Practical Tools For Robust Analysis Of Large Epidemiological Studies With Incomplete Data
Funder
National Health and Medical Research Council
Funding Amount
$358,492.00
Summary
Studies of the causes and consequences of health outcomes follow large cohorts of individuals for long time periods. A major challenge in analysing data from these studies is that information is often incomplete. Participants rarely complete all waves of data collection, or provide all requested information. Statistical research has led to increased use of a statistical method (multiple imputation) that recovers information from incomplete cases. This project will develop and improve this method
Statistical Methods For Handling Missing Data In Longitudinal Studies
Funder
National Health and Medical Research Council
Funding Amount
$198,000.00
Summary
Modern epidemiological research has a strong focus on studying the causes and consequences of major health outcomes over the life span. Studies are increasingly conducted on large cohorts of individuals over long periods of time, extending from before birth through to the later years of life. An example of this type of study is the Victorian Adolescent Health Cohort Study, which began in 1992 with participants aged 15 and is now seeking funding for a 9th wave of data collection in 2005. A major ....Modern epidemiological research has a strong focus on studying the causes and consequences of major health outcomes over the life span. Studies are increasingly conducted on large cohorts of individuals over long periods of time, extending from before birth through to the later years of life. An example of this type of study is the Victorian Adolescent Health Cohort Study, which began in 1992 with participants aged 15 and is now seeking funding for a 9th wave of data collection in 2005. A major challenge that arises in analysing data from studies of this kind is the difficulty created by the occurrence of missing data. In longitudinal studies with multiple measurement occasions, participants rarely complete all waves of data collection, and even when present an individual may not provide data on all study variables. Common practice in analysing such data is to omit individuals entirely if they have a missing value on any of the variables required for the analysis in question. This approach can lead to major biases in conclusions, by excluding individuals in whom patterns of association may be quite different than among those retained, and at best leads to loss of reliability in findings due to the reduction in numbers available for analysis. Recent statistical research has led to a range of new techniques for better handling of missing data in such studies, including the method of multiple imputation (MI), under which multiple copies of the dataset are created with imputed values filled in for the missing values. This approach has enormous potential for helping to produce better answers from large longitudinal studies but a number of issues require research to ensure that the method is made available to researchers in a convenient form and, most importantly, used in a way that leads to sound conclusions. This project will address many of these issues, leading to enhanced capacity to extract valuable information from large epidemiological studies.Read moreRead less
The Role Of Interferon Gamma And Nitric Oxide As Downregulating Molecules In Central Nervous System Inflammation
Funder
National Health and Medical Research Council
Funding Amount
$526,644.00
Summary
Cytokines are soluble factors which participate in inflammatory responses. Interferon gamma is a cytokine which in the context of central nervous system inflammation has been considered a Obad? molecule, as has the gas nitric oxide which is induced by interferon gamma. We now have direct evidence that indicate quite the contrary, ie interferon gamma and nitric oxide can a do act as down regulators of inflammation. The present work is designed to determine if this down regulating function is rest ....Cytokines are soluble factors which participate in inflammatory responses. Interferon gamma is a cytokine which in the context of central nervous system inflammation has been considered a Obad? molecule, as has the gas nitric oxide which is induced by interferon gamma. We now have direct evidence that indicate quite the contrary, ie interferon gamma and nitric oxide can a do act as down regulators of inflammation. The present work is designed to determine if this down regulating function is restricted only to a single model of CNS inflammation or is a general phenomenon within the CNS. The project will also involve a number of experiments designed to elucidate the mechanism(s) by which down regulation occurs. This project is highly significant in that a single uncontrolled clinical trial of interferon gamma for the therapy of MS has been carried out and reported as indicating that interferon gamma made the disease worse. The design of that trial however was such that the validity of that claim is questionable. If our experiments confirm the general nature of interferon gamma as a down regulator in inflammation in a number of different models of MS then a case for revisiting the use of interferon, or a downstream product of interferon, in the therapy of MS might be made.Read moreRead less