Timothy B Gage

University at Albany, The State University of New York | UAlbany · Center for Social and Demographic Analysis

Objective: In the developmental programming literature, the association of birth weight and blood pressure later in life is modest at best. This article reexamines this issue using Covariate Density Defined mixture of regressions (CDDmr) to determine if a latent variable, based on birth weight, and known to influence infant mortality, provides a s...

To determine if a small body size at birth is associated with an unfavorable metabolic profile and a reduced response to exercise training in young adults. Thirty-six college students, all singletons born to term, participated. Subjects were defined as either high ponderal index (HIGHPI) or low ponderal index (LOWPI). LOWPI was defined as below the...

Poor fetal growth is associated with later-life changes in adult body composition and decrements in muscle strength and morphology. Few studies have investigated the association of poor fetal growth with whole-body exercise. The purpose of this study was to investigate the association of poor fetal growth with the maximal oxygen consumption (VO2max...

This research determines whether the observed decline in infant mortality with socioeconomic level, operationalized as maternal education (dichotomized as college or more, versus high school or less), is due to its "indirect" effect (operating through birth weight) and/or to its "direct" effect (independent of birth weight). The data used are the 2...

Poor fetal growth is associated with decrements in muscle strength likely due to changes during myogenesis. We investigated the association of poor fetal growth with muscle strength, fatigue resistance, and the response to training in the isolated quadriceps femoris. Females (20.6 years) born to term but below the 10th percentile of ponderal index...

It has been hypothesized that birth weight is not on the causal pathway to infant mortality, at least among "normal" births (i.e. those located in the central part of the birth weight distribution), and that US racial disparities (African American versus European American) may be underestimated. Here these hypotheses are tested by examining the rol...

Measures of Mortality and FertilityPopulation Theories: The Basis for Indirect EstimationAge EstimationModels of Age-Specific Vital RatesComplete Indirect Methods Applicable to Archaeological DataSome Remaining IssuesConclusions AcknowledgmentsReferences

We examine the associations between nutrition and mortality at the national level. Altogether four aspects of this association are explored: (1) total calories with expectation of life, (2) dietary composition with expectation of life, (3) total calories with the age patterns of mortality, and (4) dietary composition with the age patterns of mortal...

Fryer et al. (1984), Gage and Therriault (1998), and Gage (2000) show that a two-component Gaussian mixture model describes the birth-weight distribution very well and gestational age distribution reasonably well. This finding led to the hypothesis that one of the subpopulations, the subpopulation that accounted for low-birth-weight and high-birth-...

The Agricultural Revolution accompanied, either as a cause or as an effect, important changes in human demographic systems. The consensus model is that fertility and mortality increased and health declined with the adoption of agriculture, compared to those for hunter-gatherers. Analysis of the agricultural transition relies primarily on archaeolog...

Classifications such as low birth weight, premature, and small for gestational age. i.e. compromised births, have been criticized because they depend upon arbitrary standards that may not be appropriate for all populations. This study applies multivariate Gaussian mixture models with covariates to characterize birth weight by gestational age distri...

It has been argued (e.g., the Wilcox-Russell hypothesis) that (low) birth weight is a correlate of adverse birth outcomes but is not on the "causal" pathway to infant mortality. However, the US national policy for reducing infant mortality is to reduce low birth weight. If these theoretical views are correct, lowering the rate of low birth weight m...

The "pediatric paradox" of African versus European American infant mortality is often observed with respect to birth weight, but rarely to gestational age, even though the two measures are biologically related. This paper models the pediatric paradox by birth weight and gestational age simultaneously, using Covariate Density Defined mixture of logi...

Birth weight and gestational age are both important predictors of infant survival. Covariate Density Defined mixture of logistic regressions (CDDmlr), a method that accounts for unobserved heterogeneity, has been applied to birth outcomes using birth weight alone. This paper investigates a CDDmlr model of birth outcomes that includes birth weight a...

It is a common assumption that agriculture and modernization have been detrimental for human health. The theoretical argument is that humans are adapted to hunter-gatherer lifestyles, and that the agricultural and "modern" environments are novel and hence likely to be detrimental. In particular, changes in nutrition, and population size and distrib...

This paper presents the demographic changes that followed the transition from a hunting-gathering way of life (Natufian) to an agricultural, food-producing economy (Neolithic) in the southern Levant. The study is based on 217 Natufian (10,500-8,300 BC) skeletons and 262 Neolithic (8,300-5,500 BC) skeletons. Age and sex identification were carried o...

Comparisons of birth-weight-specific infant mortality indicate that low-birth-weight African American infants have lower mortality than low-birth-weight European American infants despite higher infant mortality overall-the "pediatric paradox." One explanation is heterogeneity in birth weight. Analyses of African American and European American birth...

