According to a new NEJM study, fireman are more likely to die from a heart attack running up the stairs to a fire, than from the fire itself.
Firefighting is known to be a dangerous occupation. What is less appreciated is that the most frequent cause of death among firefighters is heart disease rather than burns or smoke inhalation. Cardiovascular events, largely due to coronary heart disease, account for 45% of deaths among firefighters on duty.
Many people might find this conclusion surprising. Why? Because in thinking about firefighter mortality, and the riskiness of the occupation, it might seem reasonable to imagine that firefighters die so disproportionately often from fighting fires that it is the primary cause of death.
That is incorrect. It is an example of what is in behavioral finance usually called a conjunction fallacy, when it is assumed that “specific conditions are more probably than general ones”. Here is a well-known example from Dan Kahneman and Amos Tversky:
Linda is 31 years old, single, outspoken, and very bright. She majored in philosophy. As a student, she was deeply concerned with issues of discrimination and social justice, and also participated in anti-nuclear demonstrations.
Which is more likely?
- Linda is a bank teller.
- Linda is a bank teller and is active in the feminist movement.
Most people answer the question with 2), that Linda is in a bank teller and a feminist. The more probable answer, of course, is that Linda is simply a bank teller: It is more general, and therefore more likely.
It is easy to make a similar mistake in thinking about fireman mortality. Given that they fight fires, and that is a well-known hazardous occupation, you might think that the mortality risk from fire-fighting would dominate the risk from other causes of death. The trouble is, literally, that coronary disease is so widespread in the population that the incremental increased risk from it is not sufficient to make it more likely that firefighters die fighting fires than from heart attacks.