Study Links Breast Cancer to Antibiotics Use - WaPo

[TacticalPeek]

Study Links Breast Cancer to Antibiotics Use

By Rob Stein
Washington Post Staff Writer
Monday, February 16, 2004; 2:27 PM

Antibiotic use is associated with an increased risk for breast cancer, a new study
has found, raising the possibility that women who take the widely used medicines
are prone to one of the most feared malignancies.

The first-of-its-kind study of
more than 10,000 Washington
state women concluded that
women who used the most
antibiotics had double the
chances of being struck by
breast cancer, that the
association was consistent for
all forms of antibiotics and that
the risk went up with the
number of prescriptions, a
powerful indication that the link
was real.

A variety of experts quickly
cautioned, however, that the findings should not stop women from taking the often
life-saving drugs when they need them to treat infections. There could be other
explanations for the association, and much more research is needed before
scientists understood what the surprising results mean, they said.

more

http://www.washingtonpost.com/wp-dyn/articles/A45831-2004Feb16.html

[Snow]

1. Whoa! Fascinating!

and a first glance at the article reveals that these are reputable people who've done the study. I'll have to go read the original paper. I'll let you know more. You guys do realize there's a small core of people who think breast cancer has an infectious component, and that something that happens when you get infections is that you tend to get treated? So it might be the bug, not the treatment.

on edit: went to look at the journal, and they haven't released this issue for us lowly scientists, physicians and subscribers in general yet - just spilled the article to the news media. Now frontline docs will have to deal with freaked women calling up & asking about this, & they won't have had a chance to read the article because they don't have their copy yet. I hate it when scientific/medical journals do that!

[Emillereid]

2. Hi Snow --

Or it might have something to with antibiotics tendency to kill off 'beneficial flora' in the gut thus undermining the immune system as well as optimum digestion/absorption. There seems to be a a dose response which is impressive.

Re: bugs as the underlying cause of much of today's maladies. There was an interesting piece in the Atlantic monthly a while back about this. It prompted me to do some research and a paper concerning the possible connection between the borna disease virus and depression and schizophrenia -- pretty compelling stuff. Also there's been some speculation that bugs might even be a partial explanation for our obesity epidemic.

[Snow]

6. Hey, Liz - not to threadjack, but

for schizophrenia there's very solid evidence for 2nd trimester of pregnancy maternal viral infections being a very heavy contribution to the cause - might even be a necessary cause.

For the rest of yuo folks, when epidemiologists talk about 'cause', we're never talking about 'flip the switch, the light goes on' type cause. All diseases have many components to their cause - in fact I can't think of any disease where the necessary cause is also a sufficient cause. Rabies, maybe? Anyway, disease causation is complicated - that's why the research is fun! (I sure don't do it because it makes me rich & famous).

[Emillereid]

7. Got that right -- no riches in research -- but lots of brain

stimulation -- should save us from alzheimers, I hope. At least if a bug don't get us first. I know about the pregnancy connection -- some vital brain growth taking place that seems to get messed up about that time. Fellow at UCLA been documenting the prenatal brain abnormality and schizophrenia for years. The borna disease virus is implicated particularly. There's a whole institute devoted to its study in Germany -- they sent me lots of materials and links to 'ongoing', not yet published stuff. The borna disease virus is the cause of the original 'mad horse disease' -- not unlike mad cow.

[kutastha]

20. A liver thing?

Perhaps it's not bug-related and is something to do with liver enzymes and the degradation of antibiotics and estrogen by common pathways. Over time, this could provide an imbalance in hormone levels.

[Snow]

23. Hmmm, that's a thought - the

infamous P-43 maybe?

[kutastha]

24. CYP1B1

metabolizes estrogen into the cancer-associated product 16alpha-hydroxyestrone. If antibiotics use that pathway, long term or high use of them could ramp up this p450's function.

edit: a little cleaning up

[treepig]

32. i did a research paper on the borna disease virus

round about 1999 - any startlingly new developments to share?

anyhow, the real reason that i'm posting is that you may be onto to something wrt to your hypothesis that antibiotics lead to cancer due to the kill off of beneficial flora in the gut.

specifically, bacteria in the gut produce Short Chain Fatty Acids (SCFAs), most noticeably butyrate, that have anti-cancer activity:

