Friday, June 09, 2006

Corpus Callosum Has Gone To Seed

As of now, Corpus Callosum will no longer be published on blogspot. The new location is at ScienceBlogs, sponsored by Seed Media Group, publishers of Seed Magazine.

Photo by Tennessee-Gator
Licence: Creative Commons, Attribution-NonCommercial-NoDerivs 2.0

Thursday, June 08, 2006

Today's Lesson?

The two big news items today are : 1) the killing of Abu Musab al-Zarqawi, and 2) the sharp decline in stock markets around the world.  The two are not particularly related.

The juxtaposition of these two events creates an interesting perspective.  While it is good news that Zarqawi is out of action, it is bad news that the stock markets around the world are struggling.  The thing is, the good news does not have any direct effect on the quality of life here in the USA, while the bad news does have a direct domestic effect.  How bad the negative effect will be remains to be seen.  I'm not arguing that the economic news is dire; rather, I am saying that this juxtaposition of events may highlight the relative importance of the two.  It is going to be hard for people to care about an incremental improvement in Iraq, when their own retirement funds are going in the tank.

"They Must Actually Take Their Medication"

A new report indicates that treatment with calcium and vitamin D might actually reduce the incidence of hip fractures.  This appears to contradict some other studies that were reported widely in the popular media.  
Dr. Boonen presented results of a meta-analysis of major randomized placebo-controlled trials that analyzed the effects of vitamin D alone or in combination with calcium. The meta-analysis found that in patients getting 800 units of vitamin D and more than 1,000 mg of calcium a day, there was a 21% reduction in risk of fracture compared to placebo.
The new report was a meta-analysis, meaning that the authors pooled the results of several studies.  As seen in Wikipedia:
In statistics, a meta-analysis combines the results of several studies that address a set of related research hypotheses. The first meta-analysis was performed by Karl Pearson in 1904, in an attempt to overcome the problem of reduced statistical power in studies with small sample sizes; analyzing the results from a group of studies can allow more accurate data analysis.
To give an idea of why the meta-analysis might be more valid than the other studies, the authors point out:
For one thing, he said, neither study had enough statistical power to find an effect. For instance, he said, the RECORD trial, looking at hip fractures, had 2,649 participants and only 93 events. By contrast, Dr. Boonen said, he and his colleagues had a patient pool of 16,978 individuals and 812 fractures.
I'm not sophisticated enough with statistics to be able to give an opinion of the validity of this particular analysis, and the report I am citing here has not yet been subjected to peer review.  Therefore, the results are to be considered to be preliminary.  

What is interesting is the list of reasons given, for why the meta-analysis gives results that are different than the previously-reported studies.  It turns out that the positive effect is seen only in those patients who actually had a deficiency of either calcium or vitamin D.  If the patient's regular diet provides enough of those nutrients, there is no effect from supplements.   Some patients in the studies did not take doses that were high enough.  Some did not take both the calcium and the vitamin D.  Also, the prior reports included in the analysis patients who did not actually take the supplements at all:
Dr. Boonen told reporters after his presentation that clinicians need to pay attention to four factors. They must prescribe a combination of calcium and vitamin D, the doses must be high enough, the patients must be in need of the supplements, and finally they must actually take their medication.
It seems kind of obvious to say that the patients actually have to take the supplements in order to see an effect, but in daily practice, noncompliance turns out to be a common problem.  Sometimes the factors that seem too obvious to even consider, are the ones that turn out to be important.

Monday, June 05, 2006

Is This One For Real?

The LA Times (free registration required) has an article on the possibility of a shortage of physicians in the USA:
Physician Shortage Looms, Risking a Crisis, as Demand for Care Explodes
An aging America needs more doctors, but supply isn't keeping up. Experts fear worsening quality and dangerously long waits for appointments.
By Lisa Girion, Times Staff Writer
June 4, 2006

A looming doctor shortage threatens to create a national healthcare crisis by further limiting access to physicians, jeopardizing quality and accelerating cost increases.

Twelve states — including California, Texas and Florida — report some physician shortages now or expect them within a few years. Across the country, patients are experiencing or soon will face shortages in at least a dozen physician specialties, including cardiology and radiology and several pediatric and surgical subspecialties.

The shortages are putting pressure on medical schools to boost enrollment, and on lawmakers to lift a cap on funding for physician training and to ease limits on immigration of foreign physicians, who already constitute 25% of the white-coated workforce.

But it may be too late to head off havoc for at least the next decade, experts say, given the long lead time to train surgeons and other specialists. [...]
The biggest issue there is the funding for medical training.  It is incredibly expensive to train physicians.  I recall that when I was in medical school, and students were complaining about double-digit increases in tuition, one of the administrators told us that our tuition only covered about one-third of the actual cost of training.  As an historical aside:
First UM Medical buildingWhen the Medical School first opened in 1850, students paid only a $10 registration or matriculation fee.

