Archive for 2003
Latest Research on Atkins Diet
In May the New England Journal of Medicine published two new studies looking at the Atkins Diet which, oddly enough, received diametrically different spin from different news agencies.
Here’s how the Associated Press covered the new studies,
Atkins Diet Bolstered by Two New Studies
A month after Dr. Robert C. Atkins’ death, his much-ridiculed diet has received its most powerful scientific support yet: Two studies in one of medicine’s most distinguished journals show it really does help people lose weight faster without raising their cholesterol.
But here’s how Reuters covered the exact same story,
Atkins Diet May Be No Better Than Just Cutting Fat
Shunning starchy foods in favor of meat and fat helps obese people shed some weight faster than a standard low-fat diet, but over time there may not be a big difference, researchers said on Wednesday.
In reality, these two studies really did little more than affirm previous research about the Atkins Diet. Can you lose weight on the Atkins Diet? Absolutely, especially in the short term. But in the long term, as with most fad diets, people tend to give up on the diet and/or weight loss tends to stop.
The two studies tracked people on the Atkins Diet for 6 months and 12 months. In the 6 month study, people on the Atkins Diet lost 13 pounds compared to just 4 pounds for people on a low-fat diet. But in the 12 month study, there was no significant difference in total weight loss between the two groups.
On the other hand, while showing that people can lose weight on a high protein diet, this just reinforces the likelihood that what is really going on is simply that people on these diets are simply switching from high calorie high carbohydrate diets to low calorie high protein diets. The Atkins nonsense about needing to cut carbs to burn fat is simply that — nonsense.
The magic formula for losing weight remains the same — increase exercise and reduce calories.
Sources:
Atkins diet bolstered by two new studies. Associated Press, May 21, 2002.
Atkins diet may be no better than just cutting fat. Reuters, May 21, 2002.
Tags: Uncategorized
Marin County Breast Cancer Data Faulty
Back in March, this site noted the controversy over breast cancer rates in Marin County, California. Marin County is one of the wealthiest counties in the United States and also has one of the highest breast cancer rates — 198 cases per 100,000 population compared to a national average of 139 per 100,000 for the rest of the country.
Activists who believe that pollution is a major contributor to breast cancer seized on this cancer cluster as evidence for their views, although a number of alternative explanations were possible. But now it turns out that there is an even better explanation — the data that claimed Marin County had a breast cancer incidence of 198 cases per 100,000 population appears to have been faulty.
The faulty data came to light after research in 2002 said that the rate of cancer for white women in Marin County had increased from 191 cases per 100,000 in 1998 to 230 cases per 100,000 in 1999. That sort of massive jump was extremely suspicious.
It turns out that such estimates had been using faulty data from the U.S. Census Bureau that dramatically undercounted the population of women in Marin County. Census data from 2000 showed that the 1990 estimates that such studies had been using underreported the number of white women 45-64 in Marin County by close to 20 percent. Revised breast cancer rates have not been released.
Ironically, another recent study of breast cancer among women in Marin County will also not please the activist who want pollution to be the cause and accuse researchers of “blaming the victim” anytime another cause is put forward.
A study by researchers at the University of California, San Francisco and published in the online journal Breast Cancer Research found a strong correlation between alcohol consumption and breast cancer among women in Marin County. Women who consumed two drinks a day had twice the breast cancer risk, and the risk increased with self-reported alcohol consumption.
That study was small, comparing 285 Marin County women with breast cancer to 286 healthy women living in the county. But it did find no correlation between breast cancer and length of time living in Marin County, suggesting the high breast cancer rate in Marin County has something to do with a confounding factor that women there share rather than something to do with Marin County itself.
Source:
Marin County breast cancer rates not as high as once thought. Justin Pritchard, Associated Press, April 4, 2003.
Study: Marin breast cancer related to alcohol consumption. Associated Press, May 7, 2003.
Tags: Cancer
Death Rate Among Anorexia Nervosa Patients Exaggerated
A Mayo Clinic study that looked at mortality rates among patients with anorexia nervosa over a period of 60 years concluded that people diagnosed with the disorder die at the same rate as people who do not have the disorder. This contradicts both previous clinical studies as well as many commonly cited claims that the death rate for people with the disorder is extremely high.
The commonly repeated claim is that individuals with anorexia nervosa have a mortality rate that is an astounding 12 times higher than the general population. But, as an epidemiologist with the Mayo Clinic points out, that is because previous studies were generally conducted in hospital settings where individuals with the most advanced cases of the disorder would be overrepresented.
