Cholesterol is a type of fat. Your body needs it for many things, such as making new cells. But too much cholesterol in your blood increases your chances of having a heart attack and stroke.
You get cholesterol from the foods you eat and from your liver. Your liver makes most of the cholesterol your body needs.
Desirable cholesterol is less than 200 milligrams per deciliter (mg/dL).
Borderline-high cholesterol is 200 to 239.
High cholesterol is 240 or higher.
What are the different kinds of cholesterol?
Cholesterol travels through your blood attached to a protein. This cholesterol-protein package is called a lipoprotein. Lipoproteins are either high-density or low-density, based on how much protein and fat they have.
Low-density lipoproteins (LDL) are mostly fat with only a small amount of protein. LDL is the bad kind of cholesterol because it can clog your arteries. If you have high cholesterol, your doctor will want you to lower your LDL.
LDL levels:
Best LDL is less than 100 mg/dL.
Near best LDL is 100 to 129.
Borderline-high LDL is 130 to 159.
High LDL is 160 to 189.
Very high LDL is 190 and above.
See an illustration of a clogged artery (atherosclerosis).
High-density lipoproteins (HDL) help clear the bad cholesterol from your blood and keep it from clogging your arteries. HDL is the good kind of cholesterol. High levels of HDL (60 or above) can protect you from a heart attack.
HDL levels:
Desirable or high HDL is 60 mg/dL or above.
Undesirable or low HDL is less than 40.
Triglycerides are another type of fat in your blood. If you have high triglycerides and high LDL, your chances of having a heart attack are higher.
Triglyceride levels:
Borderline high is 150 to 199 mg/dL.
High is 200 or above.
Very high is 500 or higher.
What causes high cholesterol?
High cholesterol may run in your family. The foods you eat also may cause high cholesterol.
Causes include:
Your diet. Eating too much saturated fat and cholesterol can cause high cholesterol. Saturated fat and cholesterol come from animal foods such as beef, pork, veal, milk, eggs, butter, and cheese. Many packaged foods contain saturated fat such as coconut oil, palm oil, or cocoa butter. You will also find saturated fat in stick margarine and vegetable shortening. Cookies, crackers, chips, and other snacks usually contain partially hydrogenated vegetable oil or trans fat, which can raise cholesterol.
Your weight. Being overweight may raise triglycerides and lower HDL.
Your activity level. Not exercising may raise LDL and lower HDL.
Your overall health. Having diseases such as low thyroid can raise cholesterol. Cigarette smoking may lower HDL.
Your age. After you reach age 20, your cholesterol starts to rise. In men, cholesterol levels usually level off after age 50. In women, cholesterol levels stay fairly low until menopause. After that, they rise to about the same level as in men.
Your family. A disease called a lipid disorder can also cause high cholesterol. This rare problem is inherited from family members, and it changes how your body handles cholesterol. If you have a lipid disorder, your cholesterol may be well over 250 mg/dL. It may be harder to treat.
What are the symptoms?
High cholesterol doesn't make you feel sick. But if cholesterol builds up in your arteries, it can block blood flow to your heart or brain and cause a heart attack or stroke.
In some people, cholesterol deposits called xanthomas may form under the skin. They look like small bumps.
How is high cholesterol diagnosed?
Your doctor will use a blood test to check your cholesterol.
A lipoprotein analysis is the most complete test. It measures your total cholesterol: HDL, LDL, and triglycerides. You cannot have food for 12 hours before this test.
A simple cholesterol test can measure your total cholesterol and HDL. You can eat before this test. Sometimes doctors do this test first and then order a lipoprotein analysis if you have high cholesterol or low HDL.
How is it treated?
You and your doctor may decide first to treat your high cholesterol without medicine. Changes to your lifestyle and diet may be all you need. These changes include eating foods low in saturated fat, being more active, losing weight if you need to, and quitting smoking if needed.
If you cannot lower your cholesterol enough after trying lifestyle changes for a few months, you may need to take a medicine called a statin.
If you have high blood pressure, diabetes, or coronary artery disease (CAD), your doctor may want you to take a statin right away. This is because your chance of having a heart attack is higher.
Use this Interactive Tool: Are You at Risk for a Heart Attack?
