Background:
Tobacco Harm Reduction (THR) has become synonymous with substituting alternative tobacco products for cigarettes. However, there exists much dissension among tobacco control professionals regarding accepting harm reduction methods prolonging nicotine addiction and profiting the tobacco, e-cigarette and pharmaceutical industries. We evaluate the influence of these industries on the academic THR literature and debate.

Methods:
We undertook a comprehensive review of all peer-review papers published on the topic of tobacco harm reduction between 1992 and July 2016. Our initial search yielded 5,172 relevant hits, and after screening, we double-coded 1,067 full-text articles. Codes include the article's stand on THR (weakly or strongly pro-, anti-, or neutral/mixed), major themes, product type, country of author origin, article type (letter/commentary, RTC, longitudinal study, etc.), journal quality, and funding source. These results were analyzed in STATA.

Results:
Of the 498 articles we have coded so far, 379 were included. The results show that six percent of all articles are editorials, 36% letters or commentaries, and 21% are non-empirical articles while only 31% are original research and 6% reviews. Thirty-three percent of pro-THR articles disclosed some sort of industry funding. Of these, 30% were funded by the tobacco industry, 22% by the E-cigarette industry and 48% were funded by pharmaceutical industries.

Conclusions:
The THR debate has been influenced by scientists funded by tobacco, electronic-cigarette and surprisingly pharmaceutical industries in the favor of product substitution. Moreover, the majority of this debate is occurring over 'opinion pieces' rather than on the basis of empirical research. Thus, more robust and unbiased scientific evidence is needed to evaluate these alternative products before endorsing them for the public.