Searching medical records, the Mayo Clinic identified 208 patients who met the criteria for an anorexia nervosa diagnosis between 1935 and 1989. The researchers found that those patients had the same death rate as the general population.
Mayo Clinic epidemiologist Joseph Melton said that,
Although our data suggest that overall mortality is not increased among community patients with anorexia nervosa in general, these findings should not lead to complacency in clinical practice because deaths do occur.
Patrick Sullivan, a professor of psychiatry and genetics at the University of Carolina at Chapel Hill, wrote in an editorial accompanying the study that what it showed was that anorexia nervosa symptoms occurred along a spectrum. Those with the most severe cases — such as those requiring hospitalization — may indeed have a higher mortality rate, but it is important to make distinctions between the degree of severity of the disease rather than lumping all cases in with the most severe and claiming that anyone with the disorder has a 12 times higher mortality rate.
Source:
Death rate for eating disorder not unusual. Brad Evenson, National Post (Canada), March 12, 2003.
Tags: Uncategorized
British Study Concludes There Is No Gulf War Syndrome
Great Britain’s government-funded Media Research Council released a study in May looking at all available scientific research on the health of British veterans of the first Persian Gulf War. It concluded that there is simply no single Gulf War Syndrome.
The MRC report concludes,
There is no unique Gulf War Syndrome. . . . In short there is no evidence from UK orientational research for a single syndrome related specifically to service in the Gulf.
. . .
The only common Gulf conflict-related experiences seem to involve ill veterans’ perception of their health. Gulf veterans do have an increased risk of post-traumatic stress disorder but it only affects around 3% of them, which is not enough to explain all Gulf veterans’ illnesses. Depression and alcohol are much more important health risk factors.
The report did find that Gulf War veterans were at an increased risk of post-traumatic stress disorder
Sources:
Gulf War Syndrome ‘does not exist’. The BBC, May 25, 2003.
No Such Thing As Gulf Syndrome, Say Scientists. Western Mail and Echo, May 26, 2003.
Gulf Syndrome ‘Does Not Exist’. Sunday Mercury, May 25, 2003.
Official: Gulf Syndrome ‘is a myth’. Colin Brown, Sunday Telegraph (London), May 25, 2003.
Veterans’ Anger At Doctors’ Attack On Gulf War Sickness Crusade. Western Daily Press, May 26, 2003.
Tags: Gulf War Syndrome
Just What the World Needed: The Bible Code II
Michael Shermer has an interesting article in the June 2003 issue of Scientific American on probably one of the most pointless book sequels ever — The Bible Code II which is currently riding the New York Times bestseller list. For those unfamiliar with Michael Drosnin and his first book, The Bible Code, Shermer provides a short summary of Drosnin’s method,
According to proponents of the Bible Code–itself a subset of the genre of biblical numerology and Kabbalistic mysticism popular since the Middle Ages–the Hebrew Pentateuch can be decoded through an equidistant-letter-sequencing software program. The idea is to take every nth letter, where n equals whatever number you wish: 7, 19, 3,027. Print out that string of letters in a block of type, then search left to right, right to left, top to bottom, bottom to top, and diagonally in any direction for any interesting patterns. Seek and ye shall find.
In other words, turn the Bible into one giant word search and then look for words that supposedly prophesied recent events.
Dave Thomas (the physicists not the dead Wendy’s founder), has a blistering looking at just how foolish Bible Code-style efforts are. As Thomas notes, this can be done to any text to produce pretty much whatever the person doing the looking wants to see.
Thomas applied that method to The Bible Code itself to produce this message hidden in the text of Droslin’s first book,
“THE BIBLE CODE IS A SILLY, DUMB, FAKE, FALSE, EVIL, NASTY, DISMAL FRAUD AND SNAKE-OIL HOAX.”
As Droslin notes, this in and of itself is enough to falsify Droslin’s claims for the gullible who still believe it (emphasis added),
What does the puzzle above prove? It shows, once again, that detailed interlocking puzzles for ANY desired message can be harvested from ANY text, and not just from the Bible. This directly contradicts Drosnin’s false assertion from his first Bible Code book: “Consistently, the Bible Code brings together interlocking words that reveal related information. With Bill Clinton, President. With the Moon landing, spaceship and Apollo 11. With Hitler, Nazi. With Kennedy, Dallas. In experiment after experiment, the crossword puzzles were found only in the Bible. Not in War and Peace, not in any other book, and not in 10 million computer-generated test cases.”
Still, I predict that this will hardly stop Droslin from scoring more success with the inevitable Bible Code III in a few years.
