Teenage milk consumption linked to acne

[KurtNYC]

According to studies conducted by the Department of Nutrition at Harvard School of Public Health, intake of milk and dairy products correlated with an increased incidence of acne in high school girls.

We found a positive association with acne for intake of total milk and skim milk. We hypothesize that the association with milk may be because of the presence of hormones and bioactive molecules in milk.

http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=15692464

[mom cat]

1. Got zits?

[liontamer]

2. and a lot of people are lactose intolerant and it shows up in their skin

first :shrug: I think they're overreaching on this one.

[Phx_Dem]

3. more junk science.

[ThomCat]

4. How so?

Can you site something wrong with their methodology?

[Phx_Dem]

6. what they did is an "archival study"

nothing was manipulated (you know like an independent variable). As such, the "samples" were not random or randomized. I could sit down and do a regression analysis between milk consumption and juvenile delinquency and find a very strong positive correlation, the results would be just as meaningless as this "study".

The only point in doing research like this is to develop a hypothesis that could be tested using a real/quasi experimental model.

[KurtNYC]

13. Wrong - you don't need a controlled experiment to reach these

conclusions or similar ones.

If someone's batting average is .317 then, by your assertions, it would be unscientific of me to conclude that they were successful in 31.7% of their at-bats. You're wrong; that is what science is.

[Phx_Dem]

16. Well if all you want to do is generate a hypothesis OK

but it proves nothing. BTW, I wonder how the researchers explain that they did not find statistically significant results for whole/2% milk, only the result for skim milk is sig. Maybe a whole bunch of confounding variables?

edit: to get technical with you, the study lacks construct validity.

[KurtNYC]

19. Hypothesis my butt - 122,000 subjects

higher diary consumption = higher incidence of acne. The correlation is established, peer-reviewed and confirmed.

To identify the exact mechanism, other studies would need to be done. Controlled studies if you like. But on correlation there is no doubt.

[Phx_Dem]

21. This milk study used 47,335 of the 122K

but that is basically beside the point, it does not matter how many subjects they used, their methodology is weak.

"higher diary consumption = higher incidence of acne. The correlation is established, peer-reviewed and confirmed."

You need to understand what construct validity is and then you will know why your statement is wrong.

"Example of construct validation procedure. Suppose measure X correlates .50 with Y, the amount of palmar sweating induced when we tell a student that he has failed a Psychology I exam. Predictive validity of X for Y is adequately described by the coefficient, and a statement of the experimental and sampling conditions. If someone were to ask, "Isn't there perhaps another way to interpret this correlation?" or "What other kinds of evidence can you bring to support your interpretation?", we would hardly understand what he was asking because no interpretation has been made. These questions become relevant when the correlation is advanced as evidence that "test X measures anxiety proneness." Alternative interpretations are possible; e.g., perhaps the test measures "academic aspiration," in which case we will expect different results if we induce palmar sweating by economic threat. It is then reasonable to inquire about other kinds of evidence.

Add these facts from further studies: Test X correlates .45 with fraternity brothers' ratings on "tenseness." Test X correlates .55 with amount of intellectual inefficiency induced by painful electric shock, and .68 with the Taylor Anxiety scale. Mean X score decreases among four diagnosed groups in this order: anxiety state, reactive depression, "normal," and psychopathic personality. And palmar sweat under threat of failure in Psychology I correlates .60 with threat of failure in mathematics. Negative results eliminate competing explanations of the X score; thus, findings of negligible correlations between X and social class, vocational aim, and value-orientation make it fairly safe to reject the suggestion that X measures "academic aspiration." We can have substantial confidence that X does measure anxiety proneness if the current theory of anxiety can embrace the variates which yield positive correlations, and does not predict correlations where we found none."

http://psychclassics.yorku.ca/Cronbach/construct.htm

[KurtNYC]

22. That pertains to the design of psychology studies which

are far trickier than biology. In biology, for instance one can do an autopsy and (usually) see exactly what killed an organism; psychology is seldom as clear cut.

Biology is far more mechanical. There is often an observable, easily testable, cause associated with an observed effect. For instance in biology we could know how much arsenic it takes to commit suicide versus in psychology, the question might by what caused the person to commit suicide by taking arsenic and that answer would involve many semi-subjective factors.

[Phx_Dem]

24. Inferential stats are used the same way in every field of study.

It does not matter what field is doing the research. Let me try to explain the main problem here. The researchers have made an assumption that milk consumption is related to acne problems, they then collected archival data and calculated regressions (or manova, doesn't matter).

Based on the type of analysis they used, causality can not be confirmed from the results, only that there may be a relationship.

As I pointed out in a post up-thread, their results are inconsistent as well:

whole milk: p = .57
low fat milk: p = .25
skim milk: p = .003

According to their own results, only skim milk is significantly related to acne, which makes no sense at all. What it really tells a person is that there are variables that are affecting the data which have not been accounted or controlled for.

[KurtNYC]

5. This is from the Harvard Nurse Study

which started in 1976 and uses input from over 122,000 registered nurses. It is the largest, longest study ever done and is the gold standard of nutrition research.