Proceedings of the Nutrition Society (2003), 62, 107–115 DOI:10.1079/PNS2002230
© The Authors 2003
CAB InternationalPNSProceedings of Nutrition Society (2003)© Nutrition Society 2003 62 PNS 230Short-chain fatty acidsE. A. Williams et al.107 115 9© Nutrition Society 2003
Anti-cancer effects of butyrate: use of micro-array technology to
investigate mechanisms

Epidemiological evidence suggests that a high intake of resistant starch and NSP protects against
colo-rectal cancer. The mechanisms underlying this protection are thought to be mediated by the
short-chain fatty acid butyrate, which is present in the colonic lumen in millimolar concentrations
as a result of bacterial fermentation of carbohydrates that have resisted digestion in the small
intestine. In vitro studies have shown that butyrate displays a host of chemo-preventative
properties including increased apoptosis, reduced proliferation, down regulation of angiogenesis, . . .


so far, it's not really clear if bacterial-generated butyrate is protective against cancers that are located away from the gutin humans(such as breast cancer in this case), but such a link may exist in animal models:


Nutr Cancer. 2000;36(2):217-23.
Dietary butyrate inhibits NMU-induced mammary cancer in rats.

Butyrate has been proposed as an antineoplastic agent, leading to the inhibition of tumorigenesis. The purpose of this study was to examine butyrate, supplied as tributyrin (Tbn) or as a natural component of anhydrous milk fat (AMF), on the development of nitrosomethylurea-induced mammary tumors in female Sprague-Dawley rats. Diets were 1) semipurified rodent diet (AIN-93) with high fat <20% sunflower seed oil (SSO), control>, 2) SSO diet with Tbn added at 1%, 3) SSO diet with Tbn added at 3%, and 4) 19% AMF with 1% SSO diet, which contained butyrate equivalent to the 1% Tbn diet. These diets were fed ad libitum from weaning at 21 days of age, and at 24 days of age each rat was injected with nitrosomethylurea (50 mg/kg body wt i.p.). At any one period, there was a relative risk increase of 88% (p < 0.05) that rats in the SSO diet group would develop a mammary tumor compared with those in the AMF diet group. The addition of 1% and 3% Tbn to SSO diets reduced the tumor incidence by 20% and 52%, respectively, in comparison to SSO alone (p < 0.05). There was a linear inverse relationship between Tbn concentration and rats developing a tumor. From 89 days to the end of the experiment, rats fed the diet containing 3% Tbn showed a significantly lower multiplicity of palpable tumors (50% less at Day 118, p < 0.05) than SSO-fed rats. These results indicate that although the AMF diet was effective, particularly early in reducing mammary tumorigenesis, the 3% Tbn diet produced a sustained reduction of tumor multiplicity relative to the control (SSO) group. An inhibitory influence of butyrate on mammary tumorigenesis against a background of high polyunsaturated fat diet has been demonstrated in this animal model of breast cancer.

[cosmicaug]

3. References.

Snow wrote:

You guys do realize there's a small core of people who think breast cancer has an infectious component,

Other than viral infections (and there are a handful that do have carcinogenic potential) do you have any references? I know of some who believe in an association of cancers with bacteria like organisms but they are rather kooky (to make an understatement). I'd like to know more about this school of thought which posits an infectious component to some breast cancers.

Snow wrote:

and that something that happens when you get infections is that you tend to get treated? So it might be the bug, not the treatment.

That immediately jumped to my mind also. Other things are possible too (and it looks like they explored at least some). For instance, there might be some unknown risk factor which produces immune depression resulting in both increased susceptibility to cancers and increased susceptibility to bacterial infections.

[Snow]

5. There's been some good work done in Adelaide....

but I don't remember details. I'll dig it up. It is regarded as fringy; standard thinking is that breast cancer is caused by female hormones. Never mind that the idea is well over a hundred years old and gotten us absolutely nowhere.

[Emillereid]

8. Not caused by hormones, Snow --

or every young woman, especially pregnant ones, would have breast cancer. Some breast cancers appear to feed on 'unopposed' estrogen. Hormone balance or lack thereof is (not enough progesterone to dampen the effects of estrogen proliferative tendencies) seem implicated. Read "Sex, Lies and Menopause" by Wiley, Taguchi and Formby (2003) for a thorough examination of the role hormones, real and man-made play in breast cancer. It recommends real, bio-identical hormone replacement in physiologic amounts to replicate the cyclical, rhythmic hormones of youth. Lots of compelling evidence that this kind of HRT might even be the ticket for women with breast cancer. BTW, I'm doing it myself.

