Written evidence submitted by the Sheffield
Addiction Research Group at the University of Sheffield (AG 11)|
1. What evidence are Government's guidelines
on alcohol intake based on, and how regularly is the evidence
1.1 The evidence base for alcohol intake guidelines
is primarily epidemiological studies relating alcohol consumption
at different levels to the risk of various harms which have been
shown to result from drinking. Such studies can be used to identify
at what level of alcohol consumption the risk of harm begins to
increase. The evidence base addresses both individual harms and
"all cause mortality" (the total risk of premature death
from any harm).
1.2 Different measures of risk
1.2.1 There are different ways of reporting the
risk associated with levels of alcohol consumption. Amongst the
most common ways are the use of absolute risk and relative risk
measures. The absolute risk of experiencing harm is the simple
probability that harm will be experienced at a given level of
consumption. The relative risk is the probability of experiencing
harm as a proportion of the risk associated with a reference category
1.2.2 Both approaches have advantages and drawbacks.
The absolute risk approach gives a clear indication of the level
of risk associated with a particular behaviour (eg drinking x
units a day is associated with a y% risk of premature mortality).
However, it gives no comparison of how much greater this risk
is than that experienced by non-drinkers. This can produce counterintuitive
results whereby an individual belonging to a low risk group may
perceive their high levels of consumption to be less harmful than
if they were in a high risk group with lower consumption. Moreover,
when setting a level of consumption which should not be exceeded,
the threshold is typically based on a choice of absolute risk
level which is essentially arbitrary (eg although the threshold
could be set at a 1% risk of premature mortality, it could just
as easily be 2%, 5% or 10%).
1.2.3 In contrast, the relative risk approach
provides a measure of how much greater the risk of drinking at
a particular level is compared to abstinence (eg drinking x
units a day is associated with a y times greater risk
of premature mortality than abstinence). Therefore, it focuses
more clearly on the increase in risk which is actually associated
with consumption. However, relative risk measures do not indicate
whether the risk of higher levels of consumption is large in absolute
terms or just large relative to abstinence.
1.2.4 As noted above, when using absolute risk
measures guidelines for alcohol consumption can be derived by
selecting a threshold level of risk and recommending not drinking
at levels above those associated with that risk. When using relative
risk measures there are two possible ways of deriving guidelines.
Firstly, the threshold can be set at the consumption level above
which the increase in risk of harm, relative to abstinence, becomes
statistically significant. Secondly, and noting the protective
effects of moderate consumption (see below), the threshold can
be set at the consumption level above which the increase in risk
of harm is statistically significantly higher than the greatest
1.3 How up to date is the evidence base?
1.3.1 Studies of the relationship between alcohol
and harm are frequently subjected to systematic reviews in order
to identify those studies of the highest quality and to aggregate
the effects into a more robust overall estimate of the relationship.
Systematic reviews are carried out on a regular basis for individual
and for all-cause mortality.,
This evidence is also compiled in the WHO's work on the burden
of total disease which is due to alcohol.
Therefore, the evidence on which guidelines are based can be considered
as of the highest quality available and is reviewed and updated
on a regular basis.
1.3.2 Recent examples of relative and absolute
risk estimates for different levels of consumption taken from
systematic reviews are provided in figures 1 and 2 below.
RELATIVE RISK FUNCTION FOR TOTAL MORTALITY
BY AVERAGE ALCOHOL CONSUMPTION. SOURCE: DI CASTELNUOVO ET AL.,
ABSOLUTE RISK OF MORTALITY BY AVERAGE ALCOHOL
CONSUMPTION. SOURCE: NHMRC., 2008
2. Could the evidence base and sources of
scientific advice to Government on alcohol be improved?
2.1 We identify several weaknesses in the current
evidence base which should be taken into consideration when formulating
2.2 The type of harm experienced and its link
to different types of drinking
2.2.1 Elevated levels of alcohol consumption
are associated with increased risk of both chronic and
acute health-related harms. Chronic harms are conditions
such as liver cirrhosis, coronary heart disease and cancers and
the risk of having such conditions has been shown to be higher
for individuals with higher levels of average alcohol consumption
over a given time period. Acute harms include injuries and alcohol
poisoning and these harms have been shown to be more closely associated
with higher levels of recent alcohol consumption (ie the level
of intoxication). The evidence base for individual harms is therefore
divided between the risks of harm from an individual's average
alcohol consumption and also their risk from individual episodes
of alcohol consumption.
