We’ve all seen the reports suggesting that wine consumption, particular red wine, is beneficial for many aspects of one’s health, with the most studied probably being wine’s affect on cardiovascular health. Studies have shown that red wine consumption may have cardiovascular health benefits by way of cardioprotective properties. Of course, there are other studies that suggest there is no link between red wine consumption and cardiovascular health benefits; however, when in consumed in moderation, there does appear to be something going on.
Most of the studies to date have examined animals or people with or without cardiac disease risk factors prior to any adverse events occurring. According tothe authors of the short study presented today, very few studies have examined the effect of red wine consumption on people who have recently experienced a cardiac event and how their risk changes with continued red wine consumption post cardiac event.
A total of 11,323 Italian participants were enrolled in this study. Questions regarding demographics, cardiovascular risk factors, medications, dietary habits, and medical history were answered. After cardiac events, participants were given advice and instructions on how they should eat and/or drink and general lifestyle changes.
Participants were followed over time at clinic visits to update information on any lifestyle and health changes. Clinic visits were 0.5, 1.5, and 3.5 years after the initial cardiac event. Heart attack was considered the initial cardiac event.
Daily wine intake was determined and consumers were separated into the following categories: 1) never/almost never; 2) up to 0.5L per day (0.1-3.3 glasses); 3) between 0.5L and 1L per day (3.4-6.8 glasses); and 4) greater than 1L per day (greater than 6.8 glasses).
- 85.4% of participants were male and 14.6% were female.
- After heart attack, those participants drinking higher amounts of wine tended to be younger, more likely have lower systolic blood pressure, able to perform an exercise stress test, current smoker and less likely to have had more than one heart attack, diabetes, or hypertension.
- Wine consumption as associated with consumption of butter, cheese, coffee, and oils and negatively associated with consumption of fish, fruit, vegetables, and olive oil.
- During the first 6 months after heart attack, the proportion on non-drinkers increased.
- 21.6% of wine drinkers reported giving up drinking after heart attack.
- 24% of those drinking less than 0.5L and 15% of those drinking greater than 0.5L stopped drinking wine completely.
- For those drinking greater than 0.5L of wine per day, 80% of them reduced their wine consumption by 6 months after heart attack.
- Only a small number of participants increased wine consumption after heart attack.
- After 37,021 person-years after the initial heart attack, there were 1168 cardiovascular events including 671 deaths related to cardiovascular events, 456 heart attacks (nonfatal), and 119 strokes (nonfatal).
- NOTE: To understand the concept of the person-year, please visit this website: https://www.ctspedia.org/do/view/CTSpedia/StudyIncidencePersonTime#Person_Time_Incidence_Rates
- The rate of new cardiovascular events was lower in participants who consumed higher levels of wine.
- The rate of new cardiovascular events was lowest in participants who consumed moderate levels of wine (up to 0.5L per day).
- The risk of new cardiovascular events decreased by 13% for those consuming up to 0.5L of wine per day compared with nondrinkers.
- No significant differences between wine consumption and cardiovascular events were found when other confounding factors were included (i.e. sex and compliance with advised treatment).
- Pharmacological treatments did not affect the results of the study.
- After the long-term follow up (between 5.7 and 7.3 years) and 60,022 person-years, 1659 participants had died (1400 men and 259 women).
- Wine consumption up to 0.5L and more than 0.5L per day was associated with a lower risk of death than nondrinkers.
According to the authors, the results of this study suggest that moderate wine consumption was associated with a new cardiovascular event after a prior heart attack. However, once changing in drinking habits and other confounding factors were taken into consideration, this association was no longer significant. The authors noted that since they were not able to include the highest level of alcohol consumption (greater than 1L per day) due to too few participants actually consuming that much on a regular basis, there could have been some weakening in power of the analysis.
If you don’t take the confounding factors into consideration, the results suggest that there is a negative association between moderate wine consumption andcardiovascular events and death due to new cardiovascular events. According to the authors, those Italian individuals with prior cardiovascular history may have reduced risk of repeat events if they consume moderate amounts of wine.
Taking confounding factors into consideration is very important, so I’m not sure why the authors would still focus on the positive results they found prior to taking these results into consideration. The fact of the matter is that confounding factors are important, and if including them in the model result in insignificant results, well then that should be the result you present. There were other factors that were not taken into consideration that limited the study, including data on physical activity and other types of alcohol consumed by participants. Both of these could have significant impacts on the results of the study.
The authors concluded by saying that light to moderate wine consumption was not associated with increased risks of cardiovascular events or cardiovascular-related deaths, which is a result I can get on board with based on the statistics. While it is true wine consumption did not increase the risk of further cardiovascular events, it is not clear whether or not wine consumption actually decreases this risk. The study should be repeated with more confounding factors taken into consideration. Also, the study should be repeated in other locations, since the dietary habits of Italians and people from other corners of the world are different and thereby the cardiovascular risks will likely be different.
I’d love to hear what you all think of this study. Please feel free to leave your comments!
Source: Levantesi, G., Marfisi, R., Mozaffarian, D., Franzosi, M.G., Maggioni, A., Nicolosi, G.L., Schweiger, C., Siletta, M., Tavazzi, L., Tognoni, G., and Marchioli, R. 2011. Wine consumption and risk of cardiovascular events after myocardial infarction: Results from the GISSI-Prevenzione trial. International Journal of Cardiology, doi: 10.1016/j.ijcard.2011.06.053.