japan, Latin America/Caribbean, and Oceania excluding Australia and New Zealand), on average, boys'' under-five mortality in the 2000s was about 2% higher than girls''. A number of countries were found to still experience higher mortality for girls than boys in the 1–4-y age group, with concentrations in southern Asia, northern Africa/western Asia, and western Africa. In the more developed regions (comprising Europe, northern America, Japan, Australia, and New Zealand), I found that the sex ratio of infant mortality peaked in the 1970s or 1980s and declined thereafter.

Conclusions

The methods developed here pinpoint regions and countries where sex differences in mortality merit closer examination to ensure that both sexes are sharing equally in access to health resources. Further study of the distribution of causes of death in different settings will aid the interpretation of differences in survival for boys and girls. Please see later in the article for the Editors'' Summary.     

Health and social inequality in Europe.

In most European countries health has been shown to be linked to social circumstances--gradients in health status have persisted for decades, despite major changes in the principal causes of death. In central and eastern Europe life expectancy has stagnated since the mid-60s, whereas in the West it has increased; but even in the West it is related to income distribution. Social differences in mortality in men are three times as large in some countries as in others, and are influenced by factors other than conventional risk factors. Substantial declines in mortality and morbidity could result from a narrowing of health inequalities even when differences in health risk between social groups are comparatively small. Policies to reduce health inequalities can be introduced in smaller communities and organisations such as the school and workplace. National policies are variable; factors generating inequalities require action across several policy areas.     

Contribution of deaths related to alcohol use of socioeconomic variation in mortality: register based follow up study.

OBJECTIVE: To estimate the contribution of excessive alcohol use to socioeconomic variation in mortality among men and women in Finland. DESIGN: Register based follow up study. SUBJECTS: The population covered by the 1985 and 1990 censuses, aged > or = 20 in the follow up period 1987-93. MAIN OUTCOME MEASURES: Total mortality and alcohol related mortality from all causes, from diseases, and from accidents and violence according to socioeconomic position. The excess mortality among other classes compared with upper non-manual employees and differences in life expectancy between the classes were used to measure mortality differentials. RESULTS: Alcohol related mortality constituted 11% of all mortality among men aged > or = 20 and 2% among women and was higher among manual workers than among other classes. It accounted for 14% of the excess all cause mortality among manual workers over upper non-manual employees among men and 4% among women and for 24% and 9% of the differences in life expectancy, respectively. Half of the excess mortality from accidents and violence among male manual workers and 38% among female manual workers was accounted for by alcohol related deaths, whereas in diseases the role of alcohol was modest. The contribution of alcohol related deaths to relative mortality differentials weakened with age. CONCLUSIONS: Class differentials in alcohol related mortality are an important factor in the socioeconomic mortality differentials in Finland, especially among men, among younger age groups, and in mortality from accidents and violence.     

Sex differences in life expectancy in Canada: immigrant and native-born populations

A growing body of research often indicates that immigrant populations in Western countries enjoy a lower level of mortality in relation to their native-born host populations. In this literature, sex differences in mortality are often reported but substantive analyses of the differences are generally lacking. The present investigation looks at sex differences in life expectancy with specific reference to immigrant and Canadian-born populations in Canada during 1971 and 2001. For these two populations, sex differences in expectation of life at birth are decomposed into cause-of-death components. Immigrants in Canada have a higher life expectancy than their Canadian-born counterparts. In absolute terms, immigrant females enjoy the highest life expectancy. In relative terms, however, immigrant men show a larger longevity advantage, as their expectation of life at birth exceeds that of Canadian-born men by a wider margin than do foreign-born females in relation to Canadian-born females. It is also found that immigrants have a smaller sex differential in life expectancy as compared with the Canadian born. Decomposition analysis shows this is a function of immigrants having smaller sex differences in death rates from heart disease and cancer. Factors thought to underlie these differentials between immigrants and the Canadian born are discussed and suggestions for further research are given.     

Regional Changes in Charcoal-Burning Suicide Rates in East/Southeast Asia from 1995 to 2011: A Time Trend Analysis

Background

Suicides by carbon monoxide poisoning resulting from burning barbecue charcoal reached epidemic levels in Hong Kong and Taiwan within 5 y of the first reported cases in the early 2000s. The objectives of this analysis were to investigate (i) time trends and regional patterns of charcoal-burning suicide throughout East/Southeast Asia during the time period 1995–2011 and (ii) whether any rises in use of this method were associated with increases in overall suicide rates. Sex- and age-specific trends over time were also examined to identify the demographic groups showing the greatest increases in charcoal-burning suicide rates across different countries.

