Mortality associated with uncontrolled falls
Probably the most viewed anti-harm-reduction metaphor was on the U.S. television program, Good Morning America, in 1994, when in response to Brad Rodu and his then-novel message about ST-based harm reduction, Gregory Connolly, director of the Massachusetts [USA] Tobacco Control Program compared it to jumping from the 3rd floor rather than the 10th . More recent versions of the metaphor were uncovered by our systematic review of information about the risks of smokeless tobacco on the world wide web (described in detail in ) and subsequent ad hoc internet searchers for key phrases in online news stories and web pages. The several versions we found varied substantially, but likened smoking to falls from at least the 10th floor and ST to falls from at least the 3rd; we found numbers as high as 50 and 30.
While the danger from a fall from a given height varies substantially with the victim's age, physical abilities, landing attitude, and, especially, the surface landed upon, anyone with passing familiarity with the human body and Earth's gravity should be aware that falls from the 10th story (about 35 meters, calculating a bit under 4 meters per story in tall buildings, subtracting a bit for the window being lower than the top of the story) are almost always fatal. Thus, every version of the metaphor we have seen is absurd, with the greater distance fallen considerably worse for someone's health than smoking (or any other behavior imaginable). More importantly, the lower number grossly exaggerates the risk from ST.
Estimates of the portion of smokers whose death is substantially hastened by their smoking range as high as 1/2 in wealthy countries, down to 1/3 or 1/4. Sorting out claims of upward bias in these estimates and correcting for deaths that were not significantly hastened compared to competing causes is difficult, but these considerations argue for the lower end of this spectrum. For smokeless tobacco, even the worst-case-scenario estimates are no higher than 1/10th of that of smoking , though there is no basis in the epidemiologic evidence to suggest it is nearly that high. There is better support for the claim that it is in the range of 1/100th, perhaps 2/100ths , perhaps less . We will use the rough approximations (adequate for present purposes) of a substantially premature death rate of 1-in-4 from smoking (which might understate the contrast between smoking and ST, since most estimates are higher than this) and 1-in-400 from ST. The latter figure assumes that ST causes some mortality, despite the lack of epidemiologic evidence compellingly linking it to any specific life-threatening disease. (The limits of our science make it impossible to distinguish between risks that add to 1-in-400 from, say, 1-in-50 or 1-in-one million; fortunately, the central theses of this analysis do not depend on the exact magnitude.)
To estimate the height of falls that cause similar mortality rates, we conducted a review of the available literature on mortality rates as a function of free fall distance (we did not consider fatal slips that do not involve free fall, such as head injuries from falls in the bath or hip fractures in the elderly when falling from standing). It is surprising how little information is published on the topic. As with most of the health literature, dissimilar exposures are usually lumped together and more attention is given to the exceptional cases and outliers (e.g., very long falls that were miraculously survived) than to representative information. But we were able to identify a few useful sources of information [6–9]. The literature suggests that falls from up to the 3rd story (the rather fuzzy unit of building stories is usually used to measure height) are most always survived, with the death rate increasing sharply and approaching 100% over the next three or four stories.
Our best (admittedly somewhat rough) estimate from the available literature is that a 1-in-4 mortality rate is reached in the range of the 5th story window, while a 1-in-400 mortality rate is reached somewhere short of a 3rd story window. The first author's experience with rock climbing, and the lore thereof, tends to support the latter estimate: falls of ~9 meters onto flat ground are seldom fatal, but occasionally they are. Thus, the largest numbers that could be justified for use in the metaphor are roughly 5th and 3rd story windows for the two products.
Notice an immediate implication of this is that the 10 and 3 story comparison dramatically overstates the absolute risk reduction (risk difference) from switching from cigarettes to ST. Assuming that suicide is not actually one's goal (and tobacco users are not generally trying to kill themselves despite rhetoric to the contrary – a fact that seems to be conceded by users of the metaphor), choosing to jump from the 3rd story rather than the 10th is a very good choice indeed.
Some advocates who use higher numbers of stories are intentionally making the absurd claim that tobacco use (in any form) is virtually always fatal. By contrast, users of the metaphor who use less absurd heights like the 3rd and 10th story are typically conceding that there is a difference in risk (perhaps not realizing its magnitude), but insist that the less risky exposure is still so bad that it should not be proposed as an alternative. If we ignore the dubious premise that a major reduction in harm is not worthwhile because the residual risk is still high (consider, e.g., seatbelts), this point hinges on the absolute risk from ST, not the relative risk. For this, the 3rd story comparison is still misleading.
