Air pollution is a bigger trigger of heart attacks in the population than physical exertion, alcohol and taking cocaine, a study has shown. On an individual basis, cocaine raises the risk of a heart attack 23 times, says a study published in the Lancet.
But far more people are exposed to traffic fumes and factory emissions than cocaine so air quality is a far more important population-wide threat.
Scientists looked at "final straw" risk factors for triggering heart attacks, rather than underlying causes of heart disease. The highest risk factor was traffic exposure (7.4%), followed by physical exertion (6.2%) and alcohol (5%), coffee (5%), and higher levels of small air pollutant particles known as PM10s (4.8%).
Other risk factors included negative emotions, with a PAF of 3.9%, anger (3.1%), eating a heavy meal (2.7%), positive emotions (2.4%) and sexual activity (2.2%).
Air pollution triggers 5-7% of heart attacks in the population, they say. Cocaine accounts for just 0.9% of all heart attacks.