Graduation Year
2013
Document Type
Thesis
Degree
M.S.P.H.
Degree Granting Department
Epidemiology and Biostatistics
Major Professor
Aurora Sanchez-Anguiano
Co-Major Professor
Kendra Vehik
Keywords
autoimmune disease, children, environmental exposures, hygiene hypothesis, pets
Abstract
Research on exposure to animals and risk of type 1 diabetes (T1D) has had conflicting results with some researchers finding that animal exposure reduces the risk of T1D and others finding no association between animal exposure and T1D. Previously conducted studies on the association between animal exposure and T1D are case-control studies that have been limited by recall bias. The purpose of this study is to investigate the association between early life animal exposure and the risk of persistent, confirmed islet autoantibodies (IA) and T1D diagnosis among an eligible cohort of genetically high T1D risk participants enrolled in the international prospective cohort study, The Environmental Determinants of Diabetes in the Young (TEDDY). It is hypothesized that children who are exposed to animals in early life will have a lower risk of developing IA and T1D than children who are not exposed to animals in early life.
A total of 7,432 TEDDY participants were included in the study. The associations between early life animal exposure and the outcomes of interest were explored using Cox proportional hazards models. In order to control for confounding, a propensity score analysis was applied by three different methods: adjustment for the propensity score variable in the Cox proportional hazards model, stratification on propensity score groups, and propensity score pair matching.
Early life animal exposure was not associated with diabetes autoimmunity or T1D onset in this genetically high T1D risk population. These findings were consistent across all three propensity score analysis methods and when directly adjusting for HLA type. The hypothesis that children who are exposed to animals in early life will have a lower risk of developing IA and T1D than children who are not exposed to animals in early life is not supported by this study.
The results of this study suggest that there is no association between early life animal exposure and development of T1D. Performing this analysis again after longer follow-up has been completed for the study population is recommended as it may elucidate the effect of animal exposure on T1D and IA risk. Further studies are also needed on animal exposure and T1D in different types of environments (e.g., high residential density) and the effect of different types of animal exposures (e.g., species, duration) on T1D and IA risk. Additionally, studies on differences in perceptions of pets across countries could also aid the interpretation of studies on animal exposure and health outcomes.
Scholar Commons Citation
Hall, Callyn, "An Analysis of the Association between Animal Exposures and the Development of Type 1 Diabetes in the TEDDY Cohort" (2013). USF Tampa Graduate Theses and Dissertations.
https://digitalcommons.usf.edu/etd/4501
