PROTECT Study Finds Decrease in Phthalate Exposure Coincides with Increase in Phthalate Replacement Chemicals in PROTECT Cohort

Phthalates are chemicals commonly used in industrial and consumer products that act as plasticizing agents, which serve to make materials softer or more flexible. These chemicals are typically found in consumer items such as food packaging and personal care products. Some of the common phthalates found in consumer products are di(2-ethylhexyl) phthalate (DEHP), di-isononyl phthalate (DINP), and dioctyl phthalate, diethyl phthalate (DEP) and dibutyl phthalate (DBP). Among these different products, there are two main types of phthalates that appear depending on the product. High molecular weight phthalates, which have 5 or more carbons length ester side-chain, are often found in food packaging, medical devices, and vinyl products. Low molecular weight phthalates, which have 1-4 carbons length ester side-chain, are commonly found in personal care products.

Exposure to phthalates has been associated with adverse effects during pregnancy as well as childhood developmental and cardiometabolic outcomes. Due to these findings and public scrutiny, phthalates have been removed from many products in the United States. However, they have been slowly replaced by other chemicals as shown by the decreasing concentrations of phthalates and the increase of their replacements in urine in this PROTECT study.

This study aimed at characterizing the sociodemographic characteristics and sources associated with phthalates exposure, as well as the temporal trends in their exposure over the course of 7 years. It was conducted on PROTECT’s cohort of pregnant women from Puerto Rico. In the study, prenatal spot urine samples collected at study visits at ~18, 22, and 26 weeks of gestation were used to measure phthalates. Two phthalate replacements, Di-2-ethylhexyl terephthalate (DEHTP) and Di(isononyl)cyclohexane-1,2-dicarboxylate (DINCH), were also analyzed. Phthalates have short biological half-lives in the human body (hours) because they are quickly metabolized and excreted, so repeated measurements of urine samples allow researchers to more accurately characterize exposure during pregnancy. Information on demographic and socioeconomic factors, as well as self-reported product use and food consumption, were also collected using questionnaires at each study visit. The team evaluated these data as predictors of urinary phthalate concentrations to help inform potential sources of exposure. For this analysis, they used linear mixed effects models which enabled them to examine the relationships of repeated phthalate measurements and repeated predictors.

“The results confirmed there has been a reduction of phthalates exposure and an increase of their replacements; additionally, we found that drinking public water, the use of certain personal care products and ice cream consumption are important sources of phthalates in this population, whereas cleaning products were associated with lower phthalate exposures,” explains one of the authors and Project 1 researcher Pahriya Ashrap.

Due to these results, Pahriya and the research team advise “reducing when possible the use of perfume, cosmetics, and hair products, especially during pregnancy. On the other hand, the use of detergents, cleaners, or liquid soap is encouraged as they can help lower the exposure to phthalates.” Furthermore, given the high incidence of preterm birth in Puerto Rico, it is important to educate on and characterize the toxicants to which pregnant women are exposed.