2.2.2 As drinkers are more likely to be interested
in their risk of mortality from any cause, rather than from a
particular harm, guidelines tend to be based on studies of all
cause mortality. This presents a problem as harms associated with
average and episodic consumption are aggregated. Average consumption
is therefore serving as a less accurate proxy measure of the level
of episodic consumption.
2.2.3 Evidence should recognise that different
types of harm are the results of different types of drinking.
Where possible, evidence should link acute harms to episodic drinking
and chronic harms to average consumption although the limitations
of data do not always permit this. Guidelines should also reflect
this distinction and recommend upper limits for both typical and
episodic consumption. Using the current guidelines as an example,
this would give the recommendation that "men should not regularly
drink more than 3-4 units of alcohol a day and not more than 8
units in any single drinking session".
2.3 The possible protective effects of moderate
2.3.1 Drinking guidelines must take into account
the evidence of a protective effect from moderate alcohol consumption.
This is seen in all cause mortality studies and largely stems
from an apparent reduced risk of coronary heart disease for moderate
drinkers compared to non-drinkers. This protective effect is not
seen at higher levels of alcohol consumption and, importantly,
there is also no protective effect seen in moderate drinkers who
also have regular heavy drinking occasions.
2.3.2 Recent work has questioned the validity
of the protective effect after a review found studies which pooled
"never drinkers" and "former drinkers" into
a single "non-drinker" category saw larger protective
effects than those which separated never and former drinkers.
This suggests a proportion of the mortality risk associated with
abstinence may be due to the inclusion of abstainers who are in
fact former heavy drinkers who now suffer from alcohol-related
coronary heart disease. If ex-drinkers are excluded, a small cardio-protective
effect of moderate consumption remains for older age groups. However,
age-differentiated drinking guidelines would likely make the message
very complex and should probably be avoided.
2.4 The reliability of survey data on consumption
2.4.1 Many studies of the risk of alcohol consumption
are based on survey data which ask respondents to report their
consumption. Such reports are known to substantially underestimate
the amount of alcohol believed to be consumed based on sales data,
by between 40% and 60%. Although efforts have been made to explain
and address this problem,
many estimates of the risk from alcohol consumption may be biased
upwards by under-reporting of heavy consumption.
2.4.2 Further efforts are therefore required
to account for the under-reporting and under-estimation of alcohol
consumption and to minimise the extent of bias on estimates of
the risk from alcohol consumption.
2.5 The influence of factors other than drinking
which are not included in analyses
2.5.1 Most studies make some attempt to take
account of factors other than alcohol consumption which may lead
to harms or premature mortality. For example, studies will typically
account for the fact that men are often at greater risk than women
and that risk of mortality increases with age. However, other
important influences are less consistently taken account of, such
as socioeconomic status, broader health status and a range of
lifestyle factors (eg diet, physical activity and working environment).
As many of these factors are also related to alcohol consumption
(eg those who drink more tend to be less active and have a poorer
diet) failure to account for them may mean their effects on mortality
or harm are incorrectly attributed to alcohol consumption. In
particular, these factors have been identified as potentially
leading to overestimation of the protective effects of alcohol
at moderate levels of consumption.
2.5.2 Again, further work is required to establish
the extent to which estimates of the level of risk due to alcohol
consumption are biased by factors not included in analyses.
2.6 Protection of data
2.6.1 We also note that the NHS Information Centre
recently withdrew its contribution to the funding of the General
Lifestyle Survey (GLS). This has meant no further data will be
collected on alcohol and other health issues. The GLS (and its
predecessor the General Household Survey) provided a valuable
source of in-depth data on alcohol consumption in the UK stretching
back over four decades. They are recognised as the best source
of data on UK consumption in the UK and are the basis for key
government reports on consumption and many academic studies. Failing
to protect such data sources greatly weakens the ability of the
scientific community to advise the Government on alcohol.
2.6.2 The GLS also collected longitudinal data
on the alcohol consumption of a panel comprising of the same individuals
at several time points; however, due to funding shortages, this
data is not being made available to researchers. This is a wasted
opportunity as no other panel study in the UK has collected such
rich data on alcohol consumption and other health-related variables.
