CESAREAN SECTION EXPERIENCE AT THE UNIVERSITY OF CALIFORNIA HOSPITAL

A review of the 746 cesarean sections performed at the University of California Hospital from 1907 through 1948 shows an overall cesarean section incidence of 3.91 per cent. The maternal mortality rate associated with these cesarean sections has been 1.61 per cent. There has been a steady decline in mortality over the 40-year period and there have been no deaths from cesarean section in the last ten years. The over-all incidence of morbidity associated with cesarean section has been 40.5 per cent and again there has been a significant improvement in recent years. The fetal mortality associated with cesarean section has been 6.1 per cent. In view of recent experience, standards based on figures collected 20 years ago are no longer tenable.     

Divergent Paths for Adult Mortality in Russia and Central Asia: Evidence from Kyrgyzstan

Adult mortality has been lower in Kyrgyzstan vs. Russia among males since at least 1981 and among females since 1999. Also, Kyrgyzstan’s mortality fluctuations have had smaller amplitude. This has occurred in spite of worse macro-economic outcomes in Kyrgyzstan. To understand these surprising patterns, we analyzed cause-specific mortality in Kyrgyzstan vs. Russia for the period 1981-2010, using unpublished official data. We find that, as in Russia, fluctuations in Kyrgyzstan have been primarily due to changes in external causes and circulatory causes, and alcohol appears to play an important role. However, in contrast with Russia, mortality from these causes in Kyrgyzstan has been lower and has increased by a smaller amount. As a result, the mortality gap between the two countries is overwhelmingly attributable to external and cardio-vascular causes, and more generally, to causes that have been shown to be strongly related to alcohol consumption. These cause-specific results, together with the existence of large ethnic differentials in mortality in Kyrgyzstan, highlight the importance of cultural and religious differences, and their impact on patterns of alcohol consumption, in explaining the mortality gap between the two countries. These findings show that explanatory frameworks relying solely on macro-economic factors are not sufficient for understanding differences in mortality levels and trends among former Soviet republics.     

Objectively Measured Daily Steps and Subsequent Long Term All-Cause Mortality: The Tasped Prospective Cohort Study

BackgroundSelf–reported physical activity has been inversely associated with mortality but the effect of objectively measured step activity on mortality has never been evaluated. The objective is to determine the prospective association of daily step activity on mortality among free-living adults.ConclusionsHigher daily step count was linearly associated with subsequent long term mortality among free living adults. These data are the first to quantify mortality reductions using an objective measure of physical activity in a free living population. They strongly underscore the importance of physical inactivity as a major public health problem.     

Markov mortality models: implications of quasistationarity and varying initial distributions

This paper explains some implications of Markov-process theory for models of mortality. We show that an important qualitative feature common to empirical mortality data, and which has been found in certain models-the convergence to a "mortality plateau"-is, in fact, a generic consequence of the models' convergence to a "quasistationary distribution". This phenomenon has been explored extensively in the mathematical literature. Not only does this generalization free important results from specifics of the models, it also suggests a new explanation for the convergence to constant mortality. At the same time that we show that the late behavior of these models-convergence to a finite asymptote-is almost logically immutable, we also point out that the early behavior of the mortality rates can be more flexible than has been generally acknowledged. We show, in particular, that an appropriate choice of initial conditions enables one popular model to approximate any reasonable hazard-rate data. This illustrates how precarious it can be to read a model's vindication from its consilience with a favored hazard-rate function, such as the Gompertz exponential.     

A general measure of human population growth regulation

A general measure relating the relative effects of mortality and fertility in damping population growth has been derived from stable population theory. This measure, called the Index of Growth Regulation, can be calculated from a life table and a fertility schedule. It is a single number which integrates the fertility and mortality aspects of a population. It has intuitive meaning, and can be related to social aspects of the population. It can be used to compare any two populations, and for this purpose it has advantages over traditional comparative statistics such as life expectancy, which consider only mortality. By selecting life tables representing general stages of human cultural evolution, it has been shown that hunting-gathering populations were regulated more by mortality than by fertility factors. That is, more growth which could have occurred did not occur due to the incidence of mortality than to the incidence of infecundity. The two forces were of about equal weight before the industrial revolution, and fertility has had a predominant role in population regulation since the beginning of industrialization.     

