Friday, May 30, 2008

Can aspirin help to prevent breast cancer?

Don't rely on it. The popular article below does not say where they got their info from but I presume this study from some years back has now reached journal publication somewhere. And it is just the usual epidemiological muck. A weak correlation is found -- in this case, taking aspirin reduced your risk from 1.7% to 1.5% or thereabouts -- and a simple causal inference is immediately declared "ex cathedra". The fact that women who regularly take aspirin might differ from women who do not in all sorts of ways is completely ignored. If there is any meaning in the findings at all, they probably mean that middle class women take more aspirin

Lurking in bathroom cabinets and medicine chests across the land is a wonder drug: aspirin. Over the past two decades, the mild painkiller has been used against rheumatoid arthritis, strokes and heart attacks, and has been shown to protect nerves, fight a virus linked with birth defects, inhibit a protein that enables the Aids virus to multiply, and help treat adult-onset diabetes.

Researchers have also suggested the drug may help prevent bowel, pancreatic and lung cancer, and a team in Italy has reported that taking regular doses for five years or more can cut the risk of cancers of the mouth, throat and oesophagus by two thirds.

This week, the drug's superstar status was confirmed by an American study of more than 80,000 women which concluded that regular use of aspirin and ibuprofen can hinder the formation and growth of breast cancer, cutting the risk by up to half. Aspirin must now count as one of the greatest finds in medical history.

The history of its use stretches back thousands of years. A collection of medicinal recipes from the second millennium BC recommended treating rheumatic and back pain with an infusion of dried myrtle leaves, which contain salicylic acid, a close chemical relative of aspirin. In the fifth century BC, Hippocrates prescribed extract of willow-tree bark for fever and labour pains. Again, the active substance is salicylic acid. By the late 1800s, salicylates had become the standard drug for treating arthritis, but they irritated the stomach. Enter Felix Hoffman who, working for the German company Bayer & Co, set out to find a less irritating medicine for his father's arthritic pain. In 1897, he created acetylsalicylic acid. Aspirin was born.

By 1950, aspirin was the best-selling painkiller, but it was not until 1971 that doctors discovered the drug's secret. British pharmacologist Sir John Vane found that aspirin worked by inhibiting hormone-like chemicals that play a role in pain and inflammation and regulate blood flow.

Around 50,000 tons of aspirin are now made annually. In the wake of this week's headlines, that amount looks likely to grow further. The new findings emerge from the Women's Health Initiative, a US government study started more than a decade ago to track diseases such as cancer. The data reveals that taking two or more tablets of aspirin and other so-called non-steroidal anti-inflammatory drugs - NSAIDs - a week has a significant effect in reducing the risk of developing breast cancer.

Most of the women were taking aspirin and ibuprofen for arthritis, muscle pain or headaches. Regular use of the drugs for five to nine years reduced the participants' risk of developing breast cancer by 21 per cent, according to Prof Randall Harris of Ohio State University and his team. He was "amazed" by these results, which held good when confounding factors, such as age, weight and exercise, were taken into account. Extending the use of NSAIDs to 10 or more years resulted in an even greater reduction of 28 per cent. The researchers observed that ibuprofen was more effective than aspirin in preventing breast cancer (49 per cent versus 21 per cent reduction in risk). Small doses did not have any significant effect. "There is compelling and converging evidence to indicate that NSAIDs may have protective effects against breast cancer and other forms of cancer," says Prof Harris.

Aspirin is what pharmacologists call a "dirty" drug - it has many different actions because it binds to many molecular targets in the human body. In the case of cancer prevention, the key target is the cyclo-oxygenase enzyme COX-2, the trigger of pain and inflammation, which is made in abnormally high amounts in most human breast cancers. Recent studies indicate that COX-2 may be implicated in several events in tumour development.

Given that breast cancer is the most common form of cancer, affecting about one in 10 women in Britain, should all women now start taking aspirin? Certainly not in the case of very young women: last year, the then Medicines Control Agency warned that children under the age of 16 should not take the drug because of links with Reye's syndrome, a very rare but potentially fatal condition that affects the brain and liver in children and adolescents.

However, Prof Harris believes the new evidence is "so compelling" that women over 40 might consider taking aspirin or ibuprofen regularly - but only after consulting their GP, because there is a risk of side effects, such as indigestion, ulcers and gastrointestinal bleeding.

The drug could become an important part of cancer prevention, agrees Dr Richard Sullivan, head of clinical programmes for Cancer Research UK. However, he stresses that scientists now need to weigh up how many women could be prevented from getting breast cancer and how many could suffer fatal side effects from taking these drugs. "Aspirin has to count as one of the greatest finds in the history of drug discovery," he says. "However, we're not yet at the stage where we can recommend that everyone starts taking aspirin on a daily basis to protect against breast cancer, as we'll need to further investigate its effectiveness and the possible side effects of long-term use."


