Dr. Gage’s research over the past three years encompasses several areas. One is the development of Covariate Density Defined (CDD) mixtures of regressions and their application to the analysis of birth outcomes and infant mortality. This is a method of controlling for “unobservable” heterogeneity in the context of regression, using parametric mixture models. This project has produced a number of papers, including two during the last three years. The first paper, which addressed the “pediatric paradox,” that is, the finding that low-birth-weight African-American infants have lower mortality than their European-American peers, appeared in Human Biology. A second paper, an extension of CDD mixtures of logistic regression to a multivariate parametric mixture model based on birth weight and gestational age is in press in The American Journal of Human Biology. Gage’s CDD project has received the Gabriel W. Lasker Award for research in Human Biology as well as a 2004 PAA poster award.
In a different area of research, a paper in The American Journal of Physical Anthropology examined changes in mortality occurring at the transition to agriculture in the prehistoric Middle East. This is one of only a few studies that can demonstrate a definitive change with agriculture, in this case, a decline in mortality. Additionally, a paper in the Yearbook of Physical Anthropology reviews the demographic and epidemiological transitions from prehistoric times to the present. The main thesis of this paper is that after correcting for misclassification of cause of death, heart disease appears to decline with the demographic transition. This phenomenon was first observed by Preston and reaffirmed in several papers by Gage. The observation that heart diseases has been on the decline is consistent with the growing biological understanding that heart disease has an infectious component.
Externally funded research: Gage has held two R01s in the last three years for the development and application of CDD mixtures of logistic regressions to issues of infant mortality (both under the title, “The Determinants of Infant Mortality: Statistical Models.” Dr. Gage is also a Co-Investigator on the Albany Population Center Grant.
Gage has held two R01s in the last three years for the development and application of CDD mixtures of logistic regressions to issues of infant mortality. Dr. Gage is also a Co-Investigator on the Albany Population Center Grant.
Work
in progress and pending/planned research projects.
Gage’s development of CDD mixtures of regressions (CDDmlr) is ongoing. An extension of CDD mixtures of logistic regression to a multivariate parametric mixture model based on birth weight and gestational age for comparing African/European-American disparities in infant mortality has been submitted to Demography. The continuation of this project is beginning to look at covariates, such as altitude, SES, smoking, twins etc., that are also associated with “pediatric paradoxes.” He is currently preparing a paper describing a second CDDmlr birth-weight-by-gestational-age model and a second paper describing the impact of maternal age and parity on infant mortality.
In addition, Gage is currently compiling a review of recent research on the evolution of virulence and its implications for the prehistoric and historic decline in mortality with the development of industrialization. Simple models of the evolution of virulence suggest that virulence increases with the growth of populations. However, exactly the opposite has been observed historically among humans. More complex models have questioned this result for spatially distributed populations and social organisms. With his collaborators, who include two University at Albany biologists, Thomas Caraco (a theoretical ecologist) and Ing Nag Wang (who studies the evolution of microorganisms), he is examining which model best describes the human experience theoretically and empirically. In a second initiative, Gage is collaborating with Dr. Thomas Brutseart to examine insulin resistance in a population of Native Americans living in Costa Rica. Diabetes phenotypes have not been studied in Native American populations outside of North America. Preliminary fieldwork with University at Albany funding is underway. Gage and Brutseart have additionally applied for funding to examine the “fetal programming” hypotheses with respect to several measures of physical fitness within the US. Continuing his interest in the demography of endangered species, Gage is currently conducting of comparison of chimpanzee life tables for wild and captive animals.
Dr. Gage’s contribution has come chiefly in the areas of computing and statistics. Dr. Gage was Director of the Computing and Statistics core on the original P30 grant to CSDA. In addition, he was PI on the NSF grant that funded CSDA’s computing infrastructure, which he designed and implemented. Dr. Gage is currently Director of the Computing/Statistics Core of the R24. He has designed and is currently in the process of implementing extensive upgrades to the computing infrastructure. He also serves as a statistical consultant for many CSDA associates.
Dr. Gage and his research team have made extensive use of the computing infrastructure as well as of information and grant administrative services.