The remarkable improvements in survival at older ages.

The belief that old-age mortality is intractable remains deeply held by many people. Remarkable progress, however, has been made since 1950, and especially since 1970, in substantially improving survival at older ages, even the most advanced ages. The pace of mortality improvement at older ages continues to be particularly rapid in Japan, even though mortality levels in Japan are lower than elsewhere. The progress in improving survival has accelerated the growth of the population of older people and has advanced the frontier of human survival substantially beyond the extremes of longevity attained in pre-industrial times. Little, however, is known about why mortality among the oldest-old has been so plastic since 1950. The little that is known has largely been learned within the past few years. New findings, especially concerning genetic factors that influence longevity, are emerging at accelerating rate.     

Secular trend in neonatal mortality in the moutain states

Reviewing trends in neonatal mortality from 1957 to 1967, it is clear that neonatal and infant mortality has declined faster in the mountain states than in the low altitude states. Accordingly, the increased neonatal and infant mortality at high altitudes or in the mountain states cannot be attributed to high altitude hypoxia alone. Furthermore, the decline in neonatal mortality in the mountain states has not been accompanied by a decrease in the frequency of low birth weight (below 2500 gm) and is therefore not a product of increasing body size in the neonate.     

Differential mortality in Turkana agriculturalists and pastoralists

Nomadic pastoral populations appear to have much lower rates of growth than the otherwise very high growth rates now characteristic of populations in developing nations. Because dramatic declines in infant mortality have been a primary contributor to increased population growth rates in these countries, it has been assumed that nomadic pastoral populations are still characterized by high levels of mortality in the first few years of life. Few studies, however, have been undertaken to estimate demographic parameters for nomadic pastoral populations, and even fewer of a comparative nature have been undertaken to document the impact of subsistence strategy on demographic processes. This study compares indirect childhood mortality estimates for Turkana nomadic pastoralists with childhood mortality in a settled agricultural group within the same population and finds that pastoralists have substantially higher levels of mortality. Based on the childhood mortality estimates, model life tables are selected for pastoral and agricultural groups from which values for mean life expectancy and infant mortality are estimated and compared. Recent improvements in primary health care for the settled agricultural group are ruled out as being an important cause of their lower mortality levels, and some aspects of life-style associated with subsistence strategy are discussed as likely determinants of the mortality differences.     

Monitoring the decreasing trend of testicular cancer mortality in Spain during 2005–2019 through a Bayesian approach

Purpose: To assess time trends of testicular cancer (TC) mortality in Spain for period 1985–2019 for age groups 15–74 years old through a Bayesian age–period–cohort (APC) analysis. Methods: A Bayesian age–drift model has been fitted to describe trends. Projections for 2005–2019 have been calculated by means of an autoregressive APC model. Prior precision for these parameters has been selected through evaluation of an adaptive precision parameter and 95% credible intervals (95% CRI) have been obtained for each model parameter. Results: A decrease of ?2.41% (95% CRI: ?3.65%; ?1.13%) per year has been found for TC mortality rates in age groups 15–74 during 1985–2004, whereas mortality showed a lower annual decrease when data was restricted to age groups 15–54 (?1.18%; 95% CRI: ?2.60%; ?0.31%). During 2005–2019 is expected a decrease of TC mortality of 2.30% per year for men younger than 35, whereas a leveling off for TC mortality rates is expected for men older than 35. Conclusions: A Bayesian approach should be recommended to describe and project time trends for those diseases with low number of cases. Through this model it has been assessed that management of TC and advances in therapy led to decreasing trend of TC mortality during the period 1985–2004, whereas a leveling off for these trends can be considered during 2005–2019 among men older than 35.     

The effects of extra chances to live on life table functions

A decline in mortality can be described as a process according to which the earlier forces of mortality become what has been defined here as the forces of debility. The main thesis is that individuals contract debilitating conditions now with the same force that used to result in deaths in the past. The difference in the two situations is that in the latter period, a certain proportion of the population can recover and thus escape death. Based on these assumptions, the relationships between the initial and the resulting life table functions have been developed in this paper. Among other things, the relative gain in life expectancy has been found to be inversely related to its initial value. Further, interesting results are obtained when a fixed proportion of the population can manage to survive a debilitating condition only once, only twice and so on. The limiting situation has been found to be equivalent to one in which the initial forces of mortality at all ages are reduced by a constant proportion.     