By 1891, the matriculation fee was $10 for Michigan residents and $25 for students from out of state. Over the next 50 years, tuition rose slowly until it was $250 in 1940. In the early part of the twentieth century, students were required to pay laboratory and demonstration fees totaling $136 over the four years. None of this takes into account room and board. The average cost of room and board in 1893 was $3-$5 a week; 1931: $12-15 a week. In 2003, tuition and fees for Michigan residents were $20,526 (out of state, $31,526) and estimated living expenses were $20,300 a year. Currently, the average student debt for someone receiving an M.D. degree from the University of Michigan is close to $100,000.
Medical schools are allowed to charge more for services, based upon the recognition of the fact that training costs are high.  But the federal government has balked at these higher fees, so there have been caps.  This debatable policy has made it more difficult for medical schools to expand enrollment.

There have been dire warnings of physician shortages before, but this time it seems more credible to me.  The key factor is the fact that the average age of the US population is increasing.  Obviously, older people require more doctoring than younger people.  But there is another factor:
At the same time, younger male physicians and women — who constitute half of all medical students — are less inclined to work the slavish hours that long typified the profession. As a result, the next generation of physicians is expected to be 10% less productive, Edward Salsberg, director of the Assn. of American Medical Colleges' Center for Workforce Studies, told a congressional committee in May.
I expect that the trend toward fewer work hours will bring up some controversy, and possibly some resentment.  Some physicians will be negatively judgmental about those who choose to work fewer hours.  Others will face pressures to delay their retirement.  At the same time, it will be increasingly difficult for physicians to keep up-to-date with their skills and knowledge base.  Every hour spent on continuing education is an hour that is not devoted to patient care.  There is a risk that the demand for more patient-care hours could lead to doctors devoting less time to continuing education, which obviously would have a detrimental effect on quality.

It seems likely that the prediction of a shortage of physicians is accurate.  That will pose new challenges for physicians, in terms of managing stress.  It occurs to me as I write this, that it may be desirable to make a point of educating medical students about these pressures, and how to deal with them.  As soon as I figure out how to deal with them, I will post that information here.

Sunday, June 04, 2006

What To Do On 6/6/6

There is still time to make your plans:
Hell plans devil of a time on 6/6/06

June 4, 2006

HELL, Mich. -- They're planning a hot time in Hell on Tuesday.

The day bears the date 6/6/06 -- abbreviated as 666, it is the "number of the beast" according to the Bible's Book of Revelation, often linked to the devil or the Antichrist.

And there's not a snowball's chance in Hell the day will go unnoticed in the unincorporated hamlet 60 miles west of Detroit.

Nobody seems more fired up than John Colone, the town's self-styled mayor and owner of a souvenir shop.

''I've got '666' T-shirts and mugs. I'm only ordering 666 so once they're gone, that's it,'' said Colone, also known as Odum Plenty. ''Everyone who comes will get a letter of authenticity saying you've celebrated June 6, 2006, in Hell.''

Not all 'Hell-billies' happy

Most of Colone's wares will sell for $6.66, including deeds to one square inch of Hell.

Mike ''Smitty'' Hickey, owner of Dam Site Inn, wasn't sure what kind of clientele would show up Tuesday.

''I don't think we're going to get the cult crowd, the devil worshippers or anything like that,'' Hickey said.

Jason LeTeff, one of the town's 72 year-round residents -- or, as the mayor calls them, Hellions or Hell-billies, wasn't enthused.

''Now, here I am living in Hell, taking my kids to church and trying to teach them the right things and the town where we live is having a 6-6-6 party,'' he said.
More information on Hell, here.

War on Science Update

Seed Magazine, the originator of the web's largest conversation about science, has an editorial: The American War on Science.  There have been many such articles lately, but this one is different.  It examines the logistical aspect of the war.  By that, I mean that the author, Christopher Mims, discusses the complex issues involved in the supply of scientists, mathematicians, and engineers in the USA.  
It is possible that American students' accelerating disinterest in science and engineering, coupled with a dwindling supply of foreign replacements, would set up a Peak Oil-type scenario in the US, where demand for these workers continues to grow while supply plateaus and then dwindles.
There is another issue that is peripherally related to this: The Undercover Activist Blog, a blog that allows public employees to post anonymous criticisms of their agencies and governmental activities, has posted some new information (1 2) about the industry push to get controversial pesticides approved by the FDA.  
EPA scientists protest pending pesticide approvals

In a PEER-released May 24th letter to the U.S. Environmental Protection Agency, leaders from three unions representing 9,000 scientists, risk managers and other specialists are publicly objecting to imminent agency approval for a score of powerful, controversial pesticides.

The letter is in reference to an August 3, 2006 deadline for the EPA to issue final tolerance approval for 20 organophosphate and carbamate pesticides. The scientists cite “compelling evidence” which EPA leadership is choosing to ignore that these “pesticides damage the developing nervous systems of fetuses, infants and children.”

