April 4, 2016 Kim Krisberg 0Comment

In debates over air pollution control, it’s always a tug-of-war between the cost to business and the cost to public health. Late last month, a study emerged with new data for the public health column: the cost of the nation’s nearly 16,000 annual preterm births linked to air pollution is more than a whopping $5 billion.

Published in Environmental Health Perspectives, the study estimated the burden of U.S. preterm births and related costs associated with fine particulate matter (PM2.5) — a pollutant from motor vehicles and the burning of fuels such as wood and coal. While preterm birth is a complex, multifactorial event, research is increasingly pointing to environmental exposures such as air pollution as an independent contributor. Preterm birth (birth at less than 37 weeks of gestation) affects about one in every eight U.S. babies, is the leading cause of infant death and a top cause of long-term neurological disabilities. However, study co-author Leonardo Trasande, an associate professor in the Departments of Pediatrics, Environmental Medicine and Population Health at New York University, noted that preterm birth is often a preventable event, and fine particulate pollution is a modifiable contributor — “you just have to find the source and regulate it.”

“What’s more salient here too and what should raise an alarm is that just this one environmental contributor produces such a substantial proportion of preterm births in the U.S. — and this isn’t the only environmental exposure that likely contributes to preterm birth,” Trasande told me. “So for the average obstetrician or public health worker, this adds to the need for a bit of a paradigm shift — (preterm birth) isn’t simply avoidable through medical means; we also need to start considering environmental causes and preventing them.”

To conduct the study, Trasande and his colleagues analyzed federal health and environmental data from agencies such as the Centers for Disease Control and Prevention and Environmental Protection Agency and then measured air pollution exposures and preterm births at the county level. They then estimated the costs related to air pollution-attributable preterm births, such as early death, decreased IQ, decreased work productivity and overall poor health. While the science on exactly how air pollution triggers preterm birth is still emerging, some research points to oxidant stress, inflammation and placental weakening as possible mechanisms. Co-authors Trasande, Patrick Malecha and Teresa Attina write:

A major barrier to reductions in outdoor air pollution is the perception that these reductions will undermine economic productivity. As with outdoor air pollution-associated respiratory illnesses, the costs associated with adverse birth outcomes are born by society, rather than those who gain from industrial processes that emit pollutants. These include health care costs for treatment of prematurity-associated comorbidities and lost economic productivity due to (preterm birth)-associated reductions in cognitive potential. Yet, to our knowledge, estimates of the air pollution-attributable burden of preterm birth, and associated economic costs have not been made. Our primary objective was to provide an estimate of the economic costs associated with (preterm births) attributable to PM2.5 exposure (as a proxy for outdoor air pollution) in the US, estimates that could be used by decision-makers when regulatory interventions to reduce air pollution exposures are considered.

In examining data on more than 475,000 preterm births across 48 states, researchers found that more than 3 percent of preterm births in 2010 were linked to fine particulate matter exposure. Those preterm births costs $760 million in medical care and $4.33 billion in lost economic productivity. In total, the study estimated $5.09 billion in preterm birth-related costs that may be due to air pollution.

Not surprisingly, the burden varied across the country. For example, California had the largest number of preterm births linked to fine particulate matter — more than 2,100 at a cost of $692 million. The highest fraction of preterm births associated with PM2.5 was found in Ohio, while the lowest fractions were in New Mexico and Wyoming. In general, rates of air pollution-related preterm births were higher in major urban regions.

“These costs add to the aggregate costs of environmental health issues in children,” Trasande said.

Next, Trasande said he plans to expand this line of research to a global scale. He noted that while women can take some action to reduce their exposures to hazardous air pollutants, real inroads will be made at the policy level.

“There are personal-level behaviors one could take, but the ultimate answer will come in the form of policymaking,” he told me. “And these data add to the business case for prevention.”

To download a full copy of the preterm birth study, visit Environmental Health Perspectives.

Kim Krisberg is a freelance public health writer living in Austin, Texas, and has been writing about public health for nearly 15 years.

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