[Snow]

9. But you see, that's conventional wisdom, and it dates waaay back..

if it's a cancer of female organs, then it must be caused by female hormones, and there is support - more nuns and other nulliparous women get breast cancer, early and frequent pregnancy is protective, things like exercise or soy intake that reduce endogenous hormones are protective - you see, there is something there, but it's weak, and it's all that most of the research talks about. So you don't gain any ground whatsoever by saying the hormones don't mean anything; it needs to be approached as an additional sort of thing. We used to think cervical cancer was hormonal, too.....

[Emillereid]

11. Not saying hormones don't mean anything -- they mean alot

Estrogen is just not 'causative' is the strict sense of the word. Hormonal balance is everything though -- if everything is working right pre-menopausal women (who usually don't get breast cancer) have a rhythmic, hormonal cycle of rising estradiol which when it peaks creates progesterone receptors and then rising progesterone which in turn peaks and creates estradiol receptors -- they are involved in a monthly dance. After menopause of course with no popped egg, not only is estradiol low, progesterone is usually lower. The body needs estrogen for thousands of reactions -- unfortunately the body often turns to fat cells that turn out a weaker form -- estrone. (Estrone is the estrogen that has been implicated in breast cancer and may be the hidden link with any association that breast cancer seems to have to obesity) The need for estrogen may be one of the reasons for the female middle age weight gain. The other source of progesterone is the adrenal glands. But generally not enough is made to 'oppose' even the little estrogen that a woman makes. The upshot is that during peri-menopause and after menopause, women's hormones are low, static and completely out of balance. Even low estrogen is still proliferative (a good thing generally speaking) but not dampened or refined by progesterone it is theorized to 'lead' to or feed certain cancer. There is some exciting work showing that progesterone works to stimulate apoptosis in breast cancer lines and a return to youthful hormonal balance using bio-identical stuff may be the real way to cheat mother nature.

BTW,Wiley et. al examine the problems involved with delayed pregnancy and lack of breast feeding with later breast cancer quite well.

[Snow]

12. Hmmm, interesting ideas....

could be a part of it, especially since breast cancer is principally a problem of older women (like 70's). Lotta people, including docs, don't realize this, and seem to have the idea that deadly breast cancers are zooming up in young women. Not true.

[Emillereid]

13. That's why it's so good to have epidemiologist on board!

When we LA Duers getting together anyway?

[Snow]

10. Here's a start:

this is a very mainline group
- snip -

Breast cancer, birth cohorts, and Epstein-Barr virus: methodological issues in exploring the "hygiene hypothesis" in relation to breast cancer, Hodgkin's disease, and stomach cancer.

Krieger N, Strong EF, Makosky C, Weuve J
Cancer Epidemiol Biomarkers Prev 2003 May 12:405-11


Abstract
To address methodological issues in exploring a variant of the "hygiene hypothesis" that posits delayed infection by Epstein-Barr virus contributes to rising rates of breast cancer and Hodgkin's disease, we examined birth cohort trends in the incidence of both cancers plus stomach cancer, building on previously reported year-of-diagnosis cross-sectional associations of age-standardized rates. Using published data from the United States Connecticut state cancer registry (1935-1998) for women for each cancer site, we obtained age-specific incidence rates by birth cohort (1870-1874 to 1970-1974), along with age-standardized incidence rates for selected calendar years (1935-1939, 1940-1944,., 1990-1994, 1995-1998). Clear secular trends in incidence rates, in the opposite direction, were evident for: (a) breast cancer and for Hodgkin's disease in young adults (increasing), and (b) stomach cancer (decreasing). Correlations between the incidence of breast cancer among women ages 50-54 and Hodgkin's disease among young adults (ages 20-24) were stronger for birth cohort (Pearson correlation, 0.85) than for cross-sectional analyses (Pearson correlation, 0.68). Stronger associations between the incidence of breast cancer and non-Hodgkin's disease were evident for birth cohort compared with cross-sectional analyses, findings consonant with (but not "proof" of) the hygiene hypothesis. One methodological implication is that tests of the hygiene hypothesis must take into account birth cohort effects and age at incidence of the outcomes under study;