Methods and Findings

We used data on suicides by gases other than domestic gas for Hong Kong, Japan, the Republic of Korea, Taiwan, and Singapore in the years 1995/1996–2011. Similar data for Malaysia, the Philippines, and Thailand were also extracted but were incomplete. Graphical and joinpoint regression analyses were used to examine time trends in suicide, and negative binomial regression analysis to study sex- and age-specific patterns. In 1995/1996, charcoal-burning suicides accounted for <1% of all suicides in all study countries, except in Japan (5%), but they increased to account for 13%, 24%, 10%, 7%, and 5% of all suicides in Hong Kong, Taiwan, Japan, the Republic of Korea, and Singapore, respectively, in 2011. Rises were first seen in Hong Kong after 1998 (95% CI 1997–1999), followed by Singapore in 1999 (95% CI 1998–2001), Taiwan in 2000 (95% CI 1999–2001), Japan in 2002 (95% CI 1999–2003), and the Republic of Korea in 2007 (95% CI 2006–2008). No marked increases were seen in Malaysia, the Philippines, or Thailand. There was some evidence that charcoal-burning suicides were associated with an increase in overall suicide rates in Hong Kong, Taiwan, and Japan (for females), but not in Japan (for males), the Republic of Korea, and Singapore. Rates of change in charcoal-burning suicide rate did not differ by sex/age group in Taiwan and Hong Kong but appeared to be greatest in people aged 15–24 y in Japan and people aged 25–64 y in the Republic of Korea. The lack of specific codes for charcoal-burning suicide in the International Classification of Diseases and variations in coding practice in different countries are potential limitations of this study.

Conclusions

Charcoal-burning suicides increased markedly in some East/Southeast Asian countries (Hong Kong, Taiwan, Japan, the Republic of Korea, and Singapore) in the first decade of the 21st century, but such rises were not experienced by all countries in the region. In countries with a rise in charcoal-burning suicide rates, the timing, scale, and sex/age pattern of increases varied by country. Factors underlying these variations require further investigation, but may include differences in culture or in media portrayals of the method. Please see later in the article for the Editors'' Summary     

Navajo tribal mortality: A life table analysis of the leading causes of death

Abstract

The five leading causes of death for Navajo males and females are analyzed by life table methods. Navajo male and female life expectancy at birth were 58.8 and 71.8 years, respectively. The greatest increase in Navajo male life expectancy would result from the elimination of motor vehicle accidents (5.17 years at birth, and 3.11 years for working ages 15–65). The life expectancy of Navajo females would be lengthened the most (3.70 years) by elimination of circulatory system disease. For working‐ages gains for both sexes, however, the greatest benefit would result from elimination of motor vehicle accidents. The implications of the results are discussed in relation to the various public health programs and health planning efforts for the Navajo Nation.     

Assessing the contribution of age-sex differentials in causes of death due to infectious and parasitic diseases to the trends in age-sex differentials in life expectancy in Mauritius

This study applies two methodologies to Mauritian life tables and cause-of-death data: (1) the decomposition of sex differentials in life expectancy using Arriaga's approach and (2) the estimation of the effect of marginal reduction in deaths from infectious and parasitic diseases on life expectancy using Keyfitz's methodology on cause-specific entropy and that of Nanjo. The findings in this paper support earlier findings about the importance of the period 1969-1976 in the mortality transition in Mauritius, a period in which sex differentials in life expectancies reached a peak level. The results suggest that the driving force behind those sex differentials in life expectancy was the sex differential in mortality in infectious and parasitic diseases, first among the young (ages below 10 years) and second among the older population (ages above 50 years). If the decline in mortality due to infectious and parasitic diseases was differentially greater in the older ages compared to the younger ages, that difference would have gone a long way toward reducing the magnitude of the historic peak sex differential in life expectancy achieved in 1976.     

Life Expectancy and the Timing of Life History Events in Developing Countries

Life history theory predicts that greater extrinsic mortality will lead to earlier and higher fertility. To test this prediction, I examine the relationship between life expectancy at birth and several proxies for life history traits (ages at first sex and first marriage, total fertility rate, and ideal number of children), measured for both men and women. Data on sexual behaviors come from the Demographic and Health Surveys (DHS). Two separate samples are analyzed: a cross-sectional sample of 62 countries and a panel sample that includes multiple cross-sectional panels from 48 countries. Multivariate regression analysis is used to control for potential confounding variables. The results provide only partial support for the predictions, with greater support among women than men. However, the prediction is not supported in sub-Saharan African countries, most likely owing to the nonequilibrium conditions observed in sub-Saharan Africa with respect to life expectancy. The applicability of the model to understanding HIV/AIDS risk behaviors is discussed.     

