Associations between Vaccines and Mid Upper Arm Circumference - A Longitudinal Approach

Specialeforsvar ved Christian Bjerregård Øland

Titel: Associations between Vaccines and Mid Upper Arm Circumference - A Longitudinal Approach

Abstract: Studies into the effects of vaccines are facing increasing difficulty by falling mortality rates increasing the sample sizes needed to conduct studies. This thesis aims to find a suitable methodology to investigate effects of vaccines using longitudinal measurements of the mid-upper-arm-circumference (MUAC). The MUAC is used as a proxy for health and nutritional status of, and it provides an useful indicator of a populations health status. Using linear mixed models with special focus on confounding, time-varying effects and missing data. This thesis investigates and describes suitable methodology for a proper analysis of health demographic surveillance data. Missing data has a special focus, with a simulation study to evaluate suitable imputation strategies. Showcasing the methodology, an analysis is carried out on a randomised control trial in a Sub-Saharan west African country. The trial investigates the effect of measles carrying vaccine at 4.5 months and 9 months of age vs. 9 months of age. The analysis were able to provide a full follow-up picture from 4.5 months to 3 years of follow-up, where the distinguishing effects seemingly happened for girls vaccinated in the rainy season. Thus, the methodology provides valuable tools and insights to analyse possible associations between vaccines and the MUAC.

Vejledere: Helle Sørensen, Aksel Karl Georg Jensen
Censor:  Bo Martin Bibby, Aarhus Universitet