Several evolutionary optimal models of human plasticity in age and nutritional status at reproductive maturation are proposed and their dynamics examined. These models differ from previously published models because fertility is not assumed to be a function of body size or nutritional status. Further, the models are based on explicitly human demogr...

Researchers have traditionally employed Gaussian distributions to model quantitative biological traits. Recently, mixtures of Gaussian distributions have begun to be used as well. However, there are many alternatives to the Gaussian distribution. From a theoretical perspective, the lognormal distribution is as applicable as the Gaussian (both are j...

Birth-weight-specific infant mortality is examined using a novel statistical procedure, parametric mixtures of logistic regressions. The results indicate that birth cohorts are composed of two or more subpopulations that are heterogeneous with respect to infant mortality. One subpopulation appears to account for the "normal" process of fetal develo...

Empirical age-specific fecundity distributions are often based on small samples and hence include high levels of sampling error, particularly at the older ages. One solution to this problem is to smooth the distributions using appropriate models. The aim of this article is to compare the utility of three models for smoothing and/or graduating these...

Shared polygenic effects (i.e., pleiotropy) are assumed to exist for such obesity-related phenotypes as blood pressure and adiposity. It is possible to identify these shared genetic effects through bivariate genetic analyses. This analysis of 1,342 adult Samoans, across 801 pedigrees, indicates that significant heritable components (P < 0.05) rangi...

As an antecedent of birthweight and in its own right, gestational age is an important proximate determinant of infant mortality. Recent analyses using mixture models of birthweight distributions suggest that substantial heterogeneity occurs within a birth cohort even when controlling for sex and ethnicity. This article extends the mixture model ana...

Birth weight is the most important proximate determinant of the level of infant mortality. However, the association between birth weight and infant mortality is not constant among populations. For example, the mortality of African American infants is lower at low birth weight but higher at high birth weight compared with European American infants....

This chapter reviews the current state of knowledge concerning the demography of primates. It compiles demographic systems (mortality and fertility estimates) for four broad grades of primates: New World monkeys, Old World monkeys, chimpanzees, and humans. The characteristics of each system, including its demographic stability, are presented and di...

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Recent discoveries of early fossil hominids from the Hadar Formation in Ethiopia were interpreted as confirming "the taxonomic unity of Australopithecus afarensis and constitute the largest body of evidence for about 0.9 million years of stasis' (Kimbel et al., 1994). New clinal analyses of cranial blood flow patterns in australopithecines and new...

This study was an investigation of contraceptive switching in the context of a 5-wave panel design of diaphragm and pill users from the New York City metropolitan area. The respondents were 525 women between the ages of 14 and 46, who came to one of 10 family planning clinics to obtain birth control, Results indicated a hazard function for switchin...

The strength of the relationship between several anthropometric indicators of nutritional status, or more generally, standard of living, with overall mortality at the population level is compared. The anthropometic indicators examined include height, weight, weight-for-height, and weight-for-height2 at various ages. The results demonstrate that hei...

Mortality statistics from three captive populations of chimpanzees (Pan troglodytes) were combined to generate standard model life tables for each sex in this species. The model is compared to an estimate of survivorship of a group of wild animals, and is applied to an incomplete data set to illustrate how the model may be used to extend estimates...

The trends in 13 cause of death categories are examined with respect to expectation of life, sex differences, and period effects while misclassification of cause of death is controlled. The results suggest that as mortality declines, 1) the increasingly U-shaped age pattern of mortality is a period effect associated with the infectious diseases, 2)...

We examine the associations between nutrition and mortality at the national level. Altogether four aspects of this association are explored: (1) total calories with expectation of life, (2) dietary composition with expectation of life, (3) total calories with the age patterns of mortality, and (4) dietary composition with the age patterns of mortal...

The goodnesses of fit over the entire life span of four models of mortality are compared using life tables from Australia and the United States. The results indicate that the five-parameter Siler model fits considerably better than the more complex eight-parameter Heligman-Pollard and Mode-Busby models. On the other hand, the ten-parameter model pr...

The decline in mortality in England and Wales, between 1861 and 1964 is analysed, using competing-hazard models. These methods provide greater specificity concerning the potential biases due to misdiagnosis, and facilitate the examination of temporal shifts in the age-patterns of mortality. The results provide a number of insights into the historic...

Mortality statistics for 25 populations of the larger Old World monkeys (members of the subfamily Cercopithecinae) were evaluated with a competing hazard model of mortality. The best eight of these life tables were combined to generate a standard model life table representative of the mortality patterns of these primates. Two applications of the st...