Research shows that people who have a high risk for heart attack could benefit from taking higher doses of statins to lower their LDL cholesterol as much as possible. The more these people can lower their LDL, the less likely they are to have a heart attack. 1
Things that increase your risk for heart attack include:
Having high blood pressure.
Smoking.
Having low HDL (good) cholesterol.
Having peripheral arterial disease, which is narrowing of the arteries that supply blood to the legs, abdomen, pelvis, arms, or neck.
Having diabetes.
Having a family history of heart disease.
Being age 45 or older if you are a man, and age 55 or older if you are a woman.
Monday, May 28, 2007
Four more breast cancer genes found
Monday, 28 May 2007. www.abc.net.au
Four more genes that play a role in breast cancer have been uncovered by an international team of scientists.But women who have mutated versions of these genes have a relatively low risk of developing breast cancer, which scientists say makes it unlikely that individual screening tests for these mutations will be developed.
Researchers, including those from Australia, publish their results today in the journals Nature and Nature Genetics.Genetic causes account for between 5-10% of breast cancer cases, with lifestyle factors such as smoking and environmental factors accounting for the rest.But until now, only about 25% of the genes that are suspected to cause inherited breast cancer have been identified. The new culprits - flawed versions of genes called FGFR2, TNRC9, MAP3K1 and LSP1 - are believed to account for an additional 4%. The researchers found them after sifting through the DNA of nearly 50,000 women, half of them healthy and half of them patients with breast cancer. While flawed versions of the four genes are common in the general population, the good news is that the genes are considered a relatively low hazard.This means that women who have them run a comparatively small risk of developing cancer.
By contrast, the breast cancer genes BRCA1 and BRCA2 are relatively rare in the population but women who have them run a high risk of the disease. Because the four newly-identified genes are so common yet relatively low-risk, individual tests for them may be unsuitable, according to Cancer Research UK, whose scientists led the investigation."[But] as more of these 'low-risk' genes are found it may be possible to design tests for a combination of genes," it says."This could help doctors make decisions about prevention, diagnosis and treatment for women who inherit faults in one or more of these genes."
There could be as many as 200 genes that influence someone's chance of developing breast cancer (Image: iStockphoto)Dr Georgia Chevenix-Trench, from the Queensland Institute of Medical Research, contributed data from Australian patients to the study."This is probably the most important paper on breast cancer genetics since the cloning of BRCA2 in 1995," she says.She adds that there are probably 100-200 similar genes that contribute to breast cancer risk and that these studies will give researchers a good idea of where to look for them.Much remains to be learnt about the four genes, especially whether they react with each other or with lifestyle factors in a way that boosts the risk for some women, the scientists add.Most previously identified breast cancer genes are involved in DNA repair. But these latest genes seem to be more related to the control of cell growth or to cell signalling.
Of the four genes identified, only FGFR2 was known to be associated with breast cancer.And scientists say it may be a logical candidate for a breast cancer gene. It encodes a receptor, a kind of molecular doorway, for a compound called tyrosine kinase that is involved in several cancers.One of the studies found there were four common mutations in the gene that were associated with sporadic breast cancer in postmenopausal women, women who developed cancer without known risk factors for it.
The mutations raised the risk of breast cancer risk by 20% if a woman carried one copy of the gene and by 60% if she carried two copies. And close to 60% of the women studied carried at least one copy.But the findings do not yet have any real relevance for women, says author Professor David Hunter of Harvard University."It is premature to recommend screening women for these gene variants, at least until the scientific community has further combed through the genome-wide findings and found all the variants that are associated with increased risk," he says.More evidence for TNRC9 In the third study, researchers found genetic variants on chromosomes 2 and 16, both increasing the risk of oestrogen receptor-positive breast cancer.One of these variants is near to the gene TNRC9, one of the genes found in another of the other studies released today.
Four more genes that play a role in breast cancer have been uncovered by an international team of scientists.But women who have mutated versions of these genes have a relatively low risk of developing breast cancer, which scientists say makes it unlikely that individual screening tests for these mutations will be developed.
