5770 fewer deaths from coronary heart disease occurred in 2010 than would be expected if the 2000 mortality rates had persisted (8042 rather than 13 813). This reflected a 43% fall in coronary heart disease mortality rates (from 262 to 148 deaths per 100 000). Improved treatments accounted for approximately 43% (95% confidence interval 33% to 61%) of the fall in mortality, and this benefit was evenly distributed across deprivation fifths. Notable treatment contributions came from primary prevention for hypercholesterolaemia (13%), secondary prevention drugs (11%), and chronic angina treatments (7%).
Risk factor improvements accounted for approximately 39% (28% to 49%) of the fall in mortality (44% in the most deprived fifth compared with only 36% in the most affluent fifth). Reductions in systolic blood pressure contributed more than one third (37%) of the decline in mortality, with no socioeconomic patterning.
Smaller contributions came from falls in total cholesterol (9%), smoking (4%), and inactivity (2%).
One contribution is conspicuous by its absence. You may recall the widely circulated claim that was made 2007:
Smoking ban brings big cut in heart attacks in Scotland, study finds
The number of people being taken to hospital with heart attacks in Scotland has fallen significantly since the smoking ban was introduced, the most detailed study into the impact of the measure has revealed.
Researchers found a 17% drop in the number of people admitted for heart attacks in the year since the ban came into force, compared with an average 3% reduction a year over the previous decade.
So where does the smoking ban rank in the list of factors that led to the millennial drop in heart disease mortality?
Nowhere. It doesn't get a mention. Smoking is listed as one of the "behavioural risk factors [that] made a modest contribution to deaths prevented or postponed" and the authors estimate that the four percentage point decline in smoking rates "contributed approximately 210 fewer deaths or 4% [of the overall decline]". But despite considering "a comprehensive range of risk factors", the smoking ban doesn't feature at all.
It's not difficult to see why. As I have pointed out ad nauseum, all the official data from ISD Scotland shows that rates of heart attack, angina and heart disease were completely unaffected by smoking ban (which came into force in March 2006). The graphs below show deaths from heart attacks (acute myocardial infarction) and total mortality from heart disease. (See here for the data. Note that ISD Scotland says that the increase in heart attacks from 2008/09 is "likely to be due to the introduction of more sensitive tests for diagnosis, meaning that more cases were now correctly diagnosed as heart attacks". Fortunately, we do not need these later figures to see what effect the March 2006 smoking ban had on heart attacks, ie. none.)
The claim that there was a steep and immediate decline in heart attack incidence after the ban is - and always has been - a lie. It now seems clear that the whole 'heart miracle' hypothesis came about as a result of publication bias. Hence, it merits no discussion by anyone wants to understand the reasons why heart disease mortality has been steadily declining over a decade or more.
Similarly, when a 2012 BMJ study looked at the reasons why heart attack mortality fell by half in England between 2002 and 2010, it made no mention of the 2007 smoking ban despite the earlier claim that "the ban on smoking in public has led to a dramatic fall in heart attack rates". That's because there never was a "dramatic fall in heart attack results".
|Graph from the BBC|
This illustrates the difference between health research and 'public health' research. 'Public health' research is generally policy-oriented junk science created for maximum media coverage whereas health research is designed to help clinicians understand what works and what doesn't. Health researchers tolerate the publication of 'public health' quackery because it is, they believe, all for a good cause, but incorporating it into their own work would invite mockery from colleagues and would amount to borderline medical negligence.
For their part, the 'public health' researchers have usually achieved their political goals by the time real evidence is published and so they cross their fingers and hope that nobody notices. They are rarely disappointed.