Phthalates are commonly used to soften plastic materials to make them usable in various products and industries, including food service and medical. It has been estimated from previous research that 98 percent of all phthalate use is for plastics-related purposes.

A study from NYU Langone’s Division of Environmental Pediatrics, published in the journal Lancet eCinicalMedicine, looked at a phthalate called di-2-ethylhexylphthalate (DEHP), which is used to make plastic products more flexible, and diisononyl phthalate (DiNP), a common replacement for DEHP. Previous studies have linked exposure to these chemicals to higher preterm birth rates. NYU Langone researchers estimate that DEHP exposure contributed to about 1.97 million preterm births in 2018 alone, or more than 8 percent of the world’s total.

A New Disease Burden Model

Although previous literature has linked exposure to these chemicals to higher preterm birth rates, no analysis had yet attempted to estimate the global burden associated with this relationship. This new model provides the first global estimates of morbidity and mortality associated with exposure to these chemicals.

For this analysis, researchers compiled global DEHP and DiNP exposure in 2018 across more than 200 countries and territories using biomonitoring data from large national surveys conducted in the United States, Europe, and Canada. For regions without publicly available data, they supplemented estimates using results from a prior meta-analysis. The team then abstracted effect estimates of the relationship between phthalates and preterm birth from a recent epidemiological study, and also calculated ranges of possible effect estimates using global meta-analyses. Finally, they combined this information with global data on preterm births and neonatal deaths to estimate the proportion of these outcomes attributable to DEHP exposure.

The Estimated Burden Is Considerable, and Unequal

DEHP exposure was estimated to be linked to 1.97 million preterm births in 2018, or more than 8 percent of the world’s total. The chemical was also estimated to be linked to 74,000 neonatal deaths. Burdens associated with DiNP were comparable. The estimated costs of plastic-associated preterm birth mortality range from millions to hundreds of billions of dollars for both DEHP and DiNP. Uncertainty ranges indicated that DEHP estimates could be up to four times lower than the main estimates or slightly higher, while DiNP estimates could be as much as 10 times lower. Even under the most cautious assumptions, the results point to a substantial economic and health burden.

Phthalates are in widespread use globally, but this analysis reveals unequal estimated burdens. Some regions were estimated to have higher burden than others, with the highest absolute burden being estimated in the Middle East and South Asia, representing 54 percent of estimated morbidity. In addition, Africa was estimated to have a disproportionate share of deaths compared with its share of overall premature cases.

One possible explanation for the increased morbidity in these regions is that they face higher rates of exposure to chemicals, perhaps because they are undergoing a boom in plastic production, or because much of global plastic waste is taken in by countries in these regions. In addition, some regions such as Africa may face a “double burden” scenario, with comparatively high underlying rates of preterm birth-related mortality and also high exposure levels to plastics chemicals. Detailed results for each region of the world can be found in the table at the end of this section.

Aggregate results for regions can be seen in the table Global Preterm Birth Morbidity and Mortality Burden Linked to Phthalate Exposure. This table presents estimates of burden associated with DEHP and DiNP exposures across different global regions. The values include the estimated number of preterm births, deaths, years of life lost (YLL), years of life lived with disability (YLD), and the percentage of regional preterm birth that was estimated to be associated with exposure (PAF). Each row represents a specific region, with a global total provided at the bottom. ND stands for “no data available.” Download the full table of data. 

Global Preterm Birth Morbidity and Mortality Burden Linked to Phthalate Exposure

	Preterm births		Years of life lost		Year of life lived with disability		Deaths		Percent of regional PTB associated with chemical exposure
World Region	DEHP contribution	DiNP contribution	DEHP contribution	DiNP contribution	DEHP contribution	DiNP contribution	DEHP contribution	DiNP contribution	DEHP	DiNP
Africa	511,790	168,144	2,285,991	751,041	121,569	39,940	25,442	8,359	7.298	2.398
East Asia and the Pacific	226,157	176,982	600,422	469,861	144,518	113,092	6,676	5,223	7.93	6.206
Australia	2,187	ND	1,711	ND	2,145	ND	18	ND	7.215	ND
Middle East and South Asia	1,067,758	1,229,819	3,467,111	3,993,345	845,207	973,492	38,543	44,392	10.67	12.289
Canada	1,484	367	1,520	376	1,426	353	18	4	3.347	0.828
Europe	35,581	78,953	36,214	80,355	29,541	65,552	403	892	4.633	10.28
Latin America	111,006	156,932	272,579	385,352	68,588	96,964	3,031	4,285	8.239	11.647
United States of America	16,729	66,553	21,565	85,792	14,763	58,738	240	954	3.319	13.204
Global	1,972,692	1,877,750	6,687,113	5,766,122	1,227,757	1,348,131	74,371	64,109	8.742	8.321

Visualizing Burden

To visualize the burden of phthalates estimated by this model, researchers at NYU Langone have created an interactive map showing results from the study.

The map below represents an estimate of the number of estimated preterm births, neonatal deaths, YLLs, and YLDs linked to DEHP and DiNP in 2018. Users can choose to these metrics, regional percent of preterm birth associated with these chemicals, or percent of the global total preterm birth in each country. Users can hover over each country on the map to see the country name and a snapshot of country-level information.

The darker the color on the map, the higher the estimated burden.

Download all the data shown on the map.

Call to Action

This analysis highlights the need for additional research, including expanded biomonitoring, with much of the world lacking comprehensive biomonitoring surveys for plastics-related chemicals. The model highlighted greater uncertainty and data gaps for DiNP, emphasizing the importance of further investigation into DEHP replacement chemicals. Future work should also incorporate a broader range of compounds, as these models did not capture the full mixture of plastic-related chemicals to which people are exposed. Support for this research and additional study is needed to truly understand the global burden of chemical exposures.

In 2022, the United Nations Environment Assembly announced a legally binding agreement to end plastic pollution. This analysis provides crucial evidence to support such global initiatives. Implementing regulatory measures to limit exposure to phthalates as a class could help reduce the global PTB burden, particularly in areas with high PTB risk and high underlying exposure rates to these chemicals.