Contemporaneous Mortality Research Articles

Public unemployment relief and health during the great depression

ABSTRACT This paper uses newly collected data on county-level unemployment relief recipiency in 1933 with an OLS with fixed effects and a cross-sectional border-county research design, to examine the correlation between Depression-era public assistance and contemporaneous mortality. The paper finds that in counties where the government tended to support more unemployed families, mortality was lower, particularly for white families. Overall, the unemployment relief program accounted for around 2.5 percentage points of the mortality decline. This cross-sectional finding, is robust to a range of specifications, including an instrument variable design. The largest mortality reductions came from drops in communicable and infectious diseases.

How safe bariatric surgery is-An update on perioperative mortality for clinicians and patients.

Bariatric, metabolic or weight loss surgery produces sustained weight loss and imporovement in obesity related diseases. Bariatric surgery has existed for decades but there is limited reliable data on the risk of perioperative mortality following the procedures. This commentary focuses on a recent meta-analysis which has produced contemporaneous mortality data, and the findings are significant. Utilising data from 3.6 million patients the study has shown an overall pooled perioperative mortality of 0.08%, a significantly reduced risk compared to previous, smaller studies. This finding increases our knowledge of surgical risk for these procedures and should now equip health care groups to challenge barriers to uptake of bariatric surgery. Barriers currently include a worldwide lack of focus on treating obesity, lack of funding and resource from commissioners, and a general public and professional view that bariatric surgery may be high risk. In reality, this figure equates to mortality risk for procedures generally considered 'safe' such as laparoscopic cholecystectomy and knee arthroplasty. Bariatric surgery is a safe option for achieving sustained weight-loss and the treatment of obesity related diseases, and refusing access to surgery on the grounds of perioperative safety should now be an outdated premise.

DID EARLY TWENTIETH‐CENTURY ALCOHOL PROHIBITION AFFECT MORTALITY?

We investigate the contemporaneous mortality consequences of alcohol prohibition laws introduced in America between 1900 and 1920. We improve on existing studies by constructing a time‐varying measure of prohibition at the state level that corrects for the timing of prohibition enforcement and accounts for the presence of dry counties. Using summary indices that aggregate alcohol‐related mortality due to disease and poor decisions, we find that prohibition significantly reduced mortality rates. These findings are corroborated with an area‐level analysis that exploits data on deaths in urban areas that were wet prior to statewide or federal prohibition and nonurban areas that were partially dry. (JEL I18, N4, K2)

Did Early Twentieth Century Alcohol Prohibition Matter?

We investigate the contemporaneous mortality consequences of alcohol prohibition laws introduced in America between 1900 and 1920. We improve on existing studies by constructing a time-varying measure of prohibition at the state-level that corrects for the timing of prohibition enforcement and accounts for the presence of dry counties. Using summary indices that aggregate alcohol-related mortality due to disease and poor decisions, we find that prohibition significantly reduced mortality rates. These findings are corroborated with an area-level analysis that exploits data on deaths in urban areas that were wet prior to statewide or federal prohibition and non-urban areas that were partially dry.

Two species of egg parasites as contemporaneous mortality factors in the egg population of the southern green stink bug, Nezara viridula

Two species of egg parasites as contemporaneous mortality factors in the egg population of the southern green stink bug, Nezara viridula

Bacterial Genomics Reveal the Complex Epidemiology of an Emerging Pathogen in Arctic and Boreal Ungulates.

Northern ecosystems are currently experiencing unprecedented ecological change, largely driven by a rapidly changing climate. Pathogen range expansion, and emergence and altered patterns of infectious disease, are increasingly reported in wildlife at high latitudes. Understanding the causes and consequences of shifting pathogen diversity and host-pathogen interactions in these ecosystems is important for wildlife conservation, and for indigenous populations that depend on wildlife. Among the key questions are whether disease events are associated with endemic or recently introduced pathogens, and whether emerging strains are spreading throughout the region. In this study, we used a phylogenomic approach to address these questions of pathogen endemicity and spread for Erysipelothrix rhusiopathiae, an opportunistic multi-host bacterial pathogen associated with recent mortalities in arctic and boreal ungulate populations in North America. We isolated E. rhusiopathiae from carcasses associated with large-scale die-offs of muskoxen in the Canadian Arctic Archipelago, and from contemporaneous mortality events and/or population declines among muskoxen in northwestern Alaska and caribou and moose in western Canada. Bacterial genomic diversity differed markedly among these locations; minimal divergence was present among isolates from muskoxen in the Canadian Arctic, while in caribou and moose populations, strains from highly divergent clades were isolated from the same location, or even from within a single carcass. These results indicate that mortalities among northern ungulates are not associated with a single emerging strain of E. rhusiopathiae, and that alternate hypotheses need to be explored. Our study illustrates the value and limitations of bacterial genomic data for discriminating between ecological hypotheses of disease emergence, and highlights the importance of studying emerging pathogens within the broader context of environmental and host factors.

