Short term impact of smoke-free legislation in England: retrospective analysis of hospital admissions for myocardial infarctionBMJ 2010; 340 doi: http://dx.doi.org/10.1136/bmj.c2161 (Published 08 June 2010) Cite this as: BMJ 2010;340:c2161
- Michelle Sims, research officer12,
- Roy Maxwell, senior analyst 3,
- Linda Bauld, professor of social policy24,
- Anna Gilmore, clinical reader in public health12, clinical senior lecturer5
- 1School for Health, University of Bath, Bath BA2 7AY
- 2UK Centre for Tobacco Control Studies, University of Bath, Bath
- 3South West Public Health Observatory, Bristol BS8 2RA
- 4Department of Social and Policy Sciences, University of Bath, Bath
- 5London School of Hygiene and Tropical Medicine, London WC1E 7HT
- Correspondence to: A Gilmore, School for Health, University of Bath, Bath BA2 7AY
- Accepted 11 February 2010
Objective To measure the short term impact on hospital admissions for myocardial infarction of the introduction of smoke-free legislation in England on 1 July 2007.
Design An interrupted time series design with routinely collected hospital episode statistics data. Analysis of admissions from July 2002 to September 2008 (providing five years’ data from before the legislation and 15 months’ data from after) using segmented Poisson regression.
Population All patients aged 18 or older living in England with an emergency admission coded with a primary diagnosis of myocardial infarction.
Main outcome measures Weekly number of completed hospital admissions.
Results After adjustment for secular and seasonal trends and variation in population size, there was a small but significant reduction in the number of emergency admissions for myocardial infarction after the implementation of smoke-free legislation (−2.4%, 95% confidence interval −4.06% to −0.66%, P=0.007). This equates to 1200 fewer emergency admissions for myocardial infarction (1600 including readmissions) in the first year after legislation. The reduction in admissions was significant in men (3.1%, P=0.001) and women (3.8%, P=0.007) aged 60 and over, and men (3.5%, P<0.01) but not women (2.5% P=0.38) aged under 60.
Conclusion This study adds to a growing body of evidence that smoke-free legislation leads to reductions in myocardial infarctions. It builds on previous work by showing that such declines are observed even when underlying reductions in admissions and potential confounders are controlled for. The considerably smaller decline in admissions observed in England compared with many other jurisdictions probably reflects aspects of the study design and the relatively low levels of exposure to secondhand smoke in England before the legislation.
We are grateful to the Association of Public Health Observatories, in particular Bobbie Jacobson, Paul Brown, and Davidson Ho for their support, and to the Health Protection Agency for providing the flu data. The HES data were made available by the NHS Health and Social Care Information Centre. We also thank Alan Kelly and Stephen Babb for their comments on early drafts of this paper.
Contributors: AG developed the research proposal and is the principal investigator. AG and MS planned the analysis, drafted and edited the paper, and are guarantors. MS undertook the analysis. RM contributed to data preparation, study design, and editing of the paper. LB contributed to the funding proposal, drafting, and editing of the paper.
Funding: This work was undertaken by the University of Bath, which received funding from the Department of Health’s Policy Research Programme. The views expressed in the publication are those of the authors and not necessarily those of the Department of Health. AG is supported by a Health Foundation Clinician Scientist Fellowship. MS, LB, and AG are members of the UK Centre for Tobacco Control, a UKCRC Public Health Research: Centre of Excellence. Funding from the British Heart Foundation, Cancer Research UK, Economic and Social Research Council, Medical Research Council and the Department of Health, under the auspices of the UK Clinical Research Collaboration is gratefully acknowledged. The funders played no role in the study design, analysis, and interpretation of data nor in the writing of the report or the decision to submit the article for publication.
Competing interests: All authors have completed the Unified Competing Interest form at www.icmje.org/coi_disclosure.pdf (available on request from the corresponding author) and declare that all authors had: (1) Financial support for the submitted work as detailed above; (2) No financial relationships with commercial entities that might have an interest in the submitted work; (3) No spouses, partners, or children with relationships with commercial entities that might have an interest in the submitted work; (4) No non-financial interests that may be relevant to the submitted work.
Ethical approval: The study was approved by the University of Bath School for Health’s school research ethics approval panel (SREAP).
Data sharing: No additional data available.
This is an open-access article distributed under the terms of the Creative Commons Attribution Non-commercial License, which permits use, distribution, and reproduction in any medium, provided the original work is properly cited, the use is non commercial and is otherwise in compliance with the license. See: http://creativecommons.org/licenses/by-nc/2.0/ and http://creativecommons.org/licenses/by-nc/2.0/legalcode.