- snip -
and here
- snip -
Lytic viral replication as a contributor to the detection of Epstein-Barr virus in breast cancer.
Huang J, Chen H, Hutt-Fletcher L, Ambinder RF, Hayward SD
J Virol 2003 Dec 77:13267-74


Abstract
Epstein-Barr virus (EBV) has an accepted association with the epithelial malignancy nasopharyngeal carcinoma and has also been reported in other more controversial carcinoma settings. Evaluation of EBV association with epithelial carcinomas such as breast cancer would benefit from a better understanding of the outcome of EBV infection of these cells. Cell-free preparations of a green fluorescent protein-expressing virus, BX1, were used to infect breast cancer cell lines, which were then examined for EBV gene expression and viral genome copy number. Reverse transcription-PCR analyses revealed that the cells supported a mixture of latency II and lytic EBV gene expression. Lytic Zta and BMRF1 protein expression was detected by immunohistochemistry, and DNA PCR analyses estimated an EBV copy number of 300 to 600 genomes per infected cell. Evidence for lytic EBV expression was also found in breast tissue, where reverse transcription-PCR analyses detected lytic Zta transcripts in 7 of 10 breast carcinoma tissues and 4 of 10 normal tissues from the same patients. Scattered cells immunoreactive for Zta protein were also detectable in breast carcinoma. Quantitative real-time PCR analysis of EBV-positive breast carcinoma tissues suggested that less than 0.1% of the cells contained viral genomes. We suggest that sporadic lytic EBV infection may contribute to PCR-based detection of EBV in traditionally nonvirally associated epithelial malignancies.

- snip
and this is from the hypothesis journal
- snip -
Human breast cancer and lymphomas may share a common aetiology involving Mouse Mammary Tumour Virus (MMTV)

M. Cotterchion, V. Nadalina and M. Sauerc

Abstract

Mouse Mammary Tumour Virus (MMTV) causes breast tumours in mice, and has been implicated in the aetiology of murine lymphomas. Several recent human studies have detected MMTV-env DNA sequences in 30–40% of tumours from breast cancer patients but in less than 4% of normal breast tissue. MMTV DNA has been detected in simultaneously diagnosed primary lymphoma and breast cancer tissue, suggesting MMTV may be involved in the aetiology of both breast cancer and lymphoma. We further hypothesize that if lymphoma and breast cancer are both associated with a common aetiologic virus then women with prior lymphoma may have an increased risk of breast cancer and vice versa. Despite the significant increase in the incidence of both lymphoma and breast cancer over the last few decades, their aetiologies are not well understood. Intriguing evidence to date suggests that the aetiology of a subgroup of human breast cancers and lymphomas may have viral involvement, and this warrants further investigation.
- snip -

That's probably enough and more for the moment - as you see, there're several lines of thought out there. Personally, I like Nancy Krieger's (the first paper) notion that breast cancer is another 'hygiene' disease, like paralytic polio or asthma (maybe). The hygiene hypothesis roughly states that if you get infections when you're very young, not much happens other than maybe a case of the runs, but if you get the same bug when you're older, due to being raised in a clean, hygienic environment, you get much worse outcomes. If it's a polio infection for instance, you might get paralyzed. And breast cancer might well be the same sort of deal - it fits in a lot of ways, attacking higher social classes in greater proportions, for instance.

[cosmicaug]

17. I was hoping for bacteria.

Yeah, Epstein Barr is one of those potentially carcinogenic viruses (isn't there some sarcoma which is also associated with it? --I can almost say the name). Then there'd be some retroviruses causing some leukemias (HTLV --IIRC called HTLV1 & HTLV2 where H.I.V. was originally put into this family as HTVL3 --or something like that-- by Robert Gallo), and, of course, the papilloma viruses being associated with cervical cancers, and hepatitis viruses being associated with liver cancers (IIRC) and I can't think of any others though I might have missed a few (and there certainly are others for non-human animals --the one abstract you quoted mentioning one I had never heard of).

But, since antibiotics were mentioned, I was hoping for bacterial associations. Of course, it's always possible that people are being erroneously treated with antibiotics for viral problems and that that alone could account for such an association with antibiotic use.

[Snow]

28. Not a sarcoma - Burkitt's Lymphoma -

- with EB virus as a cause - started the whole business of realizing that a cancer could have an infectious component to causation.

