Alcohol and the Cardiovascular System
There is a largevariability in the response of CHD risk factors to Alcohol use.
Studies have shown a U or J shaped relation between CHD mortality and alcohol use. The protective effect of light-to-moderate drinking may be mediated by elevated HDL and insulin sensitivity, lowered LDL and lipoprotein (a) levels and a beneficial haemostatic balance. However, heavy drinking in part neutralises these effects,by increasing blood pressure and triglycerides.This cross sectional study by Hashimo Y, Futamura A, Nakarai H and Nakahara K, undertook to examine whether there is individual variability in response to alcohol of serum levels of triglycerides, HDL-cholesterol and uric acid as well as blood pressure.
Subjects for the study were 310 Japanese males who underwent an annual health check- up. Criteria for exclusion were a BMI>24, alcohol use >566 ml/week, medication for hypertension,diabetes, hyperlidaemia or hyperuricaemia and incomplete examinations or answers. A questionnaire was used to collect information on current medication, smoking and alcohol use. After a 12 hour fast blood samples were taken first thing in the morning. Subjects were divided into those with normal GGT values (>40 IU/1) and those with elevated GGT values (>40 IU/1). After adjustment for age, BMI, exercise and smoking the two groups were compared.
In the high-GGT group triglycerides levels increased by drinking level but not in the normal -GGT group.In both groups HDL-levels increased with drinking and there was no difference in the groups for mean HDL-levels. In both groups uric acid levels and blood pressure increased with increasing drinking levels ,but the increase were largest in the high-GGT group.
The results indicate that there is large variability in the response of CHD risk factors to alcohol use.The detrimental effects of alcohol may be reduced in subjects whose GGT level responds less to alcohol.
source Hashimo Y, Futamura A, Nakarai H, Nakahara K. Relationship between y-glutamyl transpeptidase to alcohol drinking and risk factors for coronary heart disease. Atherosclerosis 158 (2001) 465-470.
Death After Heart Attack
The conclusion drawn from an investigation in the United Stated was that people who drink in moderation may improve their chances of surviving a heart attack. The investigation showed that both men and women had a 20-30% greater chance of surviving a myocardial infarction, as compared with teetotallers, if they had regularly taken moderate amounts of alcohol in the preceding year.
There is now a wealth of evidence that modest drinking significantly reduces the risk of a person having a heart attack, however, until now no-one has systematically investigated a rather different question: Does prior drinking affect the chances of recovery after such an attack? This was the purpose of the new study by Mukamal K.J., Maclure M., J.E., Sherwood J.B.and Mittleman M.A. which took place in 45 different community and tertiary care medical centres.
Within an average of 4 days after a myocardial infarction, skilled interviewers spoke to nearly 2000 patients, one third of them were women. A total of 1913 individuals data was analysed after excluding those who did not provide information about their drinking habits, plus those with a history of alcoholism who were now abstaining.
The crucial information gathered during the interviews was about the average quantities which subjects had consumed over the past year, subdivided into wine, beer and spirits. With adjustment for the difference quantities of alcohol in each type of beverage, the investigators categorised the individuals according to whether they had taken more than about 13UK (8g) units per week, less than this amount or none at all.
Patients were followed up for an average of 4 years, during which time all deaths were recorded. The numbers of fatalities were then correlated with the 3 levels of alcohol consumption along with other data collected during the interviews.
The outcome of the study was that individuals who had taken up to 13 units of alcohol per week in the year prior to their heart attack were 20% more likely to survive the experience and those who had consumed 13 units or more per week were even less likely to die. The benefit was apparent in both men and women, and in those who took predominantly beer, wine and spirits. The reduction in the risk of dying did not apply to coronary deaths but to total mortality over the period studied.
One deficiency of the US study was that it was not able to throw light on the consequences of relatively heavy drinking. Of the 1913 subjects involved, only 107 reported consumption of 40 units or more per week, of whom only 8 died, therefore these figures were to small to permit any reliable generalisation concerning the significance of this level of intake.
Various factors which might have influenced the results and thus led to misleading conclusions were also addressed by the US team. For example, consumers of alcohol may be more likely to engage in physical activity, and to have higher socio-economic status, than abstainers. However, the figures cited above were already adjusted to allow for these influences: the reductions in mortality were greater without adjustments of this sort.
The authors therefore believe that their findings are "robust". Taken together with the results of previous work, they indicate that moderate drinking is associated with both a lower likelihood of acute myocardial infarction and a reduced risk of mortality in the years following such an attack.
source Prior Alcohol Consumption and Mortality Following Acute Myocardial infarction, Journal of the American Medical Association (2001), 285, 1965-70, Mukamal K.J., Maclure M., J.E., Sherwood J.B., Mittleman M.A., Divisions of General Medicine, Primary Care and Cardiology; Beth Israel Deaconess Medical Centre; and Departments of Epidemiology and Health and Social Behaviour, Harvard School of Public Health and Division of Cardiology, Massachusetts General Hospital, Boston, M.A. USA.