PhD ceremony Ms. T. Wu: Influence of genes, environment and their interaction on risk factors for asthma and cardiovascular disease

PhD ceremony: Ms. T. Wu, 9.00 uur, Academiegebouw, Broerstraat 5, Groningen

Dissertation: Influence of genes, environment and their interaction on risk factors for asthma and cardiovascular disease

Promotor(s): prof. H. Snieder

Faculty: Medical Sciences

In this thesis we applied different gene-environment interaction methods to study risk factors for asthma and cardiovascular disease. It starts with a prospective candidate gene study, which gives more insight in interaction between maternal passive smoking and maternal metabolic enzyme genes on infant birth weight. The greater part of this thesis consists of several twin studies, which improve and extend the application of twin modeling to explore gene-environment interactions. Univariate structural equation modeling was performed in chapter 3 to examine heritabilities of responses to environmental challenges, such as bronchial hyper responsiveness. Similarly, in chapter 4, heritabilities of overnight urinary excretion rates of norepinephrine and epinephrine, which reflect basal sympathetic activity levels as a measure of chronic exposure to stress, were explored by the same twin modeling. A Meta-analysis that pooled the results of all published twin studies on heritablities of heart rate or blood pressure (BP) reactivity to the cold pressor test or various mental stress tasks was presented in chapter 5. In chapter 6, we used bivariate modeling to estimate the contribution of genes and environment to the individual differences in levels of BP and underlying hemodynamic characteristics at rest and during stress. Finally, in chapter 7, Purcell’s GxE model was applied to examine the extent to which body mass index as a measure of adiposity and treated as an environment factor in this model, may modify the genetic influence on BP. These results have implications and provide guidance to further gene finding efforts for underlying risk factors of asthma and cardiovascular disease.