Showing posts with label human diseases. Show all posts
Showing posts with label human diseases. Show all posts

Do Night Shifts Cause Breast Cancer?

Sunday, October 31, 2010 at 11:34 PM Bookmark and Share
According to this review article, the answer appears to lie somewhere between maybe and probably.  While there seems to be a correlation between the two, more research is needed to determine whether or not there is a causal link as other plausible reasons for the correlation haven't yet been ruled out.
...Shift work. Excess incidence of breast cancer has been observed consistently in studies of women with prolonged exposure to shift work involving exposure to light at night (Kolstad 2008; Stevens 2009). Research needs in this area include a) a better definition of what is meant by shift work and related exposure metrics; b) studies of markers of circadian disruption in non–day workers; c) better descriptions of controls and their exposure to light at night; and d) investigation of the effect of variations in expression of circadian genes on cancer in shift workers. An emerging area of interest is the relative toxicity of occupational chemical exposure depending on time of day of that exposure. The marked circadian variations in cell division and DNA repair during the daily cycle are controlled by the circadian genes (Haus and Smolensky 2006; Stevens et al. 2007). Therefore, non–day workers may have very different susceptibility to occupational exposures compared with day workers. Studies are also needed to determine if shift work is associated with other cancers, especially hormonally related cancers, and prostate cancer in particular. If further experimental and epidemiologic evidence confirms a causal association between exposure to light at night and breast cancer, it will be important to develop interventions to reduce the risk.

You can read more here. For details, see the article and relevant references.

Reference

  1. Ward EM, Schulte PA, Straif K, Hopf NB, Caldwell JC, et al. 2010 Research Recommendations for Selected IARC-Classified Agents. Environ Health Perspect 118(10): doi:10.1289/ehp.0901828

    Summary of Cancer Research Facts

    Friday, April 23, 2010 at 8:18 PM Bookmark and Share
    Over at the Respectful Insolence, Orac has shared a video produced by the American Association for Cancer Research which includes a wealth of information about the current state of cancer research.  You to read Orac's take on the video if you're interested in the topic (though do ignore his unappreciative take on the soundtrack!).


    What a remake of this video will look like 5, 10 or 15 years from now is anyone's guess -- but one thing is certain: it'll take a whole lot of money, manpower, technological innovation, and sound science if we're to continue to make progress in treating and preventing cancer.

    Behold... the human brain!

    Thursday, January 21, 2010 at 12:47 AM Bookmark and Share
    Tonight, while sharing a late night bowl of ice cream, my wife and I happened upon the fourth episode of the Brain Series by Charlie Rose. It pretty much poked all my science-dork buttons, so I of course had to run right over to the computer and put up a post telling you to watch the series - it's cool stuff!!

    You can see all available episodes of the series here. The discussions cover some interesting and important topics. I'm already excited for next episode on brain development and child learning.

    I haven't watched them all yet, but the series seems to touch on a variety of topics related to what our brains do and how they do it. The format is the usual scene: a table full of experts moderated by Charlie Rose. If anything, it's a great chance to hear a handful of experts discussing some of the latest insights into common brain disorders like autism/ASD, schizophrenia, and depression. There is also a fair bit of discussion related to brain development during the first few years of life, which should be of interest to parents.

    For more info, check the links above and your local PBS listings.

    Why use animals for scientific research?

    Sunday, November 15, 2009 at 5:37 PM Bookmark and Share
    [Hat tip to Dr. Isis]

    The American Physiological Society has a new FAQ up on using animals in scientific research (big emphasis on medical research).  If you've ever wondered...
    ... then hop on over to their website and have a look.

    Want to learn more about H1N1 flu, seaonal flu, vaccines, and who's most at risk?

    Tuesday, October 20, 2009 at 5:32 PM Bookmark and Share
    Today I caught part of a radio broadcast of a special edition of Second Opinion: H1N1 Special Edition. From what little I heard, it sounds like a fantastic discussion - one I hope you'll find the time to watch in it's entirety.

    Autism & Vaccines Revisted (... again)

    Tuesday, June 30, 2009 at 12:39 PM Bookmark and Share
    Massimo Pigliucci's has a nice post on his blog Rationally Speaking, summarizing a recent eSkeptic article entitled "Vaccines & Autism: A Deadly Manufactroversy." It's a nice read for those unfamiliar with the history of the widespread fear that vaccines are the cause of autism, and the consequences of that belief.