Again, failure to fund the release of valuable consumption data
is a major hindrance to the scientific community's efforts to
provide authoritative advice to the Government.
3. How well does the Government communicate
its guidelines and the risks of alcohol to the public?
3.1 The NHS Information Centre reports on data
collected in two surveys examining adults' awareness, recall and
adherence to drinking guidelines.
3.2 The findings show that awareness of units
of alcohol is high with 90% of respondents in 2009 having heard
of units and this has risen from 79% in 1997. Respondents were
slightly less likely to have heard of drinking limits with 75%
having done so, up from 54% in 1997. However, it is concerning
that only 35% of men and 43% of women claimed to know what the
recommendations which applied to them were. Furthermore, the NHS
Information Centre report notes that those respondents who attempted
to state the recommendations were more often wrong than right.
3.3 In addition to being aware of the guidelines,
adherence to guidelines require drinkers to also monitor their
consumption which means being aware of the number of units in
drinks they consume and, as necessary, keeping a check on their
daily or weekly consumption. Although knowledge of the number
of units in preferred drinks was relatively high at around 60%-70%,
just 13% of drinkers kept a check on their consumption in 2009.
This may many individual's belief that their consumption is at
a moderate level, however it also suggests conscious adherence
to drinking guidelines is rare.
3.4 Heavier drinkers were more likely to have
heard of units and drinking limits and frequent drinkers were
also more likely to be able to correctly identify the unit content
of drinks. This suggests information campaigns have been successful
in ensuring those drinkers at the greatest risk are more aware
of that risk. It may also suggest that including the unit content
on labels eventually leads to retention of this information. However,
other information was less successfully communicated as heavy
drinkers were no more likely to recall what the recommended drinking
guidelines were. Heavier drinkers were also only slightly more
likely to monitor their alcohol consumption.
3.5 Overall, these findings suggests the Government
has been increasingly successful in communicating the idea of
drinking guidelines and some of the concepts around it, such as
units and unit content of drinks. Success has also been highest
in the target group of heavier drinkers. However, it can claim
less success in communicating recommended levels of consumption,
knowledge of which was low for all groups.
3.6 The use of information campaigns has led
to greater public awareness of the risks associated with drinking
and how these relate to the consumption of different types and
quantities of alcoholic drinks. However, there is little evidence
this knowledge has impacted on behaviour. Whilst it is important
that information campaigns continue to inform the public about
the risks associated with drinking, information alone may have
limited utility in motivating drinkers to reduce their consumption.
To achieve reductions in consumption, further action may be required
both by making explicit reference to the harms which may be incurred
if drinking guidelines are exceeded and taking additional action
beyond information campaigns.
4. How do the UK Government's guidelines compare
to those provided in other countries?
4.1 The attached document produced by Alcohol
in Moderation entitled "Sensible Drinking Guidelines"
gives recommended drinking guidelines for a selection of developed
As different nations define a unit of alcohol differently or base
guidelines upon the notion of a "standard drink", it
is easier to compare guidelines after converting recommended levels
into pure alcohol consumption in grams. Some nations give guidelines
as average daily thresholds whereas others use average weekly
thresholds. For simplicity here, we only compare those with average
4.2 The UK guidelines recommend not regularly
drinking more than 24-32g of pure alcohol a day if you are a man
and not more than 16-24g if you are a woman. These levels are
similar to those used in many other nations such as Italy (24-36g
and 12-24g), the USA (24g and 14g), France (30g and 20g), Germany
(36g and 24g) and New Zealand (30g and 20g). Some nations do have
slightly higher recommendations, particularly for men, such as
The Netherlands and Spain (both 40g and 24g). Few nations have
significantly lower guidelines and those that do include Denmark
(21g and 14g), Poland (20g and 10g) and Slovenia (20g and 10g).
4.3 The UK drinking guidelines can be considered
as in line with other developed nations and there appears no case
to be made for altering them on the basis of international consensus.
5.1 The Sheffield Addiction Research Group would
like to thank Tim Stockwell of the University of Victoria, Canada
for his assistance in producing this document.
6. Declaration of interests
6.1 The Sheffield Addiction Research Group do
not have any potential conflicts of interest and receive no funding
from the alcohol industry.
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