Hypothesis: the reversal of the relation between economic growth and health progress in Sweden in the nineteenth and twentieth centuries was caused by electrification

The expected decline of health indicators with economic recessions and improvement with economic growth in the nineteenth century Sweden was reversed in the twentieth century, giving the counterintuitive pattern of higher mortality and lower life expectancy in economic expansions and improvement of these indices in recessions. The change or “tipping point” occurred at the end of the nineteenth century or early in the twentieth century when electrification was introduced into Sweden. All 5 of the reversals of annual industrial electric energy use in the US between 1912 and 1970 were accompanied by recessions with lowered GDP, increased unemployment, decreased mortality and increased life expectancy. The health indices were not related to residential electricity use. The mortality improvement between 1931 and 1932 by state in the US strongly favored urban areas over rural areas. Rural unemployment by state in 1930 was significantly positively correlated with residential electrification percentage by state in 1930. The health effects of economic change are mediated by electrical exposure.     

Demographic and health patterns in a rural community from the Basque area in Spain (1800-1990)

In this work, the evolution of demographic and health patterns in a Basque rural population from Spain is analysed, as they relate to progress in demographic and epidemiological transition. For this purpose, parochial record data on 13,298 births and 9,215 deaths, registered during the 19th and 20th centuries (1800-1990), were examined. The study area is a rural community called Lanciego, which is located at the southern end of the Rioja Alavesa area (Alava Province, Basque Country). In Lanciego, demographic transition began in the final decade of the 19th century, when a definite, irreversible trend began towards a reduction in mortality. The decrease in the birth rate came later than that in the death rate, and did not start until the 1930s. The post-transitional stage seemed to be reached in the 1970s, when the birth and death rates showed values below 20 per 1,000. Other characteristics observed for the post-transitional stage in Lanciego are: (i) very low rates of infant mortality achieved at the expense of effective control of exogenous mortality; (ii) the mortality curve by ages changes from a U-shape (typical of populations with a high infant mortality rate and low life expectancy at birth) to a J-shape more characteristic of modern societies where longevity and life expectancy are considerably higher; (iii) a certain level of over-mortality among women in the senior age group (>65); and (iv) a significant proportion of mortality in recent times (1970-90) resulting from cardiovascular diseases and malignant neoplasms (post-transition causes). This last point is in contrast with observations from the first four decades of the 20th century, when infectious diseases and respiratory ailments were determining factors in mortality among this population. The data provided by the study of the variation over time in demographic and health patterns indicate that reducing the risk of mortality is one of the most important preconditions for fertility decline.     

The Signs of Economic Disparity in Russia Following the Implosion of the USSR

For untold centuries social stratification has been a feature of human societies, forming, as George Orwell put it, a payment for civilization. The continuing relevance of the topic arises from the fact that, being inevitable, stratification has generated and still generates various negative social effects: an increase in crime and mortality, a decline in life expectancy, and much more. An American researcher calculated that in 1990, in the USA, social inequality claimed more lives than HIV, lung cancer, diabetes and road accidents combined. Also in the UK each winter, about 20,000 people die from illness exacerbated by not being able to afford to pay for heating. In this article, the authors explore the state of social equality in the Soviet and post-Soviet period throughout the territory of the Russian Federation.     

Sex and Life Expectancy

BackgroundA sexual dimorphism in human life expectancy has existed in almost every country for as long as records have been kept. Although human life expectancy has increased each year, females still live longer, on average, than males. Undoubtedly, the reasons for the sex gap in life expectancy are multifaceted, and it has been discussed from both sociological and biological perspectives. However, even if biological factors make up only a small percentage of the determinants of the sex difference in this phenomenon, parity in average life expectancy should not be anticipated.ObjectiveThe aim of this review is to highlight biological mechanisms that may underlie the sexual dimorphism in life expectancy.MethodsUsing PubMed, ISI Web of Knowledge, and Google Scholar, as well as cited and citing reference histories of articles through August 2012, English-language articles were identified, read, and synthesized into categories that could account for biological sex differences in human life expectancy.ResultsThe examination of biological mechanisms accounting for the female-based advantage in human life expectancy has been an active area of inquiry; however, it is still difficult to prove the relative importance of any 1 factor. Nonetheless, biological differences between the sexes do exist and include differences in genetic and physiological factors such as progressive skewing of X chromosome inactivation, telomere attrition, mitochondrial inheritance, hormonal and cellular responses to stress, immune function, and metabolic substrate handling among others. These factors may account for at least a part of the female advantage in human life expectancy.ConclusionsDespite noted gaps in sex equality, higher body fat percentages and lower physical activity levels globally at all ages, a sex-based gap in life expectancy exists in nearly every country for which data exist. There are several biological mechanisms that may contribute to explaining why females live longer than men on average, but the complexity of the human life experience makes research examining the contribution of any single factor for the female advantage difficult. However, this information may still prove important to the development of strategies for healthy aging in both sexes.