I think the bacterial thing is interesting, but viruses make more sense because they're intracellular parasites and have more opportunity to mess up the dna, rna. Bacteria maybe could do that too, as witness helicobacter's role in stomach and maybe pancreatic cancer, but that's a different way of doing the trick.

[cosmicaug]

31. That's it!

As soon as I thought of Burkitt, the second half came to me also.

Snow wrote:

I think the bacterial thing is interesting, but viruses make more sense because they're intracellular parasites and have more opportunity to mess up the dna, rna.

Of course viruses make more sense than bacteria for this. That's why it would be interesting if bacteria could also did this sort of thing on a regular basis (but I'm guessing they don't).

[damnraddem]

4. The cost-benefit favors necessary use of antibiotics; ...

but this is another reason to stop the abuse of antibiotics -- it not only threatens the viability of antibiotics, it also unnecessarily increases risks of breast cancer.

[TomNickell]

14. A lot of infections....

Presuming the anti-biotics were taken to treat infections, the top groups had a -lot- of infections.

There may be an underlying problem which results in the large number of infections.

[plaguepuppy]

15. Presuming the anti-biotics were taken to treat infections

That may not be a safe presumption - out in the real world a lot of antibiotics are used to treat viral respiratory infections that don't respond to antibiotics. But it is true that more antibiotic prescriptions probably correlate with more infections of some kind, which could make it a marker for low-grade immune dysfunction. Or maybe it's a marker for less competent doctors who have a lower threshold for giving unnecessary antibiotics... though I can't see how that would influence cancer risk.

[preciousdove]

16. Junk Sicence, again.

Healthy people do not need multiple antibiotic prescriptions and it is easier to get morphine right now than extended antibiotic treatment. (I deal everyday with people seeking help when Lyme Disease is not treated aggressively enough and recurs.) At an EICS conference in 1999 the point was made that in the US we have very poor care for the chronically ill.

The reason cancer thrives is a glitch in the immune system allowing damaged cells to multiply unchecked. A healthy immune system, specifically large killer cells (type B immune cells) eliminate most cancers before they become a problem. Things like Lyme, Aids, Depression, CFS, etc interfere or compromise the B Cells and allow cancer to thrive. I would say that the conclusion is just shooting the messenger. Our broken medical system is failing to heed the warnings that a person who needs antbiotics to stay active and "get well" probably needs to have whatever is causing the immune system problem addressed. That is not happening and until it happens to you you think that if you ask for help when you are constantly ill you will get it.

Antibiotics are inexpensive and relatively benign when compared to raging infection and some of the newer very expensive treatments like Copaxone and other T cell modifiers. Tetracyclene for $10 a month keeps me out of the nursing home. I can get Copaxone for $1200 a month with no problem but getting the tetracyclene can be next to impossible.

If you are healthy this is a no brainer don't take medicine you don't need but when it comes down to questions of disability and quality of life there are a lot of things to consider.

Reminds me of the computer study that said that 75% of all stairway accidents happen on the top or bottem step. The computer's solution was to eliminate those steps.

[Snow]

18. Healthy people don't need antibiotics? Because antibiotics are used to

treat illness, perhaps? That's what we call a tautology, my friend.

Be careful of throwing statement like "junk science" out there it tends to raise hackles. This, in my opinion, is well-done science, and I have a suspicion I may be better qualified to judge it than you. Would you describe exactly how this study is junk, other than the generalities you've offered? Speaking of junk science, CFS is by no means universally accepted as non-junk - in my opinion it may be valid, but it's always hazardous to define a disease entity by symptoms alone.

Also, a 'glitch' in the immune system, while picturesque, is not what I'd call high-level science. Our medical system is not so much broken, in fact it works pretty well; it's the delivery and payment system that's a mess. It sounds like you're extrapolating personal experience to a broad and unfounded generality. Don't do it, and don't throw terms like "junk science" around unless you're prepared to prove you know what you're talking about.

[preciousdove]

19. Can't debate this late but...

here is where my knowledge has come from. The articles that discussed and footnoted what I said in my original post are not online right now. (The Lyme Alliance needs a webmaster. Lyme sites are routinely hacked).

Medical abstracts on Lyme Disease and Cancer from "Lots of Links on Lyme Disease".
http://www.geocities.com/lymeart3/cancer-links.html

Medical abstracts on Lyme Disease and cancer from the Lymenet.org website.
http://www2.lymenet.org/domino/abstract.nsf/$$Search

[cosmicaug]

21. Just clicked on a link at random and it doesn't look informative.

Just clicked on a link on the second page at random and it doesn't look too informative.