Developing a Social Autopsy Tool for Dengue Mortality: A Pilot Study

BackgroundDengue fever is a public health problem in the tropical and sub-tropical world. Dengue cases have grown dramatically in recent years as well as dengue mortality. Colombia has experienced periodic dengue outbreaks with numerous dengue related-deaths, where the Santander department has been particularly affected. Although social determinants of health (SDH) shape health outcomes, including mortality, it is not yet understood how these affect dengue mortality. The aim of this pilot study was to develop and pre-test a social autopsy (SA) tool for dengue mortality.ConclusionsThe SA tool is based on the scientific literature, a validated conceptual framework, researchers’ and health professionals’ expertise, and a pilot study. It is the first time that a SA tool has been created for the dengue mortality context. Our work furthers the study on SDH and how these are applied to neglected tropical diseases, like dengue. This tool could be integrated in surveillance systems to provide complementary information on the modifiable and avoidable death-related factors and therefore, be able to formulate interventions for dengue mortality reduction.     

A linear mixed model to estimate COVID-19-induced excess mortality

The Corona Virus Disease (COVID-19) pandemic has increased mortality in countries worldwide. To evaluate the impact of the pandemic on mortality, the use of excess mortality rather than reported COVID-19 deaths has been suggested. Excess mortality, however, requires estimation of mortality under nonpandemic conditions. Although many methods exist to forecast mortality, they are either complex to apply, require many sources of information, ignore serial correlation, and/or are influenced by historical excess mortality. We propose a linear mixed model that is easy to apply, requires only historical mortality data, allows for serial correlation, and down-weighs the influence of historical excess mortality. Appropriateness of the linear mixed model is evaluated with fit statistics and forecasting accuracy measures for Belgium and the Netherlands. Unlike the commonly used 5-year weekly average, the linear mixed model is forecasting the year-specific mortality, and as a result improves the estimation of excess mortality for Belgium and the Netherlands.     

Reports of the Death of Extrinsic Mortality Moulding Senescence Have Been Greatly Exaggerated

The classic evolutionary theory of aging posits that senescence evolves because the weakening of selection with age allows mutations with late-acting deleterious effects to accumulate. Because extrinsic mortality is an important cause of weakening selection, the central prediction of the theory has been that higher extrinsic mortality should lead to the evolution of a higher rate of senescence. However, the validity of this prediction has been questioned, even to the extent of suggesting that it is not a prediction of the theory at all, primarily on the basis that changes in population growth rate will compensate for changes in extrinsic mortality. The implication is that empiricists have been using the wrong prediction to test the theory. This claim is misleading, however, because it does not apply on an evolutionary timescale, when population size must be roughly constant. With a constant population size, Hamilton’s fitness sensitivities show that extrinsic mortality determines the rate at which the strength of selection declines with age, and thus determines the rate of senescence. The central prediction has been confirmed in the few controlled experiments with model organisms that have been conducted, but clearly this is an area ripe for further investigation.     

The correlation of the indices of animal longevity and mortality in stationary populations with a constant rate of mortality

Equations have been derived on the basis of general ratios of the numbers of different age groups of animals that allow to estimate the mortality coefficient in populations with stationary age structure and intensity of mortality that does not depend on age at their continuous and discontinuous replenishing by frequency of occurrence of individuals of the maximal age. The proposed method of estimation of mortality has been tested on models with different numbers of animals and age classes. The equation gives a non-biased estimate of mortality coefficient for populations with discontinuous replenishing with young individuals at very small sample sizes (less than 10 individuals).     