Researchers, including those from Australia, publish their results today in the journals Nature and Nature Genetics.Genetic causes account for between 5-10% of breast cancer cases, with lifestyle factors such as smoking and environmental factors accounting for the rest.But until now, only about 25% of the genes that are suspected to cause inherited breast cancer have been identified. The new culprits - flawed versions of genes called FGFR2, TNRC9, MAP3K1 and LSP1 - are believed to account for an additional 4%. The researchers found them after sifting through the DNA of nearly 50,000 women, half of them healthy and half of them patients with breast cancer. While flawed versions of the four genes are common in the general population, the good news is that the genes are considered a relatively low hazard.This means that women who have them run a comparatively small risk of developing cancer.
By contrast, the breast cancer genes BRCA1 and BRCA2 are relatively rare in the population but women who have them run a high risk of the disease. Because the four newly-identified genes are so common yet relatively low-risk, individual tests for them may be unsuitable, according to Cancer Research UK, whose scientists led the investigation."[But] as more of these 'low-risk' genes are found it may be possible to design tests for a combination of genes," it says."This could help doctors make decisions about prevention, diagnosis and treatment for women who inherit faults in one or more of these genes."
There could be as many as 200 genes that influence someone's chance of developing breast cancer (Image: iStockphoto)Dr Georgia Chevenix-Trench, from the Queensland Institute of Medical Research, contributed data from Australian patients to the study."This is probably the most important paper on breast cancer genetics since the cloning of BRCA2 in 1995," she says.She adds that there are probably 100-200 similar genes that contribute to breast cancer risk and that these studies will give researchers a good idea of where to look for them.Much remains to be learnt about the four genes, especially whether they react with each other or with lifestyle factors in a way that boosts the risk for some women, the scientists add.Most previously identified breast cancer genes are involved in DNA repair. But these latest genes seem to be more related to the control of cell growth or to cell signalling.
Of the four genes identified, only FGFR2 was known to be associated with breast cancer.And scientists say it may be a logical candidate for a breast cancer gene. It encodes a receptor, a kind of molecular doorway, for a compound called tyrosine kinase that is involved in several cancers.One of the studies found there were four common mutations in the gene that were associated with sporadic breast cancer in postmenopausal women, women who developed cancer without known risk factors for it.
The mutations raised the risk of breast cancer risk by 20% if a woman carried one copy of the gene and by 60% if she carried two copies. And close to 60% of the women studied carried at least one copy.But the findings do not yet have any real relevance for women, says author Professor David Hunter of Harvard University."It is premature to recommend screening women for these gene variants, at least until the scientific community has further combed through the genome-wide findings and found all the variants that are associated with increased risk," he says.More evidence for TNRC9 In the third study, researchers found genetic variants on chromosomes 2 and 16, both increasing the risk of oestrogen receptor-positive breast cancer.One of these variants is near to the gene TNRC9, one of the genes found in another of the other studies released today.
Wednesday, May 23, 2007
What causes high Cholestrol ?
Cause
High cholesterol may run in your family. The foods you eat may also cause high cholesterol.
Causes include:
What you eat. Eating too much saturated fat can cause high cholesterol. You will find this
unhealthy fat in foods that come from animals. Beef, pork, veal, milk, eggs, butter, and cheese contain saturated fat. Packaged foods that contain coconut oil, palm oil, or cocoa butter may have a lot of saturated fat. You will also find saturated fat in stick margarine, vegetable shortening, and most cookies, crackers, chips, and other snacks.
Your weight. Being overweight may increase triglycerides and decrease HDL.
Your activity level. Lack of physical activity, which may increase LDL and decrease HDL.
Your age and gender. After you reach age 20, your cholesterol levels naturally begin to rise. In men, cholesterol levels generally level off after age 50. In women, cholesterol levels stay fairly low until menopause, after which they rise to about the same level as in men.
Your overall health. Having certain diseases, such as diabetes or hypothyroidism, may cause high cholesterol.
Your family history. If family members have high cholesterol, you may also.
Cigarette smoking. Smoking can lower your good cholesterol.
In rare cases, high cholesterol is caused by an inherited problem called a lipid disorder that changes the way the body handles cholesterol. People with lipid disorders may have total cholesterol levels well over 250 milligrams per deciliter. Certain types of inherited lipid disorders may be more difficult to treat
High cholesterol may run in your family. The foods you eat may also cause high cholesterol.
