title: A genetic instrumental variables analysis of the effects of prenatal smoking on birth weight: evidence from two samples.
abstract: There is a large literature showing the detrimental effects of prenatal smoking on birth and childhood health outcomes. It is somewhat unclear though, whether these effects are causal or reflect other characteristics and choices by mothers who choose to smoke that may also affect child health outcomes or biased reporting of smoking. In this paper we use genetic markers that predict smoking behaviors as instruments to address the endogeneity of smoking choices in the production of birth and childhood health outcomes. Our results indicate that prenatal smoking produces more dramatic declines in birth weight than estimates that ignore the endogeneity of prenatal smoking, which is consistent with previous studies with non-genetic instruments. We use data from two distinct samples from Norway and the United States with different measured instruments and find nearly identical results. The study provides a novel application that can be extended to study several behavioral impacts on health and social and economic outcomes.
authors.affiliation: Department of Health Management and Policy, College of Public Health, University of Iowa, Iowa City, IA 52242, USA. george-wehby@uiowa.edu
authors.forename: George L
authors.initials: GL
authors.lastname: Wehby
authors.forename: Jason M
authors.initials: JM
authors.lastname: Fletcher
authors.forename: Steven F
authors.initials: SF
authors.lastname: Lehrer
authors.forename: Lina M
authors.initials: LM
authors.lastname: Moreno
authors.forename: Jeffrey C
authors.initials: JC
authors.lastname: Murray
authors.forename: Allen
authors.initials: A
authors.lastname: Wilcox
authors.forename: Rolv T
authors.initials: RT
authors.lastname: Lie
mesh_terms: D000293:Adolescent; D001724:Birth Weight; D005260:Female; D005819:Genetic Markers; D020022:Genetic Predisposition to Disease / Q000453:epidemiology; D006801:Humans; D007223:Infant; D016018:Least-Squares Analysis; D008297:Male; D008425:Maternal Behavior; D009664:Norway / Q000453:epidemiology; D011247:Pregnancy; D011297:Prenatal Exposure Delayed Effects / Q000453:epidemiology*; D012907:Smoking / Q000009:adverse effects* / Q000453:epidemiology / Q000235:genetics*; D014481:United States / Q000453:epidemiology
chemical_list: D005819:Genetic Markers