The Results of Studies on the Health Effects of Smokeless Tobacco Funded by Tobacco Companies: A Meta-Analysis

Abstract

Background: This study aimed to examine the health impact of the use of smokeless tobacco in the context of research conducted by scholars with financial and organizational connections with tobacco companies. The study findings were intended to construct a foundation for regulating smokeless tobacco by contrasting such studies with investigations by researchers who did not declare any shared interest with tobacco companies in terms of funding or affiliation. Methods: This systematic literature review established operational definitions to identify connections between researchers and tobacco companies. The affiliations of authors with leading tobacco companies were scrutinized using the Truth Tobacco Industry Documents. Internal documents released by tobacco companies were reviewed to ascertain whether any author of the relevant reviewed literature had received financial backing, participated in funding initiatives, or was an erstwhile employee of tobacco companies. Results: The findings revealed that the reviewed studies reported a relatively high incidence rate of pancreatic cancer among smokeless tobacco users. However, studies by authors without competing interests concluded that smokeless tobacco users were more likely to develop cardiovascular diseases, lung cancer, as well as pancreatic cancer. In particular, a statistically significant difference was noted depending on the presence or absence of competing interest in the results reported for cardiovascular diseases, myocardial infarctions, and lung cancer. Conclusion: Tobacco companies conduct their own research; they also fund various research centers and colleges to construct evidence that would be advantageous to their interests. Smokeless tobacco manufacturers rely on such evidence to promote their products as safe. Therefore, due attention must be paid to scholarly references to such findings and the inferences drawn from them.