    In case you're wondering "Why all the fuss about the 'vaccines cause autism' scare?" I think the issue warrants attention for at least two reason: First, as countless individuals and organizations have made abundantly clear, we need vaccines to prevent the death and life-long suffering caused by preventable infectious diseases, particularly among children. Second, we need to focus on uncovering the real story behind autism so that we can more effectively treat and prevent autism spectrum disorders.


    Quinn, a boy with autism, and the line of toys he made before falling asleep.
    More about Quinn at: http://www.youtube.com/watch?v=G7kHSOgauhg



    A boy with a rash indicative of rubella (German measles)
    (click and search the CDC images for "10146" for details).
    Rubella during pregnancy can cause severe birth defects.


    To vaccinate, or not to vaccinate... is that the question?

    Monday, February 23, 2009 at 10:22 AM Bookmark and Share
    A friend of mine posted a link to this video today, which I thought deserved some critical commentary. Before I get into it, click below to watch the clip. Even better click here to watch it in another window - I'm sure you'll want to go back and forth and review some of the video segments as you read on.


    Lets start with Katie Couric's opening line in the piece, the rest of which is done by CBS's Sharyl Attkisson (whose strengths are more in matters of money and not medicine):
    For years now parents have wondered if vaccines are linked to conditions like autism and ADD. Government officials and some scientists say there is no connection, and they are often backed by independent experts. But just how independent are they?
    The first sentence implies those rightfully concerned parents haven't found any good answers, which is hardly the case. Plenty of answers can be found through one's local medical community, on the web at places like the National Network for Immunization Information, the U.S. Centers for Disease Control and Prevention, and so on. The claim that vaccinations cause autism and ADD have been investigated repeatedly by the scientific community and all the evidence suggests that vaccination won't give someone autism, ADD or the like - which is good news!

    Taking those findings more skeptically, they suggest that even if vaccines were capable of causing autism or ADD, the odds of it happening to any particular individual are vanishingly small. That is, you are much more likely to be killed in some kind of accident in the months after getting the shots - and much less likely to develop autism or ADD.

    The second part of this opening line is the real reason this clip caught my attention. The rather harmless sounding sentence calls into question the validity of all the work that has been done to understand the safety and risks associated with vaccines - by literally thousands of skilled people trained in using state of the art tools and methods to answer these kinds of questions - all cast into doubt by whether or not some organizations and individuals truly making independent claims from what the drug companies might say.

    To give you a more clearly dubious yet analogous statement, this is like saying that if you walked into a car dealership - having done your homework and concluded that a Honda Civic was the perfect car for you - you should suddenly become overwhelmed with doubt about your decision upon hearing the clearly biased salesmen tell you to go with the Civic. Whether or not some (in this case, 3) individuals and organizations have a bias in favor of an otherwise good idea does not invalidate all of the other evidence supporting the notion that it really is a good idea!

    The clip then goes on to point out financial ties between drug companies and three entities that one would expect to be "independent" from the likes of Merck and Wyeth: The American Academy of Pediatrics, Every Child by Two, and outspoken pediatrician Dr. Paul Offit, M.D.

    I must mention that Dr. Offit would otherwise be someone concerned parents would absolutely adore, were they made aware of his dedication to preventing childhood diseases, his work in doing just that, and his books to help inform the public on these matters. Instead, Sharyl Attkisson further vilifies him with remarks like "he has gone so far to say that babies can theoretically tolerate '... 10,000 vaccines at once.' " (This statement is a testament to the amazing capacity of the human immune system to fend of pathogens, by the way - not some expressed desire make pincushins of infants!)

    So what of their examples? Questionable or not, the consequences of any bias are blown way out of proportion here - although clearly some of these associations are to be frowned upon. AAP received $342K from Wyeth ("for a community grant program"), $433K from Merck (the same year their HPV vaccine was introduced), and unnamed funds from "another top donor, sanofi aventis." Each Child by 2 admits taking money, claiming no conflict of interest. However, their former treasurers - and the word "former" was absent from the script, but shows up in the visuals - included an official from Wyeth and one "paid advisor to big pharmaceutical clients" (which might sound bad, but without knowing the nature of the advising its hard to pass a quick judgment).

