Popular Joint Pain Supplements Don't Work

The popular joint-pain supplements glucosamine and chondroitin are ineffective in reducing knee or hip pain due to osteoarthritis, according to a recent report in the British Medical Journal. The latest meta-analysis reviewed 10 previous large, randomized, controlled studies. The authors conclude that the two supplements have no effect on either patient perception of joint pain or minimum width of joint space (a clinical measure of improvement) when compared to a placebo.

Glucosamine and chondroitin are among the most popular over-the-counter supplements, with annual sales of nearly $2 billion per year. Some people swear by the two supplements because they genuinely do feel better when taking them, and I sincerely believe they’re telling the truth. But the improvements could be due to the well-known placebo effect, or to the fact that in some patients, joint pain declines over time due to natural healing processes. Anecdotal evidence can’t be generalized to a larger population.

The authors of the study see no harm in patients continuing to take the supplements if it makes them feel better. They say that neither supplement does any harm (except to lighten your wallet a little).

Texting and Fatal Driving Accidents

Text messages sent per month from hand-held phones increased more than 15-fold from 2002 to 2008. Over the same years the percentage of fatalities in which distracted driving was listed as a possible contributing factor increased from about 12% to nearly 16%.

Based on these data, the authors of a recent report speculate that texting while driving may have contributed to 16,000 additional driving fatalities between 2001 and 2007. The claim was reported in the Los Angeles Times and other papers, but is it true?

There are several problems with this report. First, the authors defined a fatality as caused by driver distraction whenever a distraction was merely listed as present. Other factors such as equipment failure, alcohol, or driver age were not considered. Second, distractions are anything that takes the driver’s attention away from driving, including texting or talking on a hand-held phone, reading an on-board navigation system (also increasingly popular these days), reaching for something, eating, drinking, putting on makeup, etc. Searching for street signs or rubbernecking another accident are also distractions. None of these were factored out in this study.

All the report really shows is that text-messaging volumes (in and out of cars) and the number of fatal accidents due to all distractions are both going up. The authors call it a correlation, but so what? A correlation does not prove causation. I’m reminded of the example presented by my thesis advisor years ago of the tight correlation between the rise in the number of telephones in the U.S. and the decline in the incidence of tuberculosis. Do telephones prevent tuberculosis? Hardly.

Is texting while driving a problem? Probably yes. Does this paper convince me that texting while driving has caused 16,000 additional fatalities? Sadly, no.

Biomechanics

We don't get a lot of biomechanics talks here so I'll highlight this one. There was a nice article about this work at ScienceDaily recently.

Swimming and filtration in the ocean by jet-propelled salps
Dr. Kelly R. Sutherland
Postdoctoral Scholar in Bioengineering, California Institute of Technology

MECHANICAL ENGINEERING SEMINAR
Engineering Sciences Building, ESB 1001
Thursday, October 4th, 4.00 p.m.

Salps are barrel-shaped marine organisms that are common in the open ocean and swim using a pulsed jet.  Among salp species, there are a variety of body shapes and swimming styles that correspond to differences in ecological function.  Dye visualization via bluewater SCUBA techniques and laboratory Digital Particle Image Velocimetry (DPIV) were used to describe jet wake structure and swimming performance variables including thrust, drag and propulsive efficiency among three salp species (Pegea confoederata, Weelia (Salpa) cylindrica, Cyclosalpa sp.).  Locomotion by each species was achieved using vortex ring ring propulsion.   Different combinations of swimming speed and hydrodynamic efficiency were observed and can be considered in light of metabolic constraints and ecological roles.  Though nature does not strive for optimality, this work shows the value of a comparative approach for understanding how underlying structure and mechanism influence performance.     

