title: Preterm birth and prenatal maternal occupation: the role of Hispanic ethnicity and nativity in a population-based sample in Los Angeles, California.
abstract: OBJECTIVE
  We investigated preterm birth (PTB) in relation to maternal occupational exposure and whether effect measures were modified by Hispanic ethnicity and nativity in a population-based sample with high proportion of Hispanics.
  
  
  METHODS
  We used a case-control study (n = 2543) nested within a cohort of 58,316 births in Los Angeles County, California, in 2003. We categorized prenatal occupations using the US Census Occupation Codes and Classification System and developed a job exposure matrix. Odds ratios for PTB were estimated using logistic regression.
  
  
  RESULTS
  Odds ratios for PTB were increased for all women in health care practitioner and technical occupations, but the 95% confidence intervals included the null value; effects were more pronounced among Hispanics. We estimated elevated odds ratios for foreign-born Hispanic women in building and grounds cleaning and maintenance occupations. Shift work and physically demanding work affected births among US-born but not foreign-born Hispanics.
  
  
  CONCLUSIONS
  Hispanic women are at particular risk for PTB related to adverse prenatal occupational exposure. Nativity may moderate these effects on PTB. Maternal occupational exposures likely contribute to ethnic disparities in PTB.
authors.affiliation: Ondine S. von Ehrenstein is with the Department of Community Health Sciences, Fielding School of Public Health, University of California, Los Angeles (UCLA). Michelle Wilhem, Anthony Wang, and Beate Ritz are with the Department of Epidemiology, Fielding School of Public Health, UCLA.
authors.forename: Ondine S
authors.initials: OS
authors.lastname: von Ehrenstein
authors.forename: Michelle
authors.initials: M
authors.lastname: Wilhelm
authors.forename: Anthony
authors.initials: A
authors.lastname: Wang
authors.forename: Beate
authors.initials: B
authors.lastname: Ritz
mesh_terms: D000328:Adult; D002140:California / Q000453:epidemiology; D016022:Case-Control Studies; D054242:Emigrants and Immigrants / Q000706:statistics & numerical data; D004651:Employment / Q000706:statistics & numerical data; D005260:Female; D006801:Humans; D016015:Logistic Models; D016273:Occupational Exposure / Q000706:statistics & numerical data*; D009790:Occupations / Q000706:statistics & numerical data; D016017:Odds Ratio; D011247:Pregnancy; D047928:Premature Birth / Q000453:epidemiology* / Q000208:ethnology; D055815:Young Adult