Causes include:
What you eat. Eating too much saturated fat can cause high cholesterol. You will find this
unhealthy fat in foods that come from animals. Beef, pork, veal, milk, eggs, butter, and cheese contain saturated fat. Packaged foods that contain coconut oil, palm oil, or cocoa butter may have a lot of saturated fat. You will also find saturated fat in stick margarine, vegetable shortening, and most cookies, crackers, chips, and other snacks.
Your weight. Being overweight may increase triglycerides and decrease HDL.
Your activity level. Lack of physical activity, which may increase LDL and decrease HDL.
Your age and gender. After you reach age 20, your cholesterol levels naturally begin to rise. In men, cholesterol levels generally level off after age 50. In women, cholesterol levels stay fairly low until menopause, after which they rise to about the same level as in men.
Your overall health. Having certain diseases, such as diabetes or hypothyroidism, may cause high cholesterol.
Your family history. If family members have high cholesterol, you may also.
Cigarette smoking. Smoking can lower your good cholesterol.
In rare cases, high cholesterol is caused by an inherited problem called a lipid disorder that changes the way the body handles cholesterol. People with lipid disorders may have total cholesterol levels well over 250 milligrams per deciliter. Certain types of inherited lipid disorders may be more difficult to treat
Sunday, May 20, 2007
Mental Development Similar Among Boys, Girls
FRIDAY, May 18 (HealthDay News) -- U.S. scientists are getting the first comprehensive look at how children's brains and behaviors change over time, and it's yielding some surprises.
It turns out that much-touted differences in the mental evolution of boys and girls aren't so pronounced after all.
On the other hand, the amount of money a child's family makes may have a big impact on his or her intellectual ability, with IQs rising alongside incomes.
Those are just the highlights of preliminary findings from a team of psychologists and psychiatrists at the U.S. National Institutes of Health. Their project, the National Institutes of Health MRI Study of Normal Brain Health, is assessing the neurological and behavioral development of 450 American children carefully selected to be free of problems and representing the diversity of the country's population.
"This is being done to learn more about the structural and functional development of the normal brain," explained Deborah P. Waber, associate professor of psychology at Children's Hospital Boston, lead author of the report. "The data will be used as baseline for all kinds of disorders of childhood brain development."
The first findings from the project were published Friday in the online edition of the Journal of the International Neuropsychological Society.
They include:
Mental performance differs little by gender. "We found a few significant differences that we would have suspected," Waber said. "For example, boys are better at visual and spatial tasks, and girls are better at motor speed, but there are no differences in many other paths, like memory."
Family income matters. Kids from more affluent homes do better than those from lower-income families, with average IQs of 105, 110 and 115, respectively, for children classified as low-, middle- and high-income. "But when we limit the groups to healthy children, the differences are not as great," Waber said. "That suggests that the difference has more to do with disparity in health care related to income."
Young children make the biggest gains. Mental performance climbed steadily from age 6, leveled off for most tests between age 10 and 12, and then improved only very slightly or not at all during adolescence, challenging the idea of a growth spurt in learning during the early teens.
In addition to undergoing three rounds of performance and behavioral tests as they aged, the children also underwent MRI and other scans of their brains to study the growth of different brain structures and the formation of neural connections. The scans also tracked changes in brain chemistry. Those images, and the information gleaned from them, will be made available to clinicians and scientists who study brain development.
There will be further reports, but "I don't think we are going to follow these children any further," Waber said. "This has been a very labor-intensive study at six sites across the country. It represents pretty much the limit of what our resources allow us to do."
No comparable study of normal cognitive development has ever been done, noted Judy Rumsey, the project officer who spearheaded the U.S. National Institute of Mental Health's participation in the project.
"This information will help determine what the developmental trajectories are and whether gender differences appear or disappear in the development of typically developing children up to 18 years of age -- children with no neurological disease, developmental disorder or psychiatric disorder," Rumsey said. "There has been nothing as comprehensive as this. It goes down to a very young age, with a sampling designed to insure diversity and representation for different social groups."
