title: Maternal benzene exposure and low birth weight risk in the United States: a natural experiment in gasoline reformulation.
abstract: We investigate the relationship between maternal exposure to benzene and birth weight outcomes for resident births in the United States in 1996 and 1999, taking advantage of a natural experiment afforded by the regulation of benzene content of gasoline in various American cities. Regression results show that a unit increase (μg/m(3)) in maternal exposure to benzene reduces birth weight by 16.5 g (95% CI, 17.6 to 15.4). A unit increase in benzene exposure increases the odds of a low birth weight event by 7%. Similarly, a 1 μg/m(3) increase in benzene concentration increases the odds of very low birth weight event by a multiplicative factor of 1.23 (95% CI, 1.19 to 1.28). Difference-in-differences analyses show that birth weight increased by 13.7 g (95% CI, 10.7 to 16.8) and the risk of low birth weight decreased by a factor of .95 (95% CI, .93 to .98) in counties experiencing a 25% decline in benzene concentrations from 1996 to 1999. Public health policy and economic implications of results are discussed.
authors.affiliation: Department of Economics, Center for Disaster and Risk Analysis, Colorado State University, C312A Clark Building, Fort Collins, CO, 80523-1771, USA. szahran@colostate.edu
authors.forename: Sammy
authors.initials: S
authors.lastname: Zahran
authors.forename: Stephan
authors.initials: S
authors.lastname: Weiler
authors.forename: Howard W
authors.initials: HW
authors.lastname: Mielke
authors.forename: Anita Alves
authors.initials: AA
authors.lastname: Pena
mesh_terms: D000293:Adolescent; D000328:Adult; D000393:Air Pollutants / Q000032:analysis / Q000633:toxicity*; D001554:Benzene / Q000032:analysis / Q000633:toxicity*; D001724:Birth Weight / Q000187:drug effects*; D005260:Female; D005742:Gasoline / Q000032:analysis / Q000633:toxicity*; D005865:Gestational Age; D006801:Humans; D007230:Infant, Low Birth Weight; D007231:Infant, Newborn; D018811:Maternal Exposure / Q000009:adverse effects*; D008875:Middle Aged; D011247:Pregnancy; D012044:Regression Analysis; D012306:Risk; D014481:United States; D055815:Young Adult
chemical_list: D000393:Air Pollutants; D005742:Gasoline; D001554:Benzene