Mortality statistics from five populations of small New World monkeys (includinsg Callithrix jaccus, Leontopithecus rosalia, Saguinus fuscicollis, and Saguinus oedipus) were combined to generate a standard model life table reflecting the mortality patterns of these primates. The model is applied to three individual populations to illustrate a strat...

Endocasts from 378 rhesus macaque skulls from the Cayo Santiago skeletal collection were measured to determine the effects of age and gender on the position and orientation of the foramen magnum. The foramen magnum migrates from a rostral to a caudal position and its angle changes during postnatal development. The angles and relative positions of t...

Efforts to breed Callitrichidae in captivity have resulted in high fertility accompanied by high infant mortality. This paper investigates the relationship between reproductive characteristics and survivorship in the Oak Ridge and Associated Universities (ORAU) callitrichid colony. Records of 2,834 individuals were analyzed using Cox Proportional H...

Biological interpretations of a competing hazards model intended to express the age pattern of mortality throughout the life span are evaluated using cause of death data. The model examined is the Siler model, which consists of three competing hazards, immature, residual, and senescent. The data employed are the worldwide sample of life tables and...

The structure of variation in human mortality patterns is explored using a five-parameter competing hazards model and standard multivariate taxonomic procedures. The data consist of 281 national life tables representing a wide range of environmental and cultural regions of the world. A general or average age pattern of mortality was generated for t...

The recent development of a number of biologically interpretable mathematical models of human mortality has facilitated the study of human variation in mortality patterns. This paper reviews the biological basis of these models, describes the models themselves, and presents the results of four anthropological applications of these models to the stu...

A five-parameter competing hazard model of the age pattern of mortality is described, and methods of fitting it to survivorship, death rate, and age structure data are developed and presented. The methods are then applied to published life table and census data to construct life tables for a Late Woodland population, a Christian period Nubian popul...

Mortality statistics for 25 populations of the larger Old World monkeys (members of the subfamily Cercopithecinae) were evaluated with a competing hazard model of mortality. The best eight of these life tables were combined to generate a standard model life table representative of the mortality patterns of these primates. Two applications of the st...

A method is described by which systematic decisions about future membership in a breeding colony of baboons are made on the basis of rarity of known genetic marker phenotypes, and reproductive performance.

A pair of two-census methods of estimating mortality levels are tested with simulated census data. The populations considered range in size from 250 to 1500 individuals of each sex; censuses were taken at intervals of five and ten years. In general, the methods are resistant to bias, and yield variances similar in magnitude to those obtained using...

Siler's five-parameter competing-risk mortality model has been applied to a world-wide sample of life tables, and to the Coale and Demeny model tables. This model incorporates three additive hazards that correspond to the three types of mortality described by Pearl and Miner in 1935. The results suggest that this model fits life tables more accurat...

A detailed demographic analysis was made of the Wisconsin Regional Primate Research Center rhesus colony from vital statistics recorded over a 20-year period. Techniques used were based on demographic and epidemiological methods developed for human populations, which provide the potential for making standardized measurements within captive primate...

A mathematical method of maximizing the reproductive efficiency of captive populations is evaluated for its efficacy in very small breeding groups and for its effect on the loss of genetic variability. The evaluation consists of comparing reproductive performance of simulated populations having demographic characteristics similar to a small troop o...

A recent extension of stable-population theory to nonstable populations by Preston and Coale (1982) provides a number of new indirect techniques that are much more accurate and powerful than those previously available. This is an important development for anthropological research, since the new methods are well suited to estimating the vital rates...

A method of estimating the parameters of population growth, based upon nonstable population theory, is presented. Data required for this method consist of age structures taken from two censuses, and the distribution of parental ages at birth. These data are typically more reliable and easier to collect than those required for transitional methods r...

A discrete, environmentally coupled, size-specific model of microbial population dynamics in continuous culture is presented. It is mathematically simpler than other models based on similar assumptions and lends itself to numerical and analytic solutions. It displays several phenomena which have been reported in the experimental literature but whic...

A method of fitting a model life table is presented that requires data from two censuses taken some years apart. The method does not depend on vital registration or the assumption of a stable age structure. Abridged life tables and an estimate of the birth rate (a biproduct of the fitting procedure) are calculated for the Trio of Surinam. An evalua...

A hypothetical model concerning the structure of aboriginal California trophic systems is presented. The dynamics of each possible state of the system is generated theoretically and then tested using previously published data. It is determined that a state of competitive coexistence of a fish-regulated predatorprey competition relationship between...

Thesis (Ph. D.)--Pennsylvania State University, 1982. Includes bibliographical references (leaves [237]-246). Photocopy. s