Ongoing discussion and debates among primary scientific researchers of the effects of snus use on life expectancy appear to indicate a significant increase in life expectancy among persons who previously smoked tobacco and switch to snus, depending on the age of the persons who switch, even when it is assumed that 100% of the risk of cardiovascular diseases among smokers transfers to snus users. This study determined that "for net harm to occur, 14-25 ex-smokers would have to start using snus to offset the health gain from every smoker who switched to snus." It is also noted, in the correspondence seen in the previous citation, that concerns about the effect of marketing by the tobacco industry, as influenced by the results of these scientific studies, is of primary concern to many researchers in the field, including the risk of emboldening the industry to attempt to increase snus sales among young people and promote dual-use of snus and smoked tobacco, and the use of medical nicotine, rather than snus, can better target at-risk populations, given better access and pricing.