After
two and a half years’ review, the FDA Center for Tobacco Products rejected Swedish
Match’s request to eliminate or revise the 30-year-old, egregiously inaccurate
warnings that are required to appear on snus products sold in the United
States.
In
2014, Swedish Match sought to:
· Remove
the warning, “This product can cause gum disease and tooth loss”;
· Remove
the warning, “This product can cause mouth cancer”; and,
· Replace
the warning, “This product is not a safe alternative to cigarettes” with this
text: “No tobacco product is safe, but this product presents substantially
lower risks to health than cigarettes.”
I
explored this issue earlier (here).
The FDA
justified its rejections in a six-page letter to the company (here) in a 115-page supporting
document (here), and subsequently in an
announcement proclaiming, “FDA Issues Science-Based Decisions on First MRTP
Applications.”
Science-based? Following is my review of the FDA’s tortured
interpretation of the scientific evidence in its decisions on the gum
disease/tooth loss and mouth cancer warnings.
Gum
Disease/Tooth Loss Warning Decision
The
agency interpreted removal of a warning as a marketing claim, obligating Swedish
Match to prove that snus was entirely without risk – a virtually impossible
task. The FDA advised, for example, that
“Omission of [the gum disease tooth loss warning] from a subset of smokeless
tobacco products indicates that unlike other smokeless tobacco products, the
eight General Snus products cannot cause gum disease or tooth loss.”
(emphasis in original).
For
this decision, the agency reviewed published studies of “dental conditions
(e.g., plaque, caries, tooth wear or tooth loss), gingivitis, gingival
recession and periodontal disease” that it claimed were related. Here are the conclusions for each of these,
with the FDA findings in bold:
·
Dental
conditions: “Overall, the dental conditions data included no studies that
evaluated tooth loss over time…The results on caries were mixed, and the only study to examine the association between
Swedish snus and tooth wear found an association. No association was seen between Swedish snus and plaque…”
·
Gingivitis:
“Overall the results of the studies on gingivitis were mixed.”
·
Gum
recession: “Overall, the only adjusted study of gingival recession to include
non-users found a significant positive association between Swedish snus and
gingival recession, and several unadjusted studies found significant
associations between Swedish snus and gingival recession, although the
direction of the association was mixed.”
·
Periodontal
disease: “Overall, nearly all of the studies which examine the association
between Swedish snus and indicators of periodontal disease (plaque, pocket
depth, attachment loss, bone loss) found no
association…”
Note
the repeated finding of “mixed,” suggesting that some studies showed a positive
association while others showed no association or a negative one. For periodontal, or gum, disease, there was
no association.
Despite
these equivocal or nil findings, the FDA concluded: “Overall, the totality of
the evidence demonstrates that the eight General snus products can cause gum
disease and tooth loss, and, correspondingly, does not support the removal of
the warning that these products can cause gum disease and tooth loss.” The FDA's decision is entirely unsupported by the "totality of evidence."
Mouth
Cancer Warning Decision
The
FDA decision on mouth cancer is based on an improper analysis of six published
studies. Peter Lee in 2010 published a
formal meta-analysis of these studies and one more (abstract here). Here are his findings for mouth cancer:
“No
overall association is seen for oropharyngeal cancer, the most studied cancer
type. For the whole population, an
increase (RR 3.1, 95% CI 1.5–6.6) seen in the Uppsala county study (Roosaar et
al., 2008), based on 11 cases, contrasts with six studies showing no increase,
the overall estimate being 0.97 (0.68–1.37). The never smoker estimate, 1.01
(0.71–1.45), based on four studies, is also null. These results are supported
by long-term follow-up of 1115 individuals with ‘‘snuff-dippers lesion’’ (Axéll
et al., 1976), which observed no oral cancers at the sites of lesions seen
initially (Roosaar et al., 2006).”
When
Lee included Roosaar with the other studies in his analysis, there was no
association of snus and mouth cancer.
The FDA basically agreed with Lee that Roosaar was the lone work that was
positive for snus and mouth cancer, but it cited this study as the sole reason
for maintaining the warning. In fact, the
FDA is saying it will ignore the broad consensus of scientific research (i.e. the "totality of evidence") if any
one study reports a positive finding.
Having
set this impossibly high bar for safer tobacco products, the FDA went further by
focusing on tobacco-specific nitrosamines in snus. Research documents that TSNAs exist in
vanishingly small concentrations in snus – about two parts per million or lower
(here), and there is
no scientific evidence directly linking TSNAs to mouth cancer. Still, the FDA cited “the presence of
nitrosamines in the products that are the subject of these applications, the
lack of a threshold dose for mouth cancer” as additional reasons to sustain the
warning. The FDA is effectively saying
that TSNAs must be reduced to zero for the warning to be removed.
The
FDA closed the door on the gum disease tooth loss warning, but it gave Swedish
Match the option of submitting a revised application for the other
warnings. It appears that the agency’s revision/amendment
pathway is designed to defeat all the but wealthiest and most determined
applicants, leaving millions of smokers and future smokers with demonstrably
false warnings against the use of safer smoke-free products.