As a pathologist, I have studied how human cells are altered
by disease; with colleagues, I have explored in the laboratory how cancer cells
behave and respond to various treatments.
A single human disease can involve thousands of changes in the
arrangement and interaction of the 10,000 different kinds of
molecules present in each cell.
While I have profound respect for those conducting
legitimate research to expand our understanding of human biology, diseases and
their treatment, I am dismayed by the recent spate of laboratory studies in
which researchers expose cells living in artificial environments to e-cigarette
liquids. The liquids invariably produce
measurable effects, which lead to claims that e-cigarettes cause myriad
diseases. These claims are further
exaggerated in press releases and sensationalized media coverage.
E-cigarette consumers – vapers – need to understand that
what happens in these lab experiments does not necessarily mirror cellular
action in humans. Human cells nurtured
in labs’ artificial environments are exquisitely delicate; even under perfect conditions,
it is exceedingly difficult to keep them alive – a minor change in the
environment can skew an experiment and even kill the cells.
Humans are far more resistant to small doses of chemicals
than are cells in a petri dish. Famed
biologist Bruce Ames wrote in 2000, “Humans have many natural defenses that
buffer against normal exposures to toxins…Examples of general
defenses include the continuous shedding of cells exposed to toxins. The
surface layers of the mouth, esophagus, stomach, intestine, colon, skin and
lungs are discarded every few days; DNA repair enzymes, which repair DNA that
was damaged from many different sources; and detoxification enzymes of the
liver and other organs.” (abstract here).
Ames made prescient comments about excessive regulation based
on laboratory experiments: “Regulatory efforts to reduce low-level human
exposures to synthetic chemicals because they are rodent carcinogens are
expensive; they aim to eliminate minuscule concentrations that now can be
measured with improved techniques. These
efforts are distractions from the major task of improving public health through
increasing scientific understanding about how to prevent cancer (e.g., what
aspects of diet are important), increasing public understanding of how
lifestyle influences health, and improving our ability to help individuals
alter their lifestyles. Why has the government focused on minor
hypothetical risks at huge cost? A recent article in The Economist had a
fairly harsh judgment:
“‘Predictions of
ecological doom, including recent ones, have such a terrible track record that
people should take them with pinches of salt instead of lapping them up with
relish. For reasons of their own, pressure groups,
journalists and fame-seekers will no doubt continue to peddle ecological
catastrophes at an undiminishing speed… Environmentalists are quick to accuse
their opponents in business of having vested interests. But their own incomes, their fame and their
very existence can depend on supporting the most alarming versions of every
environmental scare. ‘The whole aim of
practical politics’ said H.L. Mencken, ‘is to keep the populace alarmed — and hence clamorous to be led to safety —
by menacing it with a series of hobgoblins, all of them imaginary.’ Mencken’s forecast, at least, appears to have
been correct.’
“Aaron Wildavsky discusses worst-case risk assessment in his
book But Is It True: A Citizen’s Guide to Environmental
Health and Safety Issues: ‘We should
be guided by the probability and extent of harm, not by its mere possibility. The search for possibilities is endless and it
trivializes the subject. There is bound
to be great diversion of resources without reducing substantial sources of
harm. Consternation is created but
health is not enhanced…Weak causes are likely to have weak effects. Our search
should be for strong causes with palpable effects, like cigarette smoking. They are easier to find and their effects are
much more important to control…The past
necessity of proving harm has been replaced by a reversal of causality: now the
individuals and businesses must prove that they will do no harm. My
objection to this…is profound: our liberties are curbed and our health is
harmed.’” (emphasis mine)
If lab studies were the standard for evaluating consumer
products, then medicines already on the market would be in big trouble: One
study found that half of marketed pharmaceuticals demonstrate cancer-producing
properties in lab studies (here). A Journal
of Pharmacology report terms standard human cell lab tests (genotoxicity
assays) “misleading,” “irrelevant” or “false.” (here)
E-cigarette liquids are being vilified through such tests. Vapers should not be fooled by the irresponsible
transformation of weak cause-and-effect analyses into hypothetical illnesses. Largely harmless products can be portrayed
quite readily as dangers – coffee, for example , has not been linked to any
serious disease, but one could point to lab studies showing that coffee kills
cells (here and here) and promotes
cancers (here). These claims would have about as much
scientific credibility as the current claims against e-cigarettes.