The link I clicked was at http://www2.lymenet.org/domino/abstract.nsf/$ and labeled MEDLINE - squamous cell carcinoma AND Lyme disease - 3 on 29 Sep 00.

It kicked up three abstracts:

1: Sambri V, Basso F, Massaria F, Ardizzoni M, Cevenini R. Related Articles, Links
Adherence of Borrelia burgdorferi and Borrelia hermsii to mammalian cells in vitro.
New Microbiol. 1993 Jan;16(1):43-9.
PMID: 8469170
2: Georgilis K, Peacocke M, Klempner MS. Related Articles, Links
Fibroblasts protect the Lyme disease spirochete, Borrelia burgdorferi, from ceftriaxone in vitro.
J Infect Dis. 1992 Aug;166(2):440-4.
PMID: 1634816
3: Riechelmann H, Hauser R, Vogt A, Mann W. Related Articles, Links

Laryngorhinootologie. 1990 Feb;69(2):65-9. German.
PMID: 2322358

The first two appear to deal with the interaction of B. burgdorferi with human fibroblasts. The last study was, apparently, investigating the correlation of B. burgdorferi antibodies with facial paralysis, sudden hearing loss, vertigo, and lymphadenitis of the head and neck and was using patients with other conditions (some with squamous cell carcinomas) as a control.

When I see that sort of stuff (where Medline links are seemingly produced at random which don't show anything remotely like what is being potentially claimed) it makes me not want to look any further (like I'm not lazy enough as it is).

[preciousdove]

26. Hey I really do understand

about not wanting to wade through these studies. The site is a catalog of all available literature on Lyme. That page references Lyme and Cancer.

Unfortunately doctors don't like to plow through this stuff and rely on others to draw sometimes illogical conclusions for them. There is a huge debate about the corruption of the stuides by researchers willing to give the results the people paying for the studies want to hear as well as interference by the insurance industry by manipulating the CDC, NIH and FDA by funding researchers who do will give the results corporations are looking for in order to market some product or allow or disallow certain medicines or treatents. This is general not related to any one illness or healh problem.

Take your vitamins and try not to get sick until the corruption stops.

[Snow]

29. The problem is not the wading so much, as that

the list of studies on those sites are really pretty far out of date. I looked at the dates, flipped through a few of the abstracts, then decided to go look at pubmed and see what the latest thinking is. I recommend that to you, as well..

[Snow]

22. All right, try this -

go to this site:
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
and plug lyme cancer - or whatever you wish into the title. What I got was after a brief look, a listing of Lyme and other bugs associated with lymphomas, which makes sense since lymphoma is an immune system cancer, and some stuff about how adenomas can be concealed by Lyme, how MS can be missed because of Lyme. Okay, Lyme's a nasty disease, it causes something very like Reynaud's syndrome, and we don't understand autoimmune diseases very well. I fail to see how that follows either from the original post or the relation to your 'junk science' remark.

[preciousdove]

25. The conclusion of the topic study here is not logical

Antibiotic use does not cause cancer, but the neccessity of repeated antiboitic use can indicate that the infividual is at a much higher risk for cancer due to immune system disfunction or other underlying disease. Aids, Lyme, Depression etc. Those things do not usually kill outright but the spirochetes, the virus or lack of sufficent normal brain chemicals left unchecked causes a weakened immune system that allows cancer to flourish.

[Snow]

30. But the authors don't come to that conclusion -

all they say is that antibiotic use and breast cancer are associated. Association does not mean causation, although it can help. And while I still haven't been able to read the article (bloody journals who put out press releases before sending the journals to scientists!) those issues that you raise have surely occurred to the authors and there will be some discussion of it at least in the discussion section of the actual paper.

Just for the mental exercise, you might want to think about how you'd design a study to address the questions you raise. Bear in mind breast cancer is rare, so you'd probably want to use a case-control design, which compares a group of patients with disease to a group of controls who are disease-free but in all other ways similar to the patients, and see how the two groups differ on the question you're concerned about. How would you assess that difference, and how would you compare it? This assignment will be due a week before the end of the semester - ooops, just joking, professor reflexes... ;-)

[0007]

27. Very interesting!