Recessions, Older Workers, and Longevity: How Long Are Recessions Good for Your Health?

Although past research has found that recessions reduce contemporaneous mortality, workers nearing retirement age may experience reduced longevity attributable to lengthy unemployment spells and lost health insurance at a particularly vulnerable time. To test this hypothesis, we generate age-specific cohort survival probabilities using 1965–2008 Vital Statistics mortality data and link them to labor market conditions at earlier ages. Our results indicate that experiencing a recession in one's late 50s reduces longevity. We also find that it leads to several years of reduced employment, health insurance coverage, and health care utilization, which may contribute to the lower long-term likelihood of survival. (JEL E32, I12, I13, J14, J26)

Irreplaceable Mortality: Is It?

Peterson et al. (2009) presented an analysis of mortality rates of herbivorous insects using published life tables. For each mortality factor in each life table, they estimated the marginal attack rate (hereinafter, “marginal mortality rate”), i.e., the mortality rate expected in the absence of contemporaneous mortality factors assuming independence of occurrence and making some assumption concerning the outcome of their joint occurrence. Using these marginal mortalities, they calculated rates of irreplaceable mortality (“indispensable mortality”, Southwood 1978), i.e., the decrease in total mortality when a given mortality factor or group of factors is excluded from the life table. They compared irreplaceable mortalities for six categories of factors and found that irreplaceable mortality because of non-natural enemies (primarily abiotic factors) was significantly higher than that because of natural enemies. Characterizing irreplaceable mortality because of natural enemies as “very low”, they concluded that natural enemies typically have little impact on insect populations at temperate latitudes and in agricultural systems. They suggested that the impact of natural enemies may be higher in ecosystems with higher stability. They also presented an example based on Kuhar et al. (2002) of using irreplaceable mortality to assess the value of biological control agents. Unfortunately, problems with estimation and application of irreplaceable mortality weaken or invalidate their conclusions. It is important to consider proper usage of irreplaceable mortality because its misuse can result in misleading generalizations concerning insect ecology and in poor pest management decisions. ### Irreplaceable Mortality: Suitable Measure of the Effect of Mortality Factors on Population Growth Rate? Peterson et al. (2009) used irreplaceable mortality as a measure of the effect of mortality factors on population growth rate in comparisons among life tables. However, as pointed out by Bellows and Van Driesche (1999) and discussed in this section, irreplaceable mortality is generally inappropriate for such comparisons. For discrete generations, population growth rate is measured as the net multiplication rate per generation ( R …

International correlations between indicators of prevalence, hospital admissions and mortality for asthma in children

There are extensive data on the prevalence of childhood asthma world-wide but the relationships between asthma symptom prevalence, mortality and hospital admissions have not been investigated. The International Study of Asthma and Allergies in Childhood (ISAAC) used a standard questionnaire to measure the 12-month period prevalence of asthma symptoms by parental report in 6-7 year olds in 40 countries, and by self-report in 13-14 year olds in 60 countries. The initial survey was in the mid 1990s (Phase One) and this was repeated in the early 2000s (Phase Three). We correlated the prevalence values of any wheeze and severe wheeze with national data on mortality and hospital admissions for asthma in 5-14 year olds. All correlations with prevalence were positive. In 13-14 year olds, the correlations between severe wheeze in Phase One and contemporaneous mortality and hospital admission rates were r = 0.32 (P = 0.047) and r = 0.73 (P = 0.003), respectively. In 6-7 year olds in Phase One, the correlation with severe wheeze and mortality was r = 0.42 (P = 0.024). In 14 countries the correlation between admission and mortality rates in the 5-14 year age group was r = 0.53 (P = 0.054). There are consistently positive associations between asthma symptom prevalence, admissions and mortality. The prevalence of asthma symptoms in children obtained from local questionnaire studies may provide a guide to estimate the incidence of severe episodes of asthma in countries with incomplete data on hospital admissions or mortality, or vice versa.