Today’s Wall Street Journal article (subscription) broke the story and cites political pressure by agency managers and pesticide-industry officials to allow the continued use of a family of pesticides that might be harmful to children, infants and fetuses. The letter asks EPA Administrator Stephen Johnson to either adopt maximum exposure protections for these agents or take them off the market.
It seems ironic that persons who advocate for a "culture of life" would want to make it legal to poison fetuses.  Of course, no one is saying that these pesticides actually kill fetuses, just that they damage their brains.  The real irony is that it is going to be a lot harder to keep up the supply of scientists and science teachers, if we poison their developing brains.

Saturday, June 03, 2006

Cheslea Painters Art Show

In Chelsea, Michigan, the Chelsea Painters are having their annual art fair. It is closed for today, but will be up again tomorrow from 10 AM to 5 PM.

It's on the grounds of Chelsea Community Hospital (map), about 20 miles west of Ann Arbor.

Friday, June 02, 2006

A Skeptic's View of "Viagra for Diabetic Women"

OK, this synopsis does not contain much actual information; certainly, not enough to be useful as a basis for medical decisions.  But it does provide an example to illustrate the process of skeptical thinking.  It's from Medscape News (free registration required -- but it's worth the hassle).
Sildenafil May Improve Sexual Functioning in Diabetic Women
NEW YORK (Reuters Health) May 31 - Premenopausal women with type 1 diabetes with sexual dysfunction may find that sildenafil improves arousal, orgasm and sexual enjoyment and decreases pain during intercourse, results of a small pilot study suggest. [...]

To test their theory, they recruited 32 women with type 1 diabetes who in the past had experienced normal sexual desire within their heterosexual relationship, but currently experienced sexual dysfunction -- for 3.5 years on average. [...]

Sildenafil was associated with significantly improved arousal, orgasm, and enjoyment compared with baseline (p < 0.001 for each). Compared with placebo, the experience of arousal (p < 0.01) and orgasm (p < 0.05) were better during active treatment. Only desire and frequency did not change significantly in either group. [...]
Note: is the generic name for .

The original study can be found here, but you need subscription-level access or a bunch of money (that you have no other use for) in order to read the text.

There are a couple of points that one needs to consider in interpreting a study such as this.  First, as a general rule, one should not make medical decisions based upon small studies that are identified as pilot studies.  Doing so, one is likely to expose patients to risks that have not been justified by sufficient research.

Second, it is important to examine critically the outcome measures used in the study.  Specifically, it is necessary to look beyond the measures of statistical significance.  The statistics in this study look reasonably impressive, at first glance.  However, those numbers do not tell you what you really want to know.  Remember, statistical significance does not necessarily translate into clinical significance.  

So let's look at the numbers:

Sexual activity Baseline Sildenafil Placebo P a P b P c
Desire 4 ± 1.3 3.9 ± 0.5 4.1 ± 0.6 NS NS NS
Arousal 2.9 ± 1.2 3.7 ± 0.5 3.2 ± 0.3 <.01 NS <.001
Orgasm 2.8 ± 1.4 3.8 ± 0.8 3.1 ± 0.6 <.05 NS <.001
Enjoyment 3.5 ± 1.1 4 ± 0.5 3.7 ± 0.6 NS NS <.001
Satisfied by frequency 3 ± 1.1 3.2 ± 0.7 3.1 ± 0.4 NS NS NS
Frequency of intercourse 1.8 ± 1 2.3 ± 0.5 2.4 ± 0.6 NS <.05 <.05
Frequency of fantasies 2.1 ± 0.8 2.3 ± 0.4 2.2 ± 0.6 NS NS NS
Dyspareunia 2.3 ± 1.1 1.4 ± 0.8 2 ± 0.7 <.05 NS <.05

  • a Sildenafil vs. placebo.
  • b Placebo vs. baseline.
  • c Sildenafil vs. baseline.
Qualitative items were answered on a 5-point Likert scale, ranging from 1, not at all, to 5, a great deal. Quantitative items were answered as 0, never; 1, less than once a week; 2, once or twice a week; 3, several times a week; 4, once a day/sometimes twice; and 5, several times a day.

To be fair, the authors of the paper are cautious about interpreting the numbers.  They include all the appropriate cautions and limitations.  My concern is that a newspaper could easily pick up this story and print the high points, leading to a great deal of misinterpretation among the general public.  

When I get around to it, I'll put up another post with my interpretation of the numbers.  In the meantime medical students and interested readers are encouraged to look at the data and think about what conclusions may be justified by the numbers.

Depending on when I do get around to it, and when the new Seedlings go live, the follow-up post may be here, or it may be at http://www.scienceblogs.com/corpuscallosum (which is not up as of this writing).

Thursday, June 01, 2006

Climate Change Affects Blogs

Due to the unseasonably hot weather, Corpus Callosum will not be going to Seed tomorrow. The ScienceBlog meteoblogologists inform me that they expect the new Seedlings to sprout in 10 days or less. So all those good ideas I've been saving will have to wait.