It is not possible to say just when the full range of images and information will be made available to professionals, Rumsey said. She said there still are some major issues to be settled, notably that of preserving the privacy of the young people who took part in the project.
More information
The project is described in detail by the U.S. National Institutes of Health.
It turns out that much-touted differences in the mental evolution of boys and girls aren't so pronounced after all.
On the other hand, the amount of money a child's family makes may have a big impact on his or her intellectual ability, with IQs rising alongside incomes.
Those are just the highlights of preliminary findings from a team of psychologists and psychiatrists at the U.S. National Institutes of Health. Their project, the National Institutes of Health MRI Study of Normal Brain Health, is assessing the neurological and behavioral development of 450 American children carefully selected to be free of problems and representing the diversity of the country's population.
"This is being done to learn more about the structural and functional development of the normal brain," explained Deborah P. Waber, associate professor of psychology at Children's Hospital Boston, lead author of the report. "The data will be used as baseline for all kinds of disorders of childhood brain development."
The first findings from the project were published Friday in the online edition of the Journal of the International Neuropsychological Society.
They include:
Mental performance differs little by gender. "We found a few significant differences that we would have suspected," Waber said. "For example, boys are better at visual and spatial tasks, and girls are better at motor speed, but there are no differences in many other paths, like memory."
Family income matters. Kids from more affluent homes do better than those from lower-income families, with average IQs of 105, 110 and 115, respectively, for children classified as low-, middle- and high-income. "But when we limit the groups to healthy children, the differences are not as great," Waber said. "That suggests that the difference has more to do with disparity in health care related to income."
Young children make the biggest gains. Mental performance climbed steadily from age 6, leveled off for most tests between age 10 and 12, and then improved only very slightly or not at all during adolescence, challenging the idea of a growth spurt in learning during the early teens.
In addition to undergoing three rounds of performance and behavioral tests as they aged, the children also underwent MRI and other scans of their brains to study the growth of different brain structures and the formation of neural connections. The scans also tracked changes in brain chemistry. Those images, and the information gleaned from them, will be made available to clinicians and scientists who study brain development.
There will be further reports, but "I don't think we are going to follow these children any further," Waber said. "This has been a very labor-intensive study at six sites across the country. It represents pretty much the limit of what our resources allow us to do."
No comparable study of normal cognitive development has ever been done, noted Judy Rumsey, the project officer who spearheaded the U.S. National Institute of Mental Health's participation in the project.
"This information will help determine what the developmental trajectories are and whether gender differences appear or disappear in the development of typically developing children up to 18 years of age -- children with no neurological disease, developmental disorder or psychiatric disorder," Rumsey said. "There has been nothing as comprehensive as this. It goes down to a very young age, with a sampling designed to insure diversity and representation for different social groups."
It is not possible to say just when the full range of images and information will be made available to professionals, Rumsey said. She said there still are some major issues to be settled, notably that of preserving the privacy of the young people who took part in the project.
More information
The project is described in detail by the U.S. National Institutes of Health.
Wednesday, May 16, 2007
Heat Waves and Breathing problems
Posted by Franklin Adkinson, M.D. on Thu, May 10, 2007, 8:19 am PDT
You may remember last summer's sweltering heat wave and the many tragic heat-related deaths. As we approach the warmer months this year, it's important to remember how asthma can be triggered by protracted heat.
It's not so much the heat itself that aggravates asthma but the air inversions that result from heat waves. These inversions, in which a layer of warm air is trapped by cooler air above, can increase the amount of toxic air pollutants by more than tenfold.
The increase in harmful oxidants and particles present during heat waves makes breathing even harder for persons with asthma and other chronic respiratory conditions.
These breathing difficulties are not caused by the extra allergens in the air but because they increase the twitchiness of the airways, making the lungs more vulnerable to the allergens we are always exposed to, like Grandma's cat, dust mites, or molds.
If you have asthma and are caught in a heat wave and your start to wonder when it's all going to end, stay in air-conditioned comfort as much as possible and get your exercise in the swimming pool or at an air-conditioned gym. Your local weather channel's air-pollution alert can give you daily updates about the quality of the air you can expect in your region.
Hot weather deserves healthy respect, especially from people with heart and lung diseases. Stay ahead of the game by drinking lots of fluids.
