Temporal Trends in Phthalate Exposures in the Swedish pregnancy cohort

Abstract

INTRODUCTION: Epidemiological studies have found that the general population is exposed to chemicals that may interact with the endocrine system in humans and animals, so called endocrine disrupting chemicals (EDCs). In the SELMA study we investigate the importance of pre- and post-natal exposure of EDCs and life style factors for development of chronic diseases and development in offspring in Sweden. Phthalates are a group of EDCs used in plastics and numerous consumer products. Temporal trends in urinary levels of phthalate metabolites in pregnant women were examined. METHODS: Metabolites of five phthalate (DEP, DBP, BBzP, DEHP and DiNP) were analyzed by liquid chromatography tandem mass spectrometry in urine from 2,356 pregnant women in the SELMA study. The samples were collected at their first visit (week 10) to the public antenatal care centers in Sweden during the period of September 2007 to April 2010. The samples were analyzed in a randomized order. Least square geometric means (LSGM) of phthalate metabolites were compared between different SELMA sampling years with covariates included. RESULTS: Ten phthalate metabolites were 100% detectable in all SELMA subjects. All DEHP metabolites showed a decreasing trend (p<0.01) over the sampling period (2007-2010), 2010 LSGM concentrations decreased 7% when compared with 2007. Also, the DEP metabolite decreased (10%). For DiNP phthalates, a steady upward temporal trend was found where LSGM concentration of ∑DiNP metabolites increased significantly between 2007 and 2010. LSGM concentrations increased 4.1% (p=0.15) in 2008, 7.5% (p=0.011) in 2009, and 19% (p=0.0002) when compared with 2007. Conclusions: Our analysis from a large sample suggests that Swedish exposure to some phthalates – measured as their metabolites in urine of pregnant women – has changed during a 2.5 year period from 2007 to 2010. We found that DEHP and to a lower degree DEP metabolite levels have decreased while DiNP metabolite levels have increased.