During swimming, the same fluid that propels the salp forward also contains food particles, which are captured on a mucous mesh as fluid passes through the mostly hollow body.  Though salps are centimeters in length and swim at speeds of ~1-10 cm s-1, filtration occurs on a fine, mucous mesh (fiber diameter ~0.1 μm) at low velocity (1.6 cm s−1) and is thus a low Reynolds number (Re ~10−3) process.  A model of particle capture efficiency by a rectangular mesh was used to estimate particle capture rates on the salp filtering mesh based on realistic oceanic particle concentrations.  Particle feeding experiments using 0.5, 1 and 3 µm fluorescent polystyrene microspheres were then performed to test the theoretical model.  Results from both the model and from experiments showed that smaller particles are captured at considerably higher rates than larger particles.  Though particles smaller than mesh openings (1.4 µm) are expected to supply substantially less carbon than larger particles, they can still completely satisfy salp energetic needs.  By removing different sized particles with nonuniform efficiency and packaging them into fast-sinking fecal pellets, salps have the potential to structure oceanic particle size spectra.

Labwork opportunity

Tom Smith, a grad student in  in Cherie Brigg's lab is looking for a couple students to help him sort and ID insects and algae, etc. His project involves describing Sierra Nevada alpine lake communities and their response to extinction of endemic frogs.
Contact Tom directly if you are interested.

From Silent Spring to Silent Night

Advance notice on this one. Tyrone is an excellent speaker and his work is very interesting. As a side note, Tyrone works with a huge number of undergraduates and if he was at UCSB I'm sure he'd be a favorite with CCS students.

Tyrone Hayes,  Professor, UC Berkeley

"From Silent Spring to Silent Night: What happens if our canary stops singing?"
Hosted by Bren Professor Patricia Holden as part of the Seminar in Ecotoxicology

Friday, Oct. 8, 2010
11:00 a.m. - 12:00 p.m.
Bren Hall 1414 

Abstract

The herbicide atrazine is a potent endocrine disrupter that chemically castrates and feminizes exposed male amphibians. Further, when combined with other pesticides, exposure results in a hormonal stress response that leads to retarded growth and development, and immuno-suppression. The immuno-suppression results in increased disease rates and mortality. Though many factors likely contribute to amphibian declines, pesticides likely play an important role even in populations that appear to decline for other reasons, such as disease. Pesticides like atrazine are ubiquitous, persistent contaminants. Effects of exposure have been shown in every vertebrate class examined (fish, amphibians, reptiles, and mammals) via common mechanisms. These observations demonstrate the critical impact that pesticides have on environmental health. Furthermore, reproductive cancers and birth defects associated with exposure to many of these same chemicals (e.g. atrazine) via identical mechanisms demonstrate that the impact on environmental health is an indicator of a negative impact on public health. Many of these mechanisms are being revealed only now in the scientific literature and agencies (such as the Environmental Protection Agency) are ill-equipped to deal with this emergent science and translate it efficiently into health-protective policies. Given the importance of this science and relevance to public health, there is a strong need to translate this information and provide public access to this knowledge. In particular, minority populations, more likely to be exposed to these chemicals, more likely to suffer health effects associated with exposure, less likely to have access to adequate health care and less likely to have access to this information, need to be informed. It is especially incumbent upon research scientists to make accurate accounts of these data available when industry and agency representatives (e.g. the EPA) provide inaccurate information to the public.

CCS distinguished lecturer

The first CCS Distinguished Lecturer for 2010 - 2011 will be Mary Roach, author of "Stiff", "Spook" and "Bonk' and now "Packing for Mars".

This will be of interest to CCS Literature and Science students, as Mary writes about science, particularly biology  - "Stiff" looks into "the curious lives of human cadavers",  "Spook" into claims of the afterlife and "Bonk"  into the somewhat whackier aspects of the physiology of sex (see reviews).

She will be available to talk with CCS students in the Gallery on Monday October 4th at 4:00 PM and will be giving an arts & lectures address in Campbell Hall at 8:00 that evening. (General $10, Students $6)

This is an opportunity to converse with a successful and off-the-beaten track author who is noted for a combination of insight & humor.  Be sure to visit her website  and read her biography.