In a recent article in Nicotine and Tobacco Research, Does Dual Use Jeopardize the Potential Role of Smokeless Tobacco in Harm Reduction?
Kimberly Frost-Pineda et al investigate and discuss the ramifications of dual use (link to abstract).
(First of all to get the terminology clear, dual use refers to the same individual sometimes smoking and sometimes using smokeless tobacco. At exactly the same time is quite unusual unless you are Babe Ruth who was reputed to not only chew tobacco and smoke at the same time but to do so while eating and downing liquor.)
Though dual use itself has never been a great concern to THR advocates, it has been seen as a strong argument by opposing factions for a number of reasons. They have argued that promoting smokeless tobacco as means to quit smoking would not only make quitting less likely but would increase the risk by increasing the overall exposure to tobacco.
(I will not discuss the first in any detail except to say that this particular point hinges partly on the idea that smoking restriction regulations lead to quitting because smokers have few places and times in which to comfortably smoke. At some point, the annoyance outweighs the pleasure and the person quits. Of course, the original impetus for non smoking spaces was to reduce the health risk to non smokers but now using bystander-friendly e-cigarettes or smokeless tobacco in these spaces is considered a “loophole”. In other words, people can and will use these products to get nicotine even when they cannot smoke which lessens the impact (or annoyance) of no smoking spaces. Oddly enough, in the case of smokeless tobacco, companies cannot actually encourage switching by saying it is a safer product but are restricted to promoting it as a temporary substitution, so smokers are actually getting the message that the most proper use of these products is to maintain the original more harmful habit.)
But to the meat of the matter.
Does dual use which might be more tobacco use overall result in greater risk? Frost-Pineda et al looked at many studies which calculated and reported on the disease risks associated with types of tobacco use (current and former smoking only, smokeless only, dual and no use) and compared the risk estimates associated with current dual use with current smoking only. To make a long story short, dual use was found to result in lower disease risk than smoking only.
There are good basic reasons for why this is the case. Smokeless tobacco use is very low risk and smoking is very high risk and whenever you use smokeless instead of smoking, overall risk decreases. If the user is aware of the risk differences and they are somewhat risk averse, they may start using smokeless even at times when smoking was possible. In some cases that will result in switching over entirely.
The point here is that even if total switching does not occur, dual use is a step in the right direction. As well, the data appear to indicate that a dual user is more likely to quit smoking than a cigarettes only user. It is not as harm reducing as supplanting smoking entirely but it reduces harm in the short and long term and therefore should not form the basis of any argument against promoting smokeless tobacco as part of harm reduction policy.
-Paul L. Bergen