Prenatal risk factors for childhood cancer and health: maternal diabetes, occupational physical activity and nativity

Protecting and improving the health outcomes of children is of fundamental importance. The first two studies of this dissertation focus on prenatal risk factors for childhood cancers. The first study includes cancer cases identified from the Danish Cancer Registry and diagnosed under 19 between 1977 and 2016. Controls were selected from Central Population Registry and matched to cases on sex and birth year. We also included cases ascertained from the Taiwanese Cancer Registry and all children born in Taiwan between 2004 and 2014 that are listed in the Maternal and Child Health database. With access to population-based registries in Denmark and Taiwan, we examined the association between maternal diabetes and childhood cancer risk. In Denmark, the risks of central nervous system tumors among children prenatally exposed to maternal type I diabetes were increased, particularly for glioma. In Taiwan, the risks of glioma were elevated among children whose mothers had gestational diabetes. There was a two-fold increased risk for hepatoblastoma.Our second study includes cancer cases identified from the Danish Cancer Registry and diagnosed under 19 between 1968 and 2016 to investigate the effect of maternal occupational physical activity and childhood cancer risk. Overall, high levels of maternal occupational physical activity during pregnancy were associated with a higher risk of medulloblastoma with an indication of a dose-response pattern. Among health care professionals, maternal occupational physical activity exposures increased the risk of melanoma in offspring. The distribution of adverse pregnancy, birth and subsequent child developmental outcomes in the U.S. is characterized by pronounced racial-ethnic disparities and maternal immigrant status. In the third study, we compared metabolic profiles generated by the liquid chromatography-high resolution mass spectrometry platform of newborns of foreign-born and US-born Hispanic women in California (1983-2011) in an untargeted manner. Dried blood spots of eligible healthy children were collected by the California Genetic Disease Screening Program. We found that differences in metabolic profiles exist between newborns of US-born and foreign-born Hispanic mothers with an indication of alterations in inflammatory and oxidative stress pathways which could not be explained by the measured demographic, health behaviors, gestational and environmental factors