Protective Effects of Smoke-free Legislation on Birth Outcomes in England: A Regression Discontinuity Design

Title: Protective Effects of Smoke-free Legislation on Birth Outcomes in England: A Regression Discontinuity Design
Author(s): Bakolis, I
Kelly, R
Fecht, D
Best, N
Millett, C
Garwood, K
Elliott, P
Hansell, A
Hodgson, S
Item Type: Journal Article
Abstract: Background: Environmental tobacco smoke has an adverse impact on preterm birth and birth weight. England introduced a new law to make virtually all enclosed public places and workplaces smoke free on July 1 2007. We investigated the effect of smoke-free legislation on birth outcomes in England using Hospital Episode Statistics (HES) maternity data. Methods: We used regression discontinuity, a quasi-experimental study design, which can facilitate valid causal inference, to analyse short-term effects of smoke-free legislation on birth weight, low birth weight, gestational age, preterm birth and small for gestational age. Results: We analysed 1,800,906 pregnancies resulting in singleton live-births in England between January 1 2005 and December 31 2009. In the one to five months following the introduction of the smoking-free legislation, for those entering their third trimester, the risk of low birth weight decreased by between 8% (95% CI: 4%-12%) and 14% (95% CI: 5%-23%), very low birth weight between 28% (95% CI: 19%-36%) and 32% (95% CI: 21%-41%), preterm birth between 4% (95% CI: 1%-8%) and 9% (95% CI: 2%-16%), and small for gestational age between 5% (95% CI: 2%-8%) and 9% (95% CI: 2%-15%). The impact of the smoke-free legislation varied by maternal age, deprivation, ethnicity and region. Conclusions: The introduction of smoke-free legislation in England had an immediate beneficial impact on birth outcomes overall, although this benefit was not observed across all age, ethnic, or deprivation groups.
Publication Date: 13-Jul-2016
Date of Acceptance: 25-Dec-2015
ISSN: 1531-5487
Publisher: Wolters Kluwer Health, Inc.
Start Page: 810
End Page: 818
Journal / Book Title: Epidemiology
Volume: 27
Issue: 6
Sponsor/Funder: National Institute for Health Research
Funder's Grant Number: RP_2014-04-032
Copyright Statement: © 2016 Wolters Kluwer Health, Inc. All rights reserved. This is the accepted version of an article published in final form at
Keywords: Epidemiology
Public Health And Health Services
Publication Status: Published
Appears in Collections:Faculty of Medicine
Epidemiology, Public Health and Primary Care

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