You may remember last summer's sweltering heat wave and the many tragic heat-related deaths. As we approach the warmer months this year, it's important to remember how asthma can be triggered by protracted heat.
It's not so much the heat itself that aggravates asthma but the air inversions that result from heat waves. These inversions, in which a layer of warm air is trapped by cooler air above, can increase the amount of toxic air pollutants by more than tenfold.
The increase in harmful oxidants and particles present during heat waves makes breathing even harder for persons with asthma and other chronic respiratory conditions.
These breathing difficulties are not caused by the extra allergens in the air but because they increase the twitchiness of the airways, making the lungs more vulnerable to the allergens we are always exposed to, like Grandma's cat, dust mites, or molds.
If you have asthma and are caught in a heat wave and your start to wonder when it's all going to end, stay in air-conditioned comfort as much as possible and get your exercise in the swimming pool or at an air-conditioned gym. Your local weather channel's air-pollution alert can give you daily updates about the quality of the air you can expect in your region.
Hot weather deserves healthy respect, especially from people with heart and lung diseases. Stay ahead of the game by drinking lots of fluids.
Saturday, May 12, 2007
Heavy Drinking May Trigger Irregular Heart Rhythm
May 10, 2007 08:40:43 PM PST By Amanda GardnerHealthDay Reporter
THURSDAY, May 10 (HealthDay News) -- Raising a glass too often could put heavy drinkers at risk for atrial fibrillation, a dangerous heart condition that can trip off a stroke or heart failure, British researchers warn.
Luckily, reducing alcohol consumption even a little bit makes a big difference, said the authors of a study slated for presentation Thursday at the annual meeting of the Heart Rhythm Society, in Denver.
"We can't extrapolate from this study that heavy drinking is responsible, but it certainly is an interesting finding," added Dr. Rudolph Nisi, chief of cardiology at Westchester Square Medical Center in New York City. He was not involved in the study.
The finding also underscores the importance of responsible drinking.
"Drinking in moderation . . . is safe and does not significantly increase the chances of developing new atrial fibrillation (AF)," said Dr. Joe Martins, lead author of the study and a cardiologist at the Imperial College, London. "However, drinking in excess of this was strongly associated with an increased probability of developing new AF."
Atrial fibrillation is the most common irregular heart rhythm. A recent study indicates that the problem may be even more common than previously thought. That study, appearing in the journal Circulation, estimated that 5.1 million Americans have atrial fibrillation, not 2.2 million as originally thought.
"AF is becoming an increasing public health burden," Martins said. "It is associated with a fivefold increased risk of stroke, a three-fold risk of heart failure and up to a two-fold increase risk of death."Drinking has been associated with cardiac disease in the past, including rhythm disturbances, experts said.
There is a higher incidence of arrhythmias around the holidays, thus giving rise to so-called "Holiday Heart Syndrome," noted Dr. John P. Erwin III, assistant professor of internal medicine at Texas A&M Health Science Center College of Medicine and a cardiologist with Scott & White Hospital. "Around the holidays, when people are imbibing more than they're accustomed to, there are more people coming in with new onset atrial fibrillation," Erwin said. "So there's been a somewhat loose correlation with alcohol consumption and atrial fibrillation."
And, according to the study authors, binge drinking has also been associated with atrial fibrillation in the past, even though data on long-term alcohol consumption and risk is less clear.
For this study, all patients arriving at an arrhythmia clinic at Charing Cross Hospital in London with symptoms of a new cardiac arrhythmia were asked about their weekly alcohol consumption.
Participants were grouped according to how much they drank: teetotaler (those who abstained completely), moderate drinkers (1-14 units per week for females and one to 21 units per week for males) and excessive (anything greater than moderate). In the study, two units were about equal to one pint of beer.
Those with confirmed atrial fibrillation were then compared to those without the irregular heart beat. About half (48 percent) of people in each group were moderate drinkers, suggesting no increase in risk. Excessive drinking, however, was much higher in patients with atrial fibrillation than in patients without (27 percent versus 17 percent, respectively).
In fact, these heavy drinkers raised their risk of atrial fibrillation by 2 percent for each additional unit they drank compared to non-drinkers.