Here is another finding from the study:

Parkinsons Disease ("PD") probably linked to higher intake of dairy products in men

Intakes of calcium, vitamin D, and protein from other dietary or supplemental sources were not related to PD risk in men. Our results suggest that higher intake of dairy products may increase the risk of PD in men; however, this finding needs further evaluation, and the underlying active components need to be identified.

http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=12447934&dopt=Abstract

They are very careful about what they say conclusively. I note the difference between this conclusion and the one in the OP is that this link is probably but not conclusive enough for Harvard. The acne conclusion bares no such disclaimer.

[Phx_Dem]

9. Well at least the author "hedged" their bets.

I don't think research like this is competely useless, it can be an effective way to develop a hypothesis that can be tested using real experimental models. However, the problem is that studies like the milk one are reported to the media as proof, results etc. when that is not an accurate description.

My advanced stats prof. used to tell us that MDs do not receive adequate training with experimental methods and that is why they often mis-use stats. Think broccoli, salt intake, oatmeal, breast-feeding, all the conclusions made by the medical community were wrong because they did not bother to do actual experiments before releasing results.

[KurtNYC]

12. It isn't one author

and this wasn't shopped to MSM sensation mongers. This is analysis from the Harvard Nurse Study.

Your stats prof has no monopoly on statistical analysis. It is the media, not doctors, who don't understand science and delight in mis-representing the results of studies.

If a 30 year study conducted by Harvard and using 122,000 highly trained, highly motivated registered nurses and doctors, producing peer-reviewed analysis does not meet your threshold to rise above "junk science" please tell me what does.

[Phx_Dem]

15. the original reaseach may have been solid

but now they are just cherry picking data out of the data-set.

[Phx_Dem]

17. Link

The poor quality of much medical research is widely acknowledged, yet disturbingly the leaders of the medical profession seem only minimally concerned about the problem and make no apparent efforts to find a solution. Manufacturing industry has come to recognise, albeit gradually, that quality control needs to be built in from the start rather than the failures being discarded, and the same principles should inform medical research. The issue here is not one of statistics as such. Rather it is a more general failure to appreciate the basic principles underlying scientific research, coupled with the "publish or perish" climate.

As the system encourages poor research it is the system that should be changed. We need less research, better research, and research done for the right reasons. Abandoning using the number of publications as a measure of ability would be a start.

Douglas G. Altman
Head

Medical Statistics Laboratory
Imperial Cancer Research Fund
London WC2A 3PX

http://www.chiroweb.com/archives/12/13/06.html

[KurtNYC]

20. That is not referring to the Harvard Nurses' Health Study

The Nurses' Health Study, established in 1976 by Dr. Frank Speizer, and the Nurses' Health Study II, established in 1989 by Dr. Walter Willett, are among the largest prospective investigations into the risk factors for major chronic diseases in women. The studies have grown to include a team of clinicians, epidemiologists, and statisticians at the Channing Laboratory along with collaborating investigators and consultants in the surrounding medical community of the Harvard Medical School, Harvard School of Public Health, Brigham and Women's Hospital, Dana Farber Cancer Institute, Boston Children's Hospital, and Beth Israel Deaconess Medical Center.

http://www.channing.harvard.edu/nhs/

Again, this is among the most solid, well-funded, longest term, largest sample research ever done.

[Phx_Dem]

25. More links

"In July 2002, the national Women’s Health Initiative (WHI) terminated its randomized controlled trial of estrogen and progestin because the health risks of the regimen clearly outweighed the benefits. Its most startling finding--that HT increases the risk of heart disease--seemed to contradict the conclusions of several Nurses' Health Study (NHS) reports."

"Observational studies have been tremendously helpful in generating hypotheses. They are often on target, but in this case there’s a divergence, and we need to get a better understanding of why that is."

http://www.hsph.harvard.edu/review/review_fall_03/rshormones.html

"One can always find opposing studies on any issue, but health
recommendations should be drawn on the basis of the body of science as a
whole. However, scientists and researchers recognize that controlled,
prospective trials are the only way to establish a causal relationship.
Typically these are randomized, controlled trials, preferably
double-blinded. The Nurses' Health Study being cited is an observational
study and is inconclusive. Since observational studies do not control for
other factors that may influence the cause and effect under study, they
can never produce definitive results, nor can they negate evidence
produced from studies with stronger designs, e.g, randomized, controlled
trials. To date their have been 28 randomized, controlled trials with
calcium-rich foods or supplements, all positive."

"In addition to being an observational study, the Nurses' Health Study
is based on food diaries. Any study using food questionnaires should be
viewed with great caution," says Barbara Levine, Director of the Calcium
Information Center, The New York Hospital, Cornell University Medical
College. "This assessment tool is imperfect at best. We know people
can't recall food diaries accurately in the recent past, let alone in
years past."

http://www.foodcontamination.ca/fsnet/1999/3-1999/fs-03-03-99-01.txt

"In an editorial accompanying the study, Dr. Deborah Grady and Dr. Stephen B. Hulley of the University of California, San Francisco, suggested that the observed increased risk of stroke "could substantially decrease the overall benefit of hormone therapy" (Ann. Intern. Med. 133<12>:999-1001, 2000).