Aerosol Research and Inhalation Epidemiological Study (ARIES): Air Quality and Daily Mortality Statistical Modeling— Interim Results

ABSTRACT The Aerosol Research and Inhalation Epidemiological Study (ARIES) is an EPRI-sponsored project to collect air quality and meteorological data at a single site in northwestern Atlanta, GA. Seventy high-resolution air quality indicators (AQIs) are used to examine statistical relationships between air quality and health outcome end points. Contemporaneous mortality data are collected for Fulton and DeKalb counties in Georgia. Currently, 12 months of air quality and weather data are available for analysis, from August 1998 through July 1999. The interim mortality analysis used Poisson regression in generalized additive models (GAMs). The estimated log-linear association of mortality with various AQIs was adjusted for smoothed functions of time and meteorological data. The analysis considered daily deaths due to all nonaccidental causes, deaths to persons 65 years or older, and deaths in each of the two constituent counties. The fine particle effect associated with the four mortality subgroups, using only today (lag 0), yesterday (lag 1), 2-day average (average of today and yesterday), and first difference (today minus yesterday) measurements of the air quality relative to today's number of deaths was positive for lag 0, lag 1, and 2-day average and positive only for decedents at least 65 years of age using first difference. The t values ranged from 0.81 to 1.15 for lag 0, 1.04 to 1.53 for lag 1, 1.10 to 1.66 for 2-day average, and -0.32 to 0.33 for first difference with 346 or 347 days of data. No statistically significant estimate of the linear coefficient was found for the other 14 air quality variables in our interim analysis for the four mortality subgroups. We discuss diagnostics to support these models. These interim analyses did not include an evaluation of sensitivity to a larger set of lag structures, nonlinear model specifications, multipollutant analyses, alternative weather model and smoothing model specifications, air pollution imputation schemes, or cause-specific mortality indicators, nor did they include a full reporting of model selection or goodness-of-fit indicators. No conclusion can be drawn at this time about whether the findings from subsequent studies have sufficiently greater power to detect effects comparable to those found in other U.S. cities including at least 2 or 3 years of data.

Marginal attack rate, k‐values and density dependence in the analysis of contemporaneous mortality factors

Summary Procedures for calculating the marginal attack rates and associated k‐values from observed death rates are presented for contemporaneous predators or parasitoids that either do or do not discriminate against previously parasitized hosts. The relationships among previous methods for quantifying contemporaneous mortalities are discussed. Solutions to the problem of calculating marginal rates taken from human survival analysis are given under the assumption of proportional hazards. These calculations are easily extended to three or more contemporaneous sources of mortality. The conditions under which proportional hazards can be expected are discussed. These methods are compared to that of Varley et al., 1973 for assessment of density dependence among contemporaneous predators.

Estimation of contemporaneous mortality factors

SummaryWe present methods for solving and making statistical inferences about marginal attack rates based on observed death rates for contemporaneous mortality factors. The general method of solution involves solving a system of nonlinear equations which depend in part on competition coefficients that express the outcome when more than one agent attacks the same host individual. For two factors, we present a detailed analysis of the effect of varying this competition coefficient. Statistical inferences are illustrated using standard large sample approximations (the delta method) and the bootstrap, which is a resampling technique. We also extend the results to allow inferences for k‐values.

Evaluation of Mortality Factors in Insect Life Table Analysis

An individual animal may suffer simultaneously from several different maladies, which lead to its eventual death. Such "overlaps" between contemporaneous mortality factors create some problems in partitioning, in a consistent manner, the animals killed among several specific causes. The aim of this paper is to develop the notion of "killing power" of a mortality factor, so that we can properly evaluate and incorporate in a model the effect of any given factor on the dynamics of the animal population concerned. I first introduce the basic notion of killing power under the assumption that the mortality factors involved are operating independently of each other. The killing power of a given factor is then shown to be equivalent to the marginal probability of an animal being killed by that factor. The assumption of independence of the mortality factors is relaxed, and the more general notion of conditional killing power is introduced. This is equivalent to the conditional probability of an animal being killed by a given mortality factor, when that individual has not been simultaneously affected by other contemporaneous factors. The concept of mutually exclusive mortality factors is discussed to clarify an apparent confusion in some published literature. Typical examples of this type of mortality factor are an extended drought and excessively wet weather, both of which may kill some animals, but which will not occur simultaneously. Therefore, unless the stage division in the life tables so broad that these types of factors can occur in the same stage, we do not need to consider mutually exclusive mortality factors. How to evaluate the killing power of a mortality factor is illustrated with some examples taken from the literature. Also discussed is a more complicated case, in which the annual fluctuation in the proportion of animals killed by a given factor is correlated with those killed by other contemporaneous mortality factors. Concluding remarks include some notes on the division of stages in a life table so as to facilitate the evaluation of the killing powers of as many mortality factors as possible.

Contemporaneous Mortality Factors in Population Dynamics

AbstractThe effect of any mortality factor on population trend is influenced greatly by other factors that operate contemporaneously within the same age interval, and by the extent to which it interacts with these other factors. A general equation which makes provision for different degrees of interaction is proposed as a simplified first step in the study of interaction, and some theoretical examples are presented to illustrate the importance of the interaction coefficient. Methods for obtaining estimates of the coefficient, both through statistical inference from field population data and through direct observation and experimentation, are discussed.