Memorandum by British American Tobacco
THE TOBACCO INDUSTRY AND THE HEALTH RISKS
OF SMOKING (TB 28)
COMPENSATION
182. British American Tobacco has participated
from the outset in the wider scientific community's attempt to
understand smoking behaviour, and especially the phenomenon of
compensation. Among many other initiatives, British American Tobacco
hosted one of the first international conferences on smoking behaviour,
held at Chelwood in England in 1977. The papers given at the conference,
by both British American Tobacco researchers and guest speakers,
covered a range of subjects, including the effects of smoking
on the central nervous system, methodology in smoking behaviour
research, the importance of nicotine in smoking motivation, and
the phenomenon of compensation. The conference was attended by
more than 50 scientists from all over the world, representing,
for example, hospitals in the USA, Canada and the UK, the Universities
of Oxford, Cambridge, Southampton, Newcastle and Reading, the
London School of Economics, the Medical Research Council's Neuropharmacological
Unit, and the Institute of Psychiatry. The audience included the
Scientific Secretary to the ISCSH. At the conference, British
American Tobacco scientists laid out an important cross-section
of the internal smoking behaviour research programme, including
details of methodology and instruments used. The proceedings of
the conference were published (Thornton, RE "Smoking Behaviour",
Churchill Livingstone, Edinburgh, 1978), and were cited by the
US Surgeon General in his 1981 and 1988 reports ("The Health
Consequences of Smoking: The Changing Cigarette", p 180,
184, 1981; "The Health Consequences of Smoking: Nicotine
Addiction", p 58, 1988).
183. As a result of its own research, the
joint projects with Dr Russell, Dr Stepney of Cambridge University,
and others, and its review of the published literature, British
American Tobacco has formed views on the duration and extent of
compensatory behaviour, and the product characteristics which
underpin it.
184. It is clear that compensation does
occur, but that, as Professor Wald observed (para 174), despite
compensation, smokers receive less tar on average when switching
to a lower tar cigarette. The extent to which compensation occurs,
and how long it lasts, are issues which are less well understood.
Much of the early evidence for compensation came from experimental
or observational brand-switching studies from a period when smokers
of High or Middle tar products increased their average puff volume
when trying to adjust down from products in the tar bands to which
they were accustomed. In the experimental studies, the switching
was often not voluntary. In both types of study, it is likely
that smokers were often switching away from a product they preferred.
In addition, almost all of these studies were relatively short-term
(ie the observations took place over a period of weeks rather
than months or years).
185. The evidence suggests that increasing
the number of cigarettes consumed, blocking of ventilation holes
and increasing inhalation depth, are not common compensation mechanisms.
Compensation seems generally to take place at the puffing stage
(ie through larger puff volumes).
186. Even today, little is known about the
duration of compensatory behaviour. Few published studies have
tracked smokers who have changed to brands with different tar
levels for even a year. The limited evidence of which we are aware,
suggests that switched smokers either revert gradually to their
former, non-compensatory behaviour (which results in lower overall
intake of smoke), or change again to a brand which they prefer
and which does not require the extra "effort" of taking
larger puffs (which may or may not result in lower intake).
187. It should also be noted that many current
adult smokers have been accustomed to low tar brands since relatively
early in their smoking history. Many do not exhibit a preference
for old, high taste and strength-style products, and observational
evidence is that they do not seem to exhibit characteristic over
smoking seen in typical compensatory behaviour; that is to say,
puff volume does not appear to correlate with tar or nicotine
yield. This implies either that many smokers of low tar brands
have never "compensated" or that, if they once did,
they have now stopped. However, this is an area where further
research is needed.
188. Similarly, the question of what provokes
compensatory behaviour is still the subject of investigation.
Many adhere to the hypothesis that smokers compensate either to
regulate their nicotine uptake over a period of time, or to derive
from the lower delivery product the nicotine "peaks"
to which they were formerly accustomed. However, there is accumulating
evidence that compensatory behaviour is primarily stimulated by
reductions in other smoke components which are responsible for
the taste and body of the smoke, and its sensory effects at the
puffing stage. Another factor may be the draw resistance associated
with lower yield products. These views are consistent with a recent
review of the scientific literature (Scherer G, "Smoking
Behaviour and Compensation: A Review of the Literature,"
Psychopharmacology, 145:1, 1999).
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