A startling paper was published by the British Medical Journal BMJ 1999:318:1725-1729 by Hart et al of the University of Glasgow and Bristol.
The researchers followed 5766 men aged 35-65 from 1970-73 onwards,
and concluded that there was no clear evidence of any protective
effect conferred by alcohol for those drinking under 22 units
(8g) of alcohol a week and a negative correlation at consumption
levels above this.
The paper is well researched and cross referenced, but there are
important omissions. The researchers report a strong correlation
between drinking and increased risk of stroke (above 22 units
a week), yet fails to define the type of stroke. Former research
has found a reduced risk of ischaemic stroke amongst moderate
consumers, but an increased risk of haemorrhagic stroke amongst
heavy drinkers.
The study does analyse smoking and employment but the questionnaire
did not question diet and exercise habits amongst the respondents.
Finally the number of respondents claiming to be non-consumers
or occasional drinkers is also questionable high at 30% of the
cohort.
John Juergens, Ph.D and Chairman of the American Wine Alliance for Research and Education (Aware) comments:
"There are a multiple of variables involved in such a study...
in the totality of the research so far, the issue is settled.
For many people moderate alcohol consumption in the context of
a moderate, balanced lifestyle (nutrition, exercise, no disease
contra-indications,etc) may have a net health benefit in terms
of cardiovascular functioning, reduced coronary artery disease,
reduced incidence of stroke, and a reduction in overall mortality.
This has been demonstrated in several very robust and well conducted
longitudinal studies on hundreds of thousands of individuals.
These are our best evidence of the validity of alcohol and health
claims".
In contrast to the above report, a study by Wannamethee et al
published in the American Journal of Public Health Vol 89, No 5 1999 which studied 7,735 men aged between 40 and 59 from 24 British
towns over 17 years has found that regular moderate intake of
all alcoholic drinks is associated with a significantly lower
relative risk of CHD when compared with occasional drinkers. Similarly
further studies by Gronbaek et al, published in Age Ageing 27
739-744 has revealed, following a study of the lifestyles of 16,600
men and women aged over 50 that light (moderate) drinking is associated
with lower all-cause mortality than either abstention or heavy
drinking.