Miscalculating health risks

The folks over at Healthcare Triage have produced another interesting video. In this one, Dr. Carroll examines the issue of accurately assessing risks to our health. Humans aren't necessarily good risk calculators. Often we obsess over infrequent dangers, and then blithely ignore more common dangers.

One good example is our fear of flying compared to our nonchalant attitude towards driving. A person is much more likely to die in a car crash (0.72 deaths per 100 million passenger miles) than a plane crash (0.01 deaths per 100 million passenger miles).

In this vein, Dr. Carroll cites a recommendation by the American Academy of Pediatrics in 2001 that mandated placing kids less than 2 years old in a safety seat in airplanes. Most parents have such young kids just sit in their laps during flights. Given the infrequency of plane crashes such a rule would save a mere 0.4 children each year according to estimates.

In the meantime, the cost of flying would rise for many families with young kids because of the requirement to purchase an extra seat. As a result, it was expected that the proposal would increase driving as a substitute for flying. Indeed, one estimate showed that the number of kids killed would actually increase (because of car accidents) if the FAA ever approved the rule (which thankfully they did not).

Another example of miscalculating health risks is how we view dangers for kids more generally. There is much media attention devoted to pediatric cancers because they are so tragic. Yet car accidents killed 895 kids aged 5-14 in 2010, and accidents in general killed 1600 kids, a figure that exceeds pediatric cancer deaths (~1350).

Furthermore, if you look at the age bracket from 10-24 (kids and young adults), the number 1 killer is accidents, number 2 is suicide, and number 3 is homicide. Each kill more than twice as many as cancer.

Finally for adults, we also tend to fixate on cancer, especially breast cancer and prostate cancer. Yet heart disease is far more prevalent (the number 1 cause of death in the U.S.) than all cancers combined. Indeed even among cancers, the toll from lung cancer is significantly larger than breast cancer in women and prostate cancer in men. Dr. Carroll points out that heart disease and lung cancer are preventable, yet we obsess over things like whether cell phones cause brain cancer (for which there is no evidence).

In summary, there are many health hazards, but people may not be good at quantitatively assessing them. It is important to prioritize these risks and focus on what is most relevant (for each individual).

Video 1. We worry about the wrong heath risks.