Heavy drinkers more often end up in the hospital with pneumonia, suggests a new study from Denmark.
But it was only men who said they had more than 50 drinks a week who were at higher risk.
The study isn't the first to find a link between alcohol and pneumonia. Yet researchers can't be sure that drinking by itself leads to pneumonia, it could be that alcohol-linked chronic diseases like liver and heart problems may play a role, for example.
In the current report, Dr Reimar Wernich Thomsen of Aarhus University Hospital and colleagues used data from a large Danish health study, including more than 45,000 people age 50 to 64, who had never had pneumonia.
All participants filled out surveys at the beginning of the study, which included questions on how often they drank beer, wine, and hard liquor. Overall, the average was six drinks per week for women and 12 per week for men.
Over the next 12 years, about 4% of participants had a pneumonia-related hospitalisation.
Risks, men vs. women
Regardless of how much they said they drank, from nothing to more than 35 drinks each week, women had a similar risk of pneumonia, the researchers reported in the European Respiratory Journal.
However, men who drank more than 50 drinks each week were about 80% more likely to be hospitalised with pneumonia compared to those who had between one and six drinks each week, after adjustment for factors like smoking and weight.
About one in thirty men drank enough to land himself in that category.
After adjustment for comorbidities, the link between alcohol and pneumonia in men remained but was weaker.
"The general idea is that alcohol impairs the immune system -- every single part of the immune system," said Dr Andriy Samokhvalov, of Toronto's Centre for Addiction and Mental Health, who was not involved in the new study.
If excessive drinking really does lead to pneumonia, exactly how much a person would need to drink to be at increased risk remains uncertain. And it doesn't help that the study relied on self-reports of drinking habits, which could weaken the results.
Dr Samokhvalov said, "We think there must be a threshold around four drinks per day."
Both men and women had a higher pneumonia risk if they did their drinking infrequently in high doses, rather than spaced out over the week.
The researchers agreed it makes sense that people who binge drink and black out on the sidewalk would be hampering their immune system.
Dr. Marjolein de Wit, who studies alcohol and critical illness at Virginia Commonwealth University in Richmond, said that frequent drinkers also have a higher risk for nosocomial pneumonia when they're admitted for other reasons. And when they do get infected, their risk of dying is higher.
(Reuters Health, Genevra Pittman, June 2011)