In September 2007, the Scottish government declared that the country’s year-old smoking ban had led to a dramatic fall in hospital admissions for acute coronary syndrome (ACS), which includes heart attacks and angina. Health officials argued that these figures vindicated their illiberal anti-smoking policy. But data released this week cast serious doubts on the theory that smoking bans have a measurable impact on ACS.
The Scottish government announcement was based on a study led by Professor Jill Pell of the University of Glasgow, which was presented at a conference on the smoking ban in Edinburgh and later published in the New England Journal of Medicine. According to the study, admissions for ACS had fallen by 17 per cent in the first year of the ban. Pell told BBC News: ‘The primary aim of smoking bans is to protect non-smokers from the effects of passive smoking. Previous studies have not been able to confirm whether or not that has been achieved. What we were able to show is that among people who are non-smokers there was a 20 per cent reduction in heart attack admissions. This confirms that the legislation has been effective in helping non-smokers.’
As newspapers reported at the time, if the pattern were repeated throughout the UK, there would be almost 40,000 fewer heart attacks a year. Pell was certainly very keen to talk up the effects of the Scottish legislation: ‘The ban on smoking in public places provides everyone in Scotland with effective protection from the harmful effects of second-hand smoke and was a courageous move taken by the Scottish parliament. That decision has now been shown to be paying dividends for everyone living in Scotland.’
However, not everyone was convinced by the study. In November 2007, routine data from Scottish hospitals suggested the fall was much smaller – about eight per cent. And, as Michael Blastland pointed out in an article for BBC News, there has been a long-term fall in acute heart cases, which suggests smoking ban had an even smaller effect than first assumed. Blastland also noted that even bigger drops in cases had been reported in earlier years: ‘This seems to demonstrate significant variability around the trend, suggesting that last year’s eight per cent drop might even be the result of chance. It is conceivable, although perhaps unlikely, that the smoking ban had no effect at all. The figures could be a result of no more than the ordinary ups and downs of statistical variation from one year to the next.’
The latest figures suggest a rise of 7.8 per cent in the second year of the ban, cancelling out the earlier drop. Putting the full picture together, we find that in the last 12 months before Scotland enacted its smoking ban (April 2005 to March 2006), there were 16,199 admissions for acute coronary syndrome. In the second year of the smoking ban (April 2007 to March 2008) there were 16,212 admissions – slightly more than there had been before the legislation was enacted.
Pell’s conclusion that cases of acute coronary syndrome fell by 17 per cent 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 Hospitalisations for Acute Coronary Syndrome – was described as ‘virtually flawless’ by Tom Glynn of the American Cancer Society, but has since been criticised for its limited scope and for excluding data from several key months before and after the ban.