Binge drinking among young adult men may lead to increased blood pressure, according to a new study.
But binge drinking didn't cause a similar rise in blood pressure for young adult women or for teenagers, according to the study. In fact, when young adult women drank lightly or moderately, their risk of high blood pressure was cut in half, the study found.
"This finding parallels studies in older adult men and women," said lead researcher Dr. Sarah Twichell, a clinical fellow in paediatrics at Boston Children's Hospital. In older adult men, she said, the more alcohol they consume, the more their risk of high blood pressure (hypertension) increases.
Alcohol not a direct cause
Although this study found a connection between heavy alcohol consumption and an increased risk of high blood pressure in young adults, the study did not prove alcohol was the direct cause of higher blood pressure.
For a long time, researchers have been aware of a link between heavy alcohol consumption and high blood pressure, said Dr. Guy Mayeda, a cardiologist at Good Samaritan Hospital in Los Angeles, but this study reveals how early it can start.
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"The thought is that in your 20s, you're invincible and immune to all these middle-aged diseases like heart disease and hypertension, but this study shows that young adult males who binge drink have higher instances of blood pressure," Mayeda said.
Binge drinking is defined as having more than five drinks in one sitting for males and more than four in one sitting for females, Twichell said.
Twichell's team analysed information from a 2010 survey of approximately 8,600 participants. The study volunteers were initially recruited in 1996, when the participants were 8 to 14 years old, according to the study. They completed detailed surveys every one to two years for the study. In 2010, the participants were 22 to 28 years old.
The researchers found young adult men were 70 percent more likely to develop high blood pressure if they binge drank frequently in the previous year. The researchers adjusted the data to account for weight, age, race and smoking, according to Twichell.
Meanwhile, young adult women with light or moderate alcohol use were between 45 and 62 percent less likely to have high blood pressure, according to the study.
The reason drinking has variable effects on blood pressure has to do with the way alcohol affects the blood vessels, Mayeda said.
"Usually when you first drink, your blood pressure drops, but when you're binge drinking, when you stop the binge, there's a withdrawal," he said. "For people going through alcohol withdrawal, their heart rate goes up high and their blood pressure goes up high."
Alcohol affects blood vessels
Alcohol is a vasodilator, which means it dilates, or enlarges the blood vessels initially, allowing for greater blood flow, he said.
But during withdrawal, the blood vessels shrink, according to Dr. Sarah Samaan, cardiologist and co-chair of the echocardiography laboratory at Legacy Heart Centre in Plano, Texas.
"Binge drinking may also increase adrenaline levels and raise levels of other hormones and blood chemicals like cortisol, which are associated with high blood pressure," she said. "Since hypertension raises the risk for heart disease, stroke and kidney disease, young men who binge drink put themselves in harm's way in more ways than one."
It's unclear why the effect wasn't seen in teens, but it may have to do with the amount of data available, Twichell said.
"Fewer adolescents reported a very high degree of alcohol consumption, and this difference could have prevented us from being able to find an association," she said. "It is also possible that the effects of binge drinking are different in adolescents and adults, but the rationale for this is not clear."
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Samaan suggested other possibilities related to physical differences among the participants.
"Young women and teen boys typically have lower blood pressure readings, so it's likely that even binge drinking will not cause the blood pressure to rise about the 'normal' threshold," she said. "For women, it's possible that oestrogen has some protective effect on blood pressure, although there is no way to determine that from this study."
Another possibility, said Mayeda, is that the blood vessels are still very flexible in teens, something that has been seen in autopsies of children, he said.
Alcohol toxic to the heart
These findings don't mean that women don't have to be concerned about their alcohol consumption, according to Mayeda, who said that alcohol can have other adverse cardiac effects.
"Alcohol becomes toxic to the heart muscle," he said. "With high alcohol exposure, we always think of patients developing liver failure, but at the extremes, it can cause congestive heart failure."
The researchers are scheduled to present their findings at American Society of Nephrology's Kidney Week 2014, in Philadelphia. Findings presented at meetings are generally considered preliminary until they've been published in a peer-reviewed journal.
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