Official: Scotland sees large rise in hospital admissions for acute coronary syndrome in second year of smoking ban

Data released this week by the Scottish government show that emergency hospital admissions for acute coronary syndrome (ACS) rose sharply in the second year of the country's smoking ban.

Much was made of an apparent reduction in the number of patients being diagnosed with the life-threatening heart condition after the smoking ban came into effect in 2006, including a study published in the New England Journal of Medicine which claimed that the ban had caused emergency ACS admissions to fall by 17%.

However, official statistics show that the decline in hospitals admissions for acute coronary syndrome has been greatly exaggerated. The real decline in the first year of the smoking ban was just 7.2% - not 17% - and the rate then rose by 7.8% in the second year, cancelling out the earlier drop.

In the last 12 months before Scotland enacted its smoking ban (April 05 to March 06) there were 16,199 admissions for acute coronary syndrome*. In the second year of the smoking ban (April 07 to March 08) there were 16,212 admissions, slightly more than there had been before the legislation was enacted.

Hospitalisations for acute coronary syndrome in the last 10 years.
Source: ISD Scotland

Hospital admissions for acute coronary syndrome have been declining in Scotland for many years. The new data show that the well-publicised fall in admissions following Scotland's smoke-free legislation was in line with the existing downward trend and was significantly less steep than has previously been claimed.

The belief that the number of cases of acute coronary syndrome fell by 17% after the smoking ban stems from a study of volunteers in a selection of Scottish hospitals between 2005 and 2007. The study - 'Smoke-free Legislation and Hospitalizations for Acute Coronary Syndrome' - has since been criticised for its limited scope and for excluding data from several key months before and after the ban.

If the 2006-07 decline had really been the result of the smoke-free legislation, it would be expected for rates to remain low in subsequent years. The fact that Scottish hospitals have seen an unusually sharp rise - despite the smoking ban being rigorously enforced - suggests that whatever lay behind the 2006-07 dip, it was not the smoking ban.

Hospital data from England and Wales has failed to show a significant reduction in incidence of acute coronary syndrome since going smoke-free in 2007. This new evidence from Scotland casts serious doubts on the theory that smoking bans have a measureable impact on incidence of acute coronary syndrome.

Christopher J. Snowdon is the author of Velvet Glove, Iron Fist: A History of Anti-Smoking

* The World Health Organisation defines Acute Coronary Syndrome as being acute myocardial infarction (AMI) (ICD-10 code I21-22) and angina (ICD-10 code I20).


17.02.06: STOPIT (STudy Of Public place Intervention on Tobacco exposure) announce the decision to conduct a study designed to "test the hypothesis raised by the Montana study that a reduction in ETS [Environmental Tobacco Exposure] exposure is accompanied by a rapid reduction in the incidence of acute coronary syndrome (ACS)." The study is to be led by Dr Jill Pell.

10.9.07: Dr Pell and her team announce their findings at a conference in Edinburgh. The Scottish government marks the occasion by issuing a press release titled 'Smoking ban brings positive results' saying: "A study of nine Scottish hospitals has found a 17 per cent fall in admissions for heart attacks in the first year after the smoking ban came into force."

11.9.07: International media, including The Times, The Guardian and The Daily Mail report the news that, as the latter put it:
"Further dramatic evidence emerged last night to show that banning smoking in public reduces the rate of heart attacks. Hospital admissions for heart attacks dropped by 17 per cent in the year after the legislation was introduced in Scotland. If the pattern is repeated throughout the UK, there would be almost 40,000 fewer heart attacks a year."

14.11.07: The BBC publish an article (online) titled 'When the facts get in the way of a good story'. The author noted that data from ISD Scotland showed that the real drop in heart attacks was just 8%. He added: "What appeared to be hard medical evidence now looks more like over-hasty and over-confident research, coupled with wishful political thinking and uncritical journalism."

22.12.07: The Times includes the study in its list of 'The worst junk stats of 2007'.

30.7.08: On the eve of the study's publication, the international media report the findings again. USA Today writes: "Scotland's smoking ban appears to have prevented hundreds of heart attacks in its first year, a study shows. The number of people admitted to the hospital for heart attacks fell by 17% in the year after Scotland's smoking ban took effect in March 2006."

Tom Glynn of the American Cancer Society calls the study "virtually flawless'.

31.7.08: The study is finally published in the respected New England Journal of Medicine titled 'Smoke-free Legislation and Hospitalizations for Acute Coronary Syndrome'.

19.09.08: Velvet Glove author obtains additional hospital data under the Freedom of Information Act. Provisional data suggests that acute coronary syndrome admissions fell by 9.3% in the 12 months following the ban.

25.11.08: Scottish government quietly releases final figures for hospital admissions since the smoke-free legislation. Acute coronary syndrome admissions fell by just 7.2% in year one - in line with the long-term downward trend - before rising by 7.8% in year two.