The above comparison of a lifetime of ST use to a 3rd story fall was based on the probability of the exposure being a contributing factor in a premature death, whenever the death might occur. A better measure of the cost of an exposure is years of potential life lost. This is important because mortality that results from a fall (or gunshot) almost always occurs almost immediately, while deaths from chronic exposures tend to occur far in the future, at an age when death from a competing cause will occur sooner. Even without correction for time preference (discounting), we estimate that for individuals in the target audience, deaths from falls cost in the order of five times as many life years as deaths from contemporarily taking up (or continuing) a lifetime course of smoking. Correcting for this, the appropriate falling distances are closer to the 4th story window or a bit lower for smoking and in the range of 2nd story for ST.
These more accurate analogies might actually be fairly useful in painting the picture for consumers. A nontrivial portion of young men (particularly the "risk takers" who are more inclined to use tobacco ) have probably jumped from a 2nd story window, but few would dare jump from the 4th. To keep the metaphor catchy and less burdened with numbers, we might suggest that the harm-reduction decision is like foregoing a jump from the top of the roof of a large house, opting to instead jump from the garage. It seems like an easy choice, as well as a useful metaphor since, again, many people have jumped from the roof of a small garage, but few could bring themselves to jump from the peak of the roof of a three story house.
It should be noted that nonfatal falls from heights often cause morbidity, but we make no attempt to incorporate this into our calculation of comparative mortality. There is a fair probability of injury from a non-fatal 2-story fall, making the prospect of such a fall intimidating, and so the analogy remains an overstatement of the morbidity risk when mortality risk is equalized. Thus, even the 2nd and 4th stories tends to overstate the risk from ST and possibly from smoking (though the latter is known to cause various non-fatal major morbidities at a high rate, so that contrast is not so large).
Mortality from self-inflicted gunshot wounds
It is immediately obvious that the gunshot metaphor is absurd for the same reasons as the 10-vs-3 version of the jumping metaphor: If someone was faced with the choice of shooting himself in the head and ..., well, almost anything else, really, but in particular shooting himself in the foot or leg, the latter option is quite obviously better from a health outcomes perspective. Again, the attempt to ridicule harm-reduction actually makes a pretty good case for it.
Beyond that, however, the analogy fails. Mortality risk from self-inflicted gunshot wounds to the head dwarfs that from smoking, while foot wounds, though they have a low mortality rate, have a high probability of permanent debilitating orthopedic damage, a risk absent in tobacco use. A penetrating gunshot wound to the upper leg stands a nontrivial chance of being fatal, greater than the risk from ST.
We hesitate to try to provide a correction, like the above corrected height of fall, concerning where in one's body to inflict a gunshot wound to cause a certain probability of mortality. Self-inflicted gunshot wounds unambiguously evokes attempted suicide. The psychological health problems that lead to such behaviors make it seem inappropriate to either use this as a whimsical attack on harm reduction, or to try to deconstruct the joke in any further detail. (Though it is interesting to note that self-administration of nicotine is thought to provide relief from certain psychological and neurodegenerative diseases that could lead to self-inflicted trauma if untreated [11, 12].) Moreover, blithe references to shooting oneself seem particularly inappropriate with hundreds of thousands of members of the main target population (most of the rhetoric originates in the USA and is directed at adolescents) are experiencing the horrors of pointless military combat and its various deadly tools, with quite a few committing suicide following the experience [13–15]. (As an aside: it is likely that tens of thousands of young men and women took up smoking during their recent combat experience, increasing the importance of harm reduction.)
Our research uncovered a handful of less common metaphors, which have either fallen from favor or never caught on. Getting hit by a car rather than a truck (found in a few dental health websites, attributed to a single source ) is another case where there is no appreciable difference in the risks from the exposures ceteris paribus, though the details of the collision are so obviously important that the metaphor is hopelessly muddled. Shooting oneself with one type of military weapon rather than another (e.g., a rifle rather than an Uzi ) also seems to have not caught on. This one likely failed to gain popularity because the location of the wound is paramount, and the level of detail makes it enough more distasteful so that even those who like the generic gunshot metaphor might avoid it.
One of the more bizarre metaphors we found in our research is that switching to ST is like driving at 100 miles per hour rather than 140 miles per hour . The mortality rate from taking a car up to one of these speeds is quite trivial; people do it rather frequently. Perhaps the authors meant driving that speed all the time, but this seems prohibitively challenging. The reason this one is worth mentioning is because it reminds us that people who use tobacco are well known to be more likely to have a variety of risky and unhealthy behaviors, such as habitually driving dangerously. Every time health advocates expend effort and use up people's limited attentiveness to health matters trying to dissuade them from using ST, it not only reduces the prospect of harm reduction, but reduces the potential to affect other behaviors that are much riskier.