Energy drinks linked to risky behavior among teenagers

That stimulants stimulate all sorts of behaviour -- both good and bad -- should not be a big surprise

Health researchers have identified a surprising new predictor for risky behavior among teenagers and young adults: the energy drink. Super-caffeinated energy drinks, with names like Red Bull, Monster, Full Throttle and Amp, have surged in popularity in the past decade. About a third of 12- to 24-year-olds say they regularly down energy drinks, which account for more than $3 billion in annual sales in the United States.

The trend has been the source of growing concern among health researchers and school officials. Around the country, the drinks have been linked with reports of nausea, abnormal heart rhythms and emergency room visits.

In Colorado Springs, several high school students last year became ill after drinking Spike Shooter, a high caffeine drink, prompting the principal to ban the beverages. In March, four middle school students in Broward County, Florida, went to the emergency room with heart palpitations and sweating after drinking the energy beverage Redline. In Tigard, Oregon, teachers this month sent parents e-mail alerting them that students who brought energy drinks to school were "literally drunk on a caffeine buzz or falling off a caffeine crash."

New research suggests the drinks are associated with a health issue far more worrisome than the jittery effects of caffeine risk taking. In March, The Journal of American College Health published a report on the link between energy drinks, athletics and risky behavior. The study's author, Kathleen Miller, an addiction researcher at the University of Buffalo, says it suggests that high consumption of energy drinks is associated with "toxic jock" behavior, a constellation of risky and aggressive behaviors including unprotected sex, substance abuse and violence.

The finding doesn't mean the drinks cause bad behavior. But the data suggest that regular consumption of energy drinks may be a red flag for parents that their children are more likely to take risks with their health and safety. "It appears the kids who are heavily into drinking energy drinks are more likely to be the ones who are inclined toward taking risks," Miller said.

The American Beverage Association says its members don't market energy drinks to teenagers. "The intended audience is adults," said Craig Stevens, a spokesman. He says the marketing is meant for "people who can actually afford the two or three bucks to buy the products."

The drinks include a variety of ingredients in different combinations: plant-based stimulants like guarana, herbs like ginkgo and ginseng, sugar, amino acids including taurine as well as vitamins. But the main active ingredient is caffeine. Caffeine content varies. A 12-ounce serving of Amp contains 107 milligrams of caffeine, compared with 34 to 38 milligrams for the same amount of Coca-Cola or Pepsi. Monster has 120 milligrams and Red Bull has 116. Higher on the spectrum, Spike Shooter contains 428 milligrams of caffeine in 12 ounces, and Wired X344 contains 258.

Stevens points out that "mainstream" energy drinks often have less caffeine than a cup of coffee. At Starbucks, the caffeine content varies depending on the drink, from 75 milligrams in a 12-ounce cappuccino or latte to as much as 250 milligrams in a 12-ounce brewed coffee.

One concern about the drinks is that because they are served cold, they may be consumed in larger amounts and more quickly than hot coffee drinks, which are sipped. Another worry is the increasing popularity of mixing energy drinks with alcohol. The addition of caffeine can make alcohol users feel less drunk, but motor coordination and visual reaction time are just as impaired as when they drink alcohol by itself, according to an April 2006 study in the medical journal Alcoholism: Clinical and Experimental Research.

"You're every bit as drunk, you're just an awake drunk," said Mary Claire O'Brien, associate professor in the departments of emergency medicine and public health services at Wake Forest University Baptist Medical Center in Winston-Salem, North Carolina

O'Brien surveyed energy drink and alcohol use among college students at 10 universities in North Carolina. The study, published this month in Academic Emergency Medicine, showed that students who mixed energy drinks with alcohol got drunk twice as often as those who consumed alcohol by itself and were far more likely to be injured or require medical treatment while drinking. Energy drink mixers were more likely to be victims or perpetrators of aggressive sexual behavior. The effect remained even after researchers controlled for the amount of alcohol consumed.

Energy drink marketers say they don't encourage consumers to mix the drinks with alcohol. Michelle Naughton, a spokeswoman for PepsiCo, which markets Amp, said, "We expect consumers to enjoy our products responsibly."


1 comment:

Karl said...

Energy drinks:

There is a website called Death by Caffeine which estimates the number of servings of your favorite caffeinated drink it would take to kill you.

According to this page, a 200-lb person could survive drinking 303 diet Cokes. It would take just over 85 cans of Monster or Rockstar, 170 cans of Red Bull, and almost 95 cans of Full Throttle.

So it goes....