title: Residential proximity to methyl bromide use and birth outcomes in an agricultural population in California.
abstract: BACKGROUND
  Methyl bromide, a fungicide often used in strawberry cultivation, is of concern for residents who live near agricultural applications because of its toxicity and potential for drift. Little is known about the effects of methyl bromide exposure during pregnancy.
  
  
  OBJECTIVE
  We investigated the relationship between residential proximity to methyl bromide use and birth outcomes.
  
  
  METHODS
  Participants were from the CHAMACOS (Center for the Health Assessment of Mothers and Children of Salinas) study (n = 442), a longitudinal cohort study examining the health effects of environmental exposures on pregnant women and their children in an agricultural community in northern California. Using data from the California Pesticide Use Reporting system, we employed a geographic information system to estimate the amount of methyl bromide applied within 5 km of a woman's residence during pregnancy. Multiple linear regression models were used to estimate associations between trimester-specific proximity to use and birth weight, length, head circumference, and gestational age.
  
  
  RESULTS
  High methyl bromide use (vs. no use) within 5 km of the home during the second trimester was negatively associated with birth weight (β = -113.1 g; CI: -218.1, -8.1), birth length (β = -0.85 cm; CI: -1.44, -0.27), and head circumference (β = -0.33 cm; CI: -0.67, 0.01). These outcomes were also associated with moderate methyl bromide use during the second trimester. Negative associations with fetal growth parameters were stronger when larger (5 km and 8 km) versus smaller (1 km and 3 km) buffer zones were used to estimate exposure.
  
  
  CONCLUSIONS
  Residential proximity to methyl bromide use during the second trimester was associated with markers of restricted fetal growth in our study.
authors.affiliation: Department of Demography, University of California, Berkeley, Berkeley, California 94704 , USA.
authors.forename: Alison
authors.initials: A
authors.lastname: Gemmill
authors.forename: Robert B
authors.initials: RB
authors.lastname: Gunier
authors.forename: Asa
authors.initials: A
authors.lastname: Bradman
authors.forename: Brenda
authors.initials: B
authors.lastname: Eskenazi
authors.forename: Kim G
authors.initials: KG
authors.lastname: Harley
mesh_terms: D000328:Adult; D000383:Agriculture; D001724:Birth Weight / Q000187:drug effects; D002140:California; D005260:Female; D047109:Fetal Development / Q000187:drug effects; D005333:Fetus / Q000187:drug effects*; D006801:Humans; D006842:Hydrocarbons, Brominated / Q000009:adverse effects*; D016014:Linear Models; D018811:Maternal Exposure / Q000009:adverse effects*; D011247:Pregnancy
chemical_list: D006842:Hydrocarbons, Brominated; C005218:methyl bromide