Sources:
Codified Claptrap: The Bible Code is numerological nonsense masquerading as science. Michael Shermer, Scientific American, June 2003.
The Bible Code. Dave Thomas, New Mexicans for Science and Reason, undated. Accessed: June 4, 2003.
Tags: Uncategorized
The Ideology Goes On Before the Data Comes In
Sydney Smith wrote an interesting look at activists and others who complain that food and food alone is responsible for the increasing rate of obesity in America that notes they are missing a major component of obesity — lack of exercise.
As Smith points out, the data simply do not back up the claim that Americans weigh more because they are eating more — rather, it appears that Americans have simply stopped exercising as much as they used to,
The average daily caloric consumption of Americans is not far from the recommended rates of 1800 to 2200 calories a day (depending on age and sex.) On the other hand, less than ten percent of schools set aside time for physical education each day, and less than 40 percent of adults engage in enough physical activity to confer health benefits. With numbers like that, our waist lines will continue to expand, no matter what we eat.
A recent study of teenagers’ habits over the past twenty years supports this observation. Nutritionist Lisa Sutherland of the University of North Carolina at Chapel Hill looked at data from the CDC’s National Health and Nutrition Examination Survey and Youth Risk Behavior Surveillance System, and the Department of Agriculture’s Nationwide Food Consumption Survey, all of which have been following our national weight trends, activity trends, and food consumption trends for several years. She found that over the past twenty years, teenagers have, on average, increased their caloric intake by one percent. During that same time period, the percentage of teenagers who said they engaged in some sort of physical activity for thirty minutes a day dropped from 42 percent to 29 percent. Not surprisingly, teenage obesity over the twenty year period increased by 10 percent. The logical conclusion is that it isn’t junk food that’s making teenagers fat - it’s their lack of activity.
But the kicker is the quote that Smith digs up from Dr. Nancy Krebs, the chair of the American Academy of Pediatrics’ committee on nutrition about the study of teenagers. Krebs was quoted by the Associated Press as saying,
We are pretty sure they are eating too much, no matter what the data say.
Well sure. And psychics are certain that they are able to reliably predict events no matter what the data (and those horrible skeptics and debunkers) say. If you throw out a need for data and just go with the “pretty sure” standard of evidence, a lot of things just fall into place.
Source:
‘No Matter What the Data Say. Sydney Smith, TechCentralStation.Com, May 29, 2003.
Tags: Uncategorized
Does Eliminating Secondhand Smoke Cut Heart Attack Rates?
One of the sillier junk science claims so far this year was the release of a study that claimed a ban on smoking in Helena, Montana, cut heart attacks in that city by half. I first heard of the widely publicized study in an National Public Radio report that made it sound as if this were sound science, but a close look at the study is more than enough to fall apart.
First, the study is still unpublished and has not been subjected to any sort of peer review.
Second, the study uses obviously questionable methodology. One of the things commonly omitted from many media reports was just how small of a sample size was involved. A finding that heart attacks were cut in half sounds impressive until you look closer and find that we’re talking about an area that averaged seven heart attacks a month from 1998-2001. During the six month smoking ban, heart attacks dropped to an average of 4 per month. The value of such small sample size is highly questionable, but doesn’t stop researcher Stanley Glantz from declaring in a press release on the study that,
This striking find suggests that protecting people from the toxins in secondhand smoke not only makes life more pleasant; it immediately starts saving lives.
As Jacob Sullum noted in an excellent analysis of the study for Reason,
A little calculation shows how preposterous this claim is, even if you believe that secondhand smoke causes heart disease. The American Heart Association attributes 35,000 heart disease deaths a year, about 5 percent of the total, to secondhand smoke.
It seems reasonable to assume that the proportion would be similar for heart attacks, fatal or not. So even if a city completely eliminated secondhand smoke (which Helena’s ban did not do, since it did not apply to smoking at home), how could that possibly cut heart attacks in half?
Sargent and Glantz note that smoking bans also encourage smokers to cut back or quit. Inconveniently for them, that point suggests that any drop in heart attacks could be due to less smoking rather than less exposure to secondhand smoke.
In any case, the numbers still don’t add up. According to the U.S. Centers for Disease Control and Prevention, smoking accounts for about one-fifth of heart disease deaths. So even if every smoker in Helena quit (which no one claims happened), you would not get anything like the drop that Sargent, Shepard, and Glantz attribute to the ban.
Sullum also notes that no other locality that has enacted similar bans on smoking has seen any significant drop in heart attacks. California, for example, enacted a workplace smoking ban in 1995 and has not seen the sort of large scale declines in heart attacks that should have followed if Glantz’s research was describing a real effect.