They added that although the data from the Nurses' Health Study appear to suggest that HRT reduces cardiovascular risk, HRT should not be used "for prevention of coronary disease until this practice is supported by evidence from randomized trials."

http://www.findarticles.com/p/articles/mi_m0BJI/is_3_31/ai_71632732

"A new study published in the June 22, 1995 issue of New England Journal of Medicine concludes that there is no association between silicone gel breast implants and autoimmune disease.

he study was initiated in 1992 by sending questionnaires to nurses who had been followed as part of a larger study since 1976. All the participants in the study were at least 46 years old. As the authors themselves admit, the study does not prove that silicone gel breast implants..."

http://www.newsrx.com/newsletters/Womens-Health-Weekly/1995-07-03/2383651WW.html

"But since then, attitudes have changed. For example, from the NIH:

Do not use estrogen plus progestin therapy to prevent heart disease. The new findings show that it doesn't work. In fact, the therapy increases the chance of a heart attack or stroke. And it increases the risk of breast cancer and blood clots.
The Nurses Health Study seems to have struck out on that one! The women who took HRT were apparently quite a bit different, on average, from those who didn't--even after "controlling" for background variables."

http://www.stat.columbia.edu/~cook/movabletype/archives/2005/01/could_propensit.html

"Because the Nurses and Health Professionals study is held to be the "gold standard" of nutrition research by some members of the media, the public is largely unaware of the important limitations in the study's design."

"The Nurses Study should contribute to ongoing scientific discourse," he added, "not replace it."

http://www.charitywire.com/charity10/00228.html

[sgxnk]

28. Phx_dem is SPOT ON

also note that much of the junk science comes from those with agendas

like that's a surprise

two of the biggest junk science proponents on the earth are PCRM and PETA

both of which regularly fund and selectively report on studies to try to prove that all animal products are bad for you

it is so absurdly transparent to anybody who spends any time reading studies

[Phx_Dem]

29. thanks, I was starting to think I was just talking to myself....

[shain from kane]

7. Soured on milk. So that's the beef. n/t

[MrPrax]

8. Drinking milk

usually plays havoc with your system anyway. Skin reactions? Sounds about right. The only real diary people should use is processed diary like cheese...milk isn't healthy, it's a market.

[shain from kane]

11. I've read somewhere that in the entire animal kingdom only human beings

drink milk into adolescence and beyond. Of course, we are talking about cow's milk, rather than mother's milk. It is considered a food product, included on the food pyramid, but it is still essentially milk. If during the process of evolution, we learned what plant and animal life was available for food purposes from watching other animals, as well as fellow human beings, at what point did we decide that milk would be good for us throughout our lifetime?

[MrPrax]

14. Yup...

Milk in North America is tied to the post-war milk production -- it was another oversupply problem and so they 'invented' as a part of the food pyramid.

Your right -- mammals stop weaning and the vast vast majority of the world's humans NEVER drink raw milk in any form -- but in North America we are arrogant and want to believe marketing. There is some enyzme that we have as a baby that helps process the fat sludge to take out the stuff we need as newborns -- but we lose that enyzme at an early age...so basically it's just fatty mucus slicking out the intestines and inhibiting the processing of other things in food, we do need.

I figure it's some form of consumer addiction, largely because, I could never figure out what exactly all those people who are very concerned about their health and vegetarians, nonetheless, have a real problem breaking the 'milk' habit and simply substitute the 'ritual' with replacements like soya? Why would you mix soya beans and coffee beans together? It's tastes terrible and ruins the flavor of both -- might as well just have the coffee.

[Odin2005]

27. Wrong, milk has been imporants in many cow-raising cultures for 1000's...

...of years. Some Northern European populations have vurtually 100% tolerance to lactose because of this.

[uberblonde]

10. I suspect there's a difference...

Between the chemical-laden milk most of us drink and organic milk, as far as these results.

[AirmensMom]

23. I was thinking the same thing.

Oh, and welcome to DU! :hi:

[gula]

18. Strangely enough I drank milk all my life and never had acne,

neither did my siblings or any other farmer's kids I knew.

Could it be that the milk was fresh from our "vegetarian" cows? No manipulation, no additives, etc.

[eppur_se_muova]

26. So I should stop drinking teenage milk?

:shrug: and go for older women?

[Warpy]

30. I was seriously lactose intolerant from about the age of six

and my mother was convinced I was going to an early grave if she didn't force milk into me.

Some days I was lucky and she'd leave the room long enough for me to pour it down the sink. Other times, I had to drink the horrible stuff and have diarrhea at school.

By the time I was a teenager, I was much better at manipulating the situation, so the milk went down the drain more often than not.

Nice to know she was giving me zits along with intestinal hell.

Milk is horrible stuff. I haven't gone near it since I left home. The only dairy I'll eat is rare yogurt and a dish of ice cream if I ever get constipated.

[HysteryDiagnosis]

31. Udderly ridiculous. Pass the clearasil. n/t