It's not clear how alcohol and rhythm disturbances might be linked, but the experts offered up some theories.
One is that heavy drinking ramps up the body's "fight-or-flight" response, Erwin said. Another is that drinking can raise the level of fatty acids in the bloodstream.
"Several mechanisms have been suggested from very small studies, including the high adrenaline state of drinking and alcohol withdrawal and impaired vagal heart rate control," Martins said.
Cutting down on drinking could lower the risk, he said.
"We found that nearly one in five of all 984 patients that we evaluated in our study admitted to drinking more than the recommended level," Martins said. "If this behavior could be modified, one might speculate that it could potentially result in a significant reduction in the number of new AF cases."
THURSDAY, May 10 (HealthDay News) -- Raising a glass too often could put heavy drinkers at risk for atrial fibrillation, a dangerous heart condition that can trip off a stroke or heart failure, British researchers warn.
Luckily, reducing alcohol consumption even a little bit makes a big difference, said the authors of a study slated for presentation Thursday at the annual meeting of the Heart Rhythm Society, in Denver.
"We can't extrapolate from this study that heavy drinking is responsible, but it certainly is an interesting finding," added Dr. Rudolph Nisi, chief of cardiology at Westchester Square Medical Center in New York City. He was not involved in the study.
The finding also underscores the importance of responsible drinking.
"Drinking in moderation . . . is safe and does not significantly increase the chances of developing new atrial fibrillation (AF)," said Dr. Joe Martins, lead author of the study and a cardiologist at the Imperial College, London. "However, drinking in excess of this was strongly associated with an increased probability of developing new AF."
Atrial fibrillation is the most common irregular heart rhythm. A recent study indicates that the problem may be even more common than previously thought. That study, appearing in the journal Circulation, estimated that 5.1 million Americans have atrial fibrillation, not 2.2 million as originally thought.
"AF is becoming an increasing public health burden," Martins said. "It is associated with a fivefold increased risk of stroke, a three-fold risk of heart failure and up to a two-fold increase risk of death."Drinking has been associated with cardiac disease in the past, including rhythm disturbances, experts said.
There is a higher incidence of arrhythmias around the holidays, thus giving rise to so-called "Holiday Heart Syndrome," noted Dr. John P. Erwin III, assistant professor of internal medicine at Texas A&M Health Science Center College of Medicine and a cardiologist with Scott & White Hospital. "Around the holidays, when people are imbibing more than they're accustomed to, there are more people coming in with new onset atrial fibrillation," Erwin said. "So there's been a somewhat loose correlation with alcohol consumption and atrial fibrillation."
And, according to the study authors, binge drinking has also been associated with atrial fibrillation in the past, even though data on long-term alcohol consumption and risk is less clear.
For this study, all patients arriving at an arrhythmia clinic at Charing Cross Hospital in London with symptoms of a new cardiac arrhythmia were asked about their weekly alcohol consumption.
Participants were grouped according to how much they drank: teetotaler (those who abstained completely), moderate drinkers (1-14 units per week for females and one to 21 units per week for males) and excessive (anything greater than moderate). In the study, two units were about equal to one pint of beer.
Those with confirmed atrial fibrillation were then compared to those without the irregular heart beat. About half (48 percent) of people in each group were moderate drinkers, suggesting no increase in risk. Excessive drinking, however, was much higher in patients with atrial fibrillation than in patients without (27 percent versus 17 percent, respectively).
In fact, these heavy drinkers raised their risk of atrial fibrillation by 2 percent for each additional unit they drank compared to non-drinkers.
It's not clear how alcohol and rhythm disturbances might be linked, but the experts offered up some theories.
One is that heavy drinking ramps up the body's "fight-or-flight" response, Erwin said. Another is that drinking can raise the level of fatty acids in the bloodstream.
"Several mechanisms have been suggested from very small studies, including the high adrenaline state of drinking and alcohol withdrawal and impaired vagal heart rate control," Martins said.
Cutting down on drinking could lower the risk, he said.
"We found that nearly one in five of all 984 patients that we evaluated in our study admitted to drinking more than the recommended level," Martins said. "If this behavior could be modified, one might speculate that it could potentially result in a significant reduction in the number of new AF cases."
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