There is already strong evidence that studies funded by the tobacco industry (and other industries) are more likely to support industry positions on e-cigarettes and harm reduction.
A new study from Japan shows the same thing for heated tobacco products (HTP).
Suzuki, H.; Aono, N.; Zhang, Y.; Yuri, K.; Brou, M.A.M.B.E. Takemura, S.; Higashiyama, A.; Tabuchi, T.; Fujiyoshi, A., “Comparison of publications on heated tobacco products with conventional cigarettes and implied desirability of the products according to tobacco industry affiliation: a systematic review,” published in Nicotine and Tobacco Research, examined the association between tobacco industry affiliation and conclusions in 134 studies published by 2017. The industry was responsible for creating most of the relevant literature, with two-thirds of the studies (64.9%) affiliated with the tobacco industry. More important, 56.3% (49/87) of the industry-affiliated studies concluded HTPs were more desirable than cigarettes versus 19.1% (9/47) of nonindustry-affiliated studies.
A real strength of this paper is that the (Japanese) authors not only searched the English language scientific literature, but also the Japanese language literature. This is important because HTP, led by Philip Morris’ IQOS, have been widely available in Japan and several other Asian countries much longer than in the US and other English-speaking countries.
Another important point they make is that none of the studies assessed clinical disease outcomes, but rather focused on biomarkers and other indirect measures. As they note,
The risks of using surrogate outcomes in health risk assessment have been well described as such, outcomes are not necessarily linked to clinically important conditions in human beings. A great deal of uncertainty remains considering the health risk assessment of HTPs, such as whether a reduction in the toxic substances also causes a reduction in clinically adverse outcomes to the same extent. [citations omitted]
This large and growing case about pro-industry biases in industry-affiliated research poses particular problems for regulatory agencies, like the FDA, who make decisions based in information submitted by industry.
The National Academies of Science, Engineering and Medicine 2023 report Sponsor Influences on the Quality and Independence of Health Research, which sums up a meeting where experts discussed how scientific studies funded by industry or conducted by an author with a conflict of interest consistently report results more favorable to industry or the sponsor than studies free from bias. The report finds similar patterns across research areas including tobacco, nutrition, and pharmaceutical industries.
Here is the abstract of the new paper:
Introduction: Heated tobacco products (HTPs) have been advertised as “reduced-harm” tobacco products compared to conventional cigarettes (CC); however, no direct evidence supporting HTPs being desirable for human health exists. A previous systematic review reported that evidence on HTPs published in 2017 or earlier was primarily drawn from industry-related papers. We aimed to investigate whether tobacco industry-affiliated studies are more likely to conclude that HTPs are more desirable than CC.
Methods: PubMed and Ichushi-Web were searched up to March 15, 2022, for studies on HTPs published in 2017 or after. We selected studies that assessed any measures of HTPs and CC, including secondary analyses using gray literature in English or Japanese. We excluded review articles except for a meta-analysis that met the aforementioned criteria. Data on the authors’ affiliations, grant, conflict of interest, category of research subjects, and interpretation were extracted. Research members in two groups independently assessed the papers; discrepancies were solved by discussion between the groups.
Results: Overall, 134 studies met the criteria. Eighty-seven (64.9%) of them were affiliated with the tobacco industry. Of the 134 studies, 56.3% (49/87) of the industry-affiliated studies versus 19.1% (9/47) of nonindustry-affiliated studies concluded that HTPs were more desirable than CC (p < .01). No study investigated clinically relevant outcomes, such as disease occurrence.
Conclusions: Publications on HTPs in the biomedical literature from January 2017 to March 2022 were dominated by tobacco industry-affiliated studies. More than half of them concluded that HTPs were more desirable than CC compared to independent studies.
Implications: Tobacco industry advertises HTPs as “reduced-harm” tobacco products compared to CC. HTP users tend to consider HTPs as alternative tobacco products less harmful than CC (ie, products for “harm reduction”). Our results demonstrated that papers written by tobacco industry-affiliated authors concluded that HTPs were more desirable than CC compared to papers by independent authors. However, all their judgments were based on surrogate outcomes. Surrogate outcomes are not necessarily linked to clinically relevant outcomes such as disease occurrence. Further studies on HTPs using clinically relevant outcomes are warranted by independent authors from tobacco industry.
The full citation is: Suzuki H, Aono N, Zhang Y, Yuri K, Bassole Epse Brou MAM, Takemura S, Higashiyama A, Tabuchi T, Fujiyoshi A. Comparison of Publications on Heated Tobacco Products With Conventional Cigarettes and Implied Desirability of the Products According to Tobacco Industry Affiliation: A Systematic Review. Nicotine Tob Res. 2023 Nov 10:ntad205. doi: 10.1093/ntr/ntad205. Epub ahead of print. PMID: 37950902. It is available here.
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