Island mortality in the past: some evidence from Greece

This paper explores the course of infant and childhood mortality in the Greek island of Paros from the end of the nineteenth until the mid-twentieth century. For this purpose the method of family reconstitution has been applied to two towns on the island. Official population statistics have been used to derive basic mortality estimates for the Cyclades and Greece as a whole. Reference to other studies concerning island mortality is also made. Hence, there appears the chance to compare insular with mainland mortality and realise that insular mortality presented some distinct features. It is shown that island populations presented lower mortality than the national average until the first decades of the twentieth century. However, by the 1950s Greece's infant and childhood mortality had dropped to the same or even to lower levels than those of the islands.     

The potentiation of ammonia toxicity by sodium benzoate is prevented by L-carnitine

Sodium benzoate has been recommended and even been used for the treatment of hyperammonemia in humans. More recently, a note of caution was raised since it has been shown that in experimental animals, sodium benzoate potentiates ammonia toxicity and inhibits urea synthesis in vitro. This has been further confirmed in the work presented here and the mechanism by which benzoate increases mortality and the levels of blood ammonia in mice given ammonium acetate have also been studied. In hyperammonemia, urea production and N-acetylglutamate levels were decreased by sodium benzoate. Pretreatment of mice with L-carnitine suppressed mortality following ammonium acetate plus sodium benzoate administration. Under these conditions L-carnitine lowered blood ammonia and increased urea production and N-acetylglutamate levels.     

Neighbour-regulated mortality: the influence of positive and negative density dependence on tree populations in species-rich tropical forests

Density‐dependent mortality has long been posited as a possible mechanism for the regulation of tropical forest tree density. Despite numerous experimental and phenomenological investigations, the extent to which such mechanisms operate in tropical forests remains unresolved because the demographical signature of density dependence has rarely been found in extensive investigations of established trees. This study used an individual‐based demographical approach to investigate the role of conspecific and heterospecific neighbourhood crowding on tree mortality in a Panamanian and a Malayan tropical forest. More than 80% of the species investigated at each site were found to exhibit density‐dependent mortality. Furthermore, most of these species showed patterns of mortality consistent with the Janzen–Connell hypothesis and the rarely explored hypothesis of species herd protection. This study presents some of the first evidence of species herd protection operating in tree communities.     

The Epidemiology of Cerebral Vascular Disease in Canada: An Analysis of Mortality Data

Mortality data for cerebral vascular disease in Canada and its provinces were analysed as an initial approach to the understanding of the epidemiology of this disease. Since 1950, there has been a decline in mortality attributed to vascular lesions of the central nervous system. This decline has been more pronounced in females. Five-year average age-sex-specific rates (1960-64) showed an almost constant proportional increase with age. The highest mortality rates tended to occur in the Eastern Provinces.From 1950 to 1964 there was a 21% decline in mortality due to intracranial hemorrhage and a concomitant 53% decline in mortality attributed to hypertensive disease. Over the same period there was a 24% increase in mortality attributed to cerebral embolism and thrombosis, and an 8% increase in mortality due to arteriosclerotic heart disease. Areal correlations offered only inconsistent support for the hypothesis that these associated trends are due to common etiologic determinants.Evidence presently available does little to clarify to what extent these trends and differences can be attributed to coding, certification and diagnostic practices, and to what extent to changing and differing incidence and prognosis.     

Child mortality and malaria transmission intensity in Africa

The desirability of controlling malaria transmission in the areas of highest endemicity of Plasmodium falciparum has long been debated. Most recently, it has been claimed that rates of malaria morbidity are no higher in areas of very high transmission in Africa than they are in places with lower inoculation rates. We now review the literature on the relationship of morbidity and mortality to malaria transmission intensity, and have linked published child mortality and malaria transmission rates to examine how age-specific mortality actually varies with the inoculation rate of P. falciparum.     

Incidence of ecological factors on the evolution of infant mortality in a Mediterranean population (La Alpujarra,SE Spain)

The infant mortality evolution in the present century has been analyzed in a rural Mediterranean population (La Alpujarra, SE Spain). The “conventional infant mortality rate” shows a decrease from 184.82, in 1900–1904, to 25.16, in 1975–1978. The sexual proportion for all period studied indicates a male supermortality about 1.13. The biometric analysis reveals an excess of exogenous mortality at the first half of the century, attributed to digestive problems, as has been found in other Mediterranean populations. The seasonal distribution presents an evolutionary change from a maximum in estival months to a maximum in winter ones.