    We could go on and on, for example the statement that
    Today's immunization schedule calls for kids to get 55 doses of vaccines by age 6. Ideally it makes for a healthier society.
    "Ideally?" How about "clearly" or maybe "demonstrably"? Immunizations as part of overall improved health care do make for a healthier society than without them. If you need some evidence of this fact, consider the last time someone in your neighborhood died from or became paralyzed by polio. Even better evidence is readily available if you look for it, such as in this article, for example.

    Overall, I hope you can see how a little bit of critical thought on this piece turns up a lot of other issues that are probably more worthwhile to think about than how much money Merck gave the APP for a community grant program. Before you go, watch the piece again and let me know what you think!

    Finally, I'll end with a teaser for an upcoming post where I'll come back to this thread and discuss a few other question from this clip. These come from the way that Dr. Paul Offit was dubbed a "vaccine industry insider" (the implication here is of course, not positive) because his Merck-funded position at Children's Hospital, and the nature of his work in trying to prevent childhood diseases.

    It begs the question: What role should industrial/commercial/any scientists play in promoting products or information that by all measures will benefit society (in this case, that save lives)? When does "independent" trump "expert"?

    HIV: Modeling the experiment & the problem of evolution

    Wednesday, February 11, 2009 at 8:22 PM Bookmark and Share
    I just noticed a small article in the ScienceNOW Daily News on using microbicide gels to decrease the risk of contracting HIV. Give it a read!

    So why did this article (and this more detailed information from the NIH) catch my attention?

    Right now, as I type this, over 9,400 women in Africa are participating in a second, even larger clinical trial - the subject of some other interesting research I'll get into below. The results of that study will in large part determine whether or not this product makes it to market. Being my usual critical self, I immediately have two questions come to mind: "Will it be effective?" and "Is it safe?"

    This first question will get a strong answer via this study - after all, 'effective' is relatively straight forward thing to describe and measure. But what do we mean by "safe"?? This brings me to the other big reason this article grabbed my attention: Dr. Sally Blower.

    This past fall I had the pleasure of meeting Dr. Sally Blower, a mathematical biologist at UCLA, while I was visiting Ohio State's Mathematical Biosciences Institute during a workshop. She presented some of her research taking a critical look at the second study mentioned in the ScienceNOW article. Her technical paper on the matter can be found on her website.

    To briefly summarize the work she presented, she and her colleagues were interested in addressing the possible risk of drug resistant strains arising from the use of these microbicide gels. HIV has a relatively high mutation rate (leading to lots of genetic variation in a viral population) and anyone already infected with HIV who is exposed to anti-retroviral drugs (ARVs) could unknowingly be facilitating natural selection on the virus, leading to drug resistant strains of HIV. Unfortunately, this is a very real problem in the fight against HIV/AIDS, and to let a high-risk product pass clinical testing could come at a price in the long run.

    So to understand how well the experiment could assess this risk, as well as the efficiency of the microbicide gels as a means of protection against HIV infection, she and her colleagues created a computer model of the experiment. They began by simulating a population of women and men in which HIV was being transmitted.

    As the omniscient creators of this virtual world, they were able to include and manipulate many key factors in the transmission process, including other means of protection (e.g. condoms), the efficacy of the gels, and so on. They were able to "parameterize [the] transmission model using epidemiological, clinical, and behavioral data to predict the consequences of widescale usage of high-risk microbicides" in the population. They then collected data from a number of simulations, following the same type of protocol as the real study, which they could then compare to the actual transmission process in the simulated population.

    This clever use of mechanistic models and real world data accomplished two things. First, the computer model allowed them to assess the limitations of the real world experimental protocol, which helps researchers in their interpretation of the real-world experimental results. Second, because they were free to vary the model parameters and run the simulated experiment repeatedly, they could explore the simulated transmission process under different scenarios and describe how the factors included in the model contribute to the eventual outcome.

    So did we learn anything from all of this? Among their results, they found that the "planned trial designs could mask resistance risks and therefore enable high-risk microbicides to pass clinical testing" - unfortunate news. On the other hand, their findings suggest that "even if ARV-based microbicides are high-risk and only moderately efficacious, they could reduce HIV incidence."

    I can't say what the future holds for these microbicide gels, although I certainly hope they prove to be another means to battle against HIV worldwide. If you'd like more information on HIV/AIDS, check out the 2008 report on the global AIDS epidemic (I'd recommend browsing the "Media kit") from the United Nations Programme on HIV/AIDS.