What about large scale studies of smoking bans? A large-scale study published in the British Medical Journal suggests that there is no “causal relation between tobacco smoke and tobacco related mortality . . .”
James E. Enstrom, of the University of California at Los Angeles and Geoffrey C. Kabat of the State University of New York at Stony Brook, used survey data from the American Cancer Society that followed 118,000 Californians from 1960-1998.
That study, too, was attacked as being politically motivated. The researchers apparently received money from the tobacco industry, and the American Cancer Society and others complained that the researchers went beyond what the data can say.
The ultimate problem, of course, which tends to get glossed over is the difficulty in accurately determining just how much passive smoke people have been exposed to.
Sources:
Do smoking bans cut heart attacks in half? Jacob Sullum, Reason, April 4, 2003.
Second-hand Smoke Study Sparks Controversy. Mike Wendling, May 16, 2003.
Tags: Second Hand Smoke
Does Traffic Pollution Lead to Poor Quality Sperm?
Italian researchers published a study in “Human Reproduction” in April suggesting that men exposed to exhaust fumes from traffic had higher sperm motility than men not exposed to exhaust fumes. But the study is a classic example in the pitfalls of confounding factors.
Specifically, their study looked at men who worked at toll booths. Guess what men who work at toll booths do? They sit for up to six hours a day. Guess what one factor that can contribute to reduced sperm count is? That’s right, prolonged sitting.
Now, the researchers claim they took this into account by using a control group that included clerks, students, doctors and drivers who have largely sedentary jobs that involve a lot of sitting. But unless toll booths in Italy include significantly different accommodations than toll booths here in the United States, six hours sitting at a toll both is not quite comparable to six hours of sitting in an office chair.
The study was also very small, involving an experimental group of 85 men and a control group of 85 men. None of which prevented the study from concluding based on their findings that, “Health authorities should be alert to the insidious health effects of environmental pollution.”
A better lesson might be to avoid drawing such unwarranted conclusions from a single small study whose results are as likely explained by confounding factors as by the effects of pollution.
Sources:
Traffic pollution damages men’s sperm. NewScientist.Com, April 30, 2003.
Traffic ‘damages male fertility’. The BBC, April 30, 2003.
Tags: Miscellaneous Health Scares
Is MMR Associated With an Increase in Neurological Disorders?
Well, here comes the latest round in the MMR vaccine hysteria. A study published in International Pediatrics reports that the MMR vaccine is associated with an increase in neurological disorders. But the study falls apart like tissue paper upon closer examination.
The primary problem with the study is its very design. The study compared estimates of adverse reactions among children after they were given MMR to adverse reactions after the administration of the DTP shot. But the problem here should be obvious — the MMR is given significantly later in life, so of course more children will be diagnosed with neurological disorders after receiving the MMR than the DTP.
Specifically, the DTP is given at 2, 4 and 6 months of age, whereas the MMR is typically given somewhere in the 15-18th month of life. As Dr. Mary Ramsay of the UK’s Health Protection Agency told the BBC,
The authors have estimated the rate of reported adverse reactions following MMR (given at 15-18 months of age) and compared this to the estimated rates of the same conditions reported following DTP vaccination (given at 2, 4 and 6 months) of age.
Regardless of the other weaknesses of the data, the failure to compare children of the same age is enough to explain the apparent excess of cases reported in the MMR group.
Meanwhile, the BBC reports that in 2002 there were 310 cases of measles in the UK — the most in a single year since the 1988 introduction of the MMR vaccine, so the vaccine hysteria is accomplishing something at least.
Source:
Concern over MMR safety study. The BBC, May 19, 2003.
Tags: Vaccination
Activists Want Ban on DTP Shot
Campaigners in Great Britain have called for a ban on the diptheria, tetanus and pertusis or whipping cough vaccine. The vaccine is usually given to infants in the second month of life.
Although there is no evidence linking the DTP vaccine to any ill health effects, Action Against Autism urged the British government to ban the vaccine because it uses thiomersal as a preservative. Thiomersal contains small amounts of mercury which some groups have claimed contribute to or cause autism.
The British Department of Health responded to the suggested ban by saying,
All vaccines are tested for their safety and efficacy. Recent reviews by the Committee on the Safety of Medicines and the US Institute of Medicine found no evidence of any effect of low doses of thiomersal on childhood development.
British Prime Minister Tony Blair also publicly rejected banning the DTP vaccine, saying there was no evidence that it was unsafe.
Source:
Fresh fears over child vaccines. The BBC, January 14, 2003.
Tags: Vaccination