Filling gaps in population estimates of phthalate exposure globally: A systematic review and meta-analysis of international biomonitoring data

Abstract

Many phthalates have been identified as endocrine-disrupting chemicals because they alter hormone functions throughout the lifespan. Nationally representative biomonitoring data are available from the United States, Canada, and Europe, but data elsewhere are sparse, making extrapolations of related disease and disability burdens difficult. We therefore examined trends in urinary phthalate metabolite concentrations in non-occupationally exposed populations in countries other than the United States, Canada, and Europe, where representative data are already available at the country level.

We systematically reviewed studies published between 2000 and 2023 and analyzed changes in urinary phthalate metabolite concentrations across time using mixed-effects meta-regression models with and without a quadratic term for time. We controlled for region, age, and pregnancy status, and identified heterogeneity using Cochran's Q-statistic and I² index.

Our final analysis consisted of 216 studies. Non-pregnant and youth populations exhibited nearly 2.0-fold or greater difference in concentration compared to pregnant and adult populations. Phthalates with significant regional differences had 10-fold higher concentrations in the Middle East and South Asia than in other regions. Our meta-regressions identified an exponential increase in DBP exposure through MnBP concentration internationally (beta: 0.65 ng/mL/year²) and in Eastern and Pacific Asia (EPA) (beta: 0.78 ng/mL/year²). Most DEHP and DnOP metabolites significantly declined internationally and in EPA, while MEP concentration declined by 10.62 ng/mL in Latin America and 8.98 ng/mL in Africa over time.

Our findings fill gaps in phthalate exposure data and set the stage for further analysis of the attributable disease burden and cost at regional and international levels, especially in low- and middle-income countries.