Imperial College London


Faculty of MedicineSchool of Public Health

Honorary Research Associate



+44 (0)20 7594 3277i.bakolis Website




531Norfolk PlaceSt Mary's Campus






BibTex format

author = {Bakolis, I and Kelly, R and Fecht, D and Best, N and Millett, C and Garwood, K and Elliott, P and Hansell, A and Hodgson, S},
doi = {10.1097/EDE.0000000000000534},
journal = {Epidemiology},
pages = {810--818},
title = {Protective Effects of Smoke-free Legislation on Birth Outcomes in England: A Regression Discontinuity Design},
url = {},
volume = {27},
year = {2016}

RIS format (EndNote, RefMan)

AB - Background: Environmental tobacco smoke has an adverse impact on preterm birth and birthweight. England introduced a new law to make virtually all enclosed public places andworkplaces smoke free on July 1 2007. We investigated the effect of smoke-free legislation onbirth outcomes in England using Hospital Episode Statistics (HES) maternity data.Methods: We used regression discontinuity, a quasi-experimental study design, which canfacilitate valid causal inference, to analyse short-term effects of smoke-free legislation on birthweight, 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 Englandbetween January 1 2005 and December 31 2009. In the one to five months following theintroduction of the smoking-free legislation, for those entering their third trimester, the risk oflow 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%), pretermbirth between 4% (95% CI: 1%-8%) and 9% (95% CI: 2%-16%), and small for gestational agebetween 5% (95% CI: 2%-8%) and 9% (95% CI: 2%-15%). The impact of the smoke-freelegislation varied by maternal age, deprivation, ethnicity and region.Conclusions: The introduction of smoke-free legislation in England had an immediate beneficialimpact on birth outcomes overall, although this benefit was not observed across all age, ethnic, ordeprivation groups.
AU - Bakolis,I
AU - Kelly,R
AU - Fecht,D
AU - Best,N
AU - Millett,C
AU - Garwood,K
AU - Elliott,P
AU - Hansell,A
AU - Hodgson,S
DO - 10.1097/EDE.0000000000000534
EP - 818
PY - 2016///
SN - 1531-5487
SP - 810
TI - Protective Effects of Smoke-free Legislation on Birth Outcomes in England: A Regression Discontinuity Design
T2 - Epidemiology
UR -
UR -
VL - 27
ER -