Phthalates: A Full Chain Story : Connecting phthalate sources, indoor dust, human intake, and airway symptoms in children

Abstract: Phthalates are widely used in a large number of consumer goods and building materials from which they can leach and contaminate the environment such as indoor dust and air. It is unclear how phthalate sources in our homes and indoor dust contribute to human intake and airway symptoms in children. This thesis aims to contribute to the understanding of phthalate exposure by exploring connections between phthalate sources in home environments, indoor exposure, human intake, and childrens’ airway symptoms. It utilizes data in the Swedish SELMA study, including measurements of indoor dust phthalate levels and corresponding metabolites in prenatal maternal urine, and information on health outcomes and cofactors from self-administered questionnaires. The results show higher levels of three phthalates (DnBP, BBzP and DEHP) in dust from homes with PVC flooring. Four phthalates in dust (DEP, DnBP, DiBP, and BBzP) were positively correlated with corresponding maternal urinary metabolites. The dust was estimated to explain a 1-28% (median) contribution to the total daily intake of the analysed phthalates among pregnant women. Living in homes with PVC flooring was linked to a higher intake of BBzP and DEHP. Further, associations were found between prenatal phthalate exposure (BBzP, DiNP, DiDP and DPHP) and wheeze, and phthalates in dust (DEP, BBzP and DEHP) and croup in children before 2-years-of-age.This thesis connects a full chain of factors relevant for human phthalate exposure. Sources in our homes were linked to higher levels in dust and to human intake. Also, both regulated and non-regulated phthalates were associated with human intake and airway symptoms. Combined with other research results, this implies that using new phthalates as replacements might not be optimal, and we could consider regulating phthalates as a group. Any links to effects in older children is unknown, still, limiting indoor phthalate sources could reduce intake and benefit overall public health.