Denise has admitted that her critique uses the raw data (which from what I understand you're not supposed to do in stats) from the china project monograph; that she did her own analysis of the data and it showed essentially the same trends as the raw data; but she did not publish this because she didn't want to 'inundate' her readers with stats jargon.
This is the direct quote from Doug's forum for posterity:
BTW, I did run more complex modeling/multiple regression analysis on the data and found the trends held true, and in fact were even more accentuated than using simpler linear models and stratification. I didn't publish these on my critique due to space and complexity (usually readers don't want to be inundated with a bunch of statistics jargon), but I'll start compiling the data for another post that statisticians and epidemiologists might take interest in. I'll see if _______ has suggestions for other analytical methods as well.
The China Project is an epidemiological study, and because of that, it can only produce hypotheses -- never proof. Seeing two variables correlate positively, like plant protein and disease, only means that they happen to increase hand-in-hand. It doesn't prove that one causes the other, although it also doesn't exclude that possibility. Sometimes, there's another underlying variable to blame.
My critique is only intended to reveal errors in Campbell's analysis of the original data. It doesn't vilify veganism, but it does show that animal products can't be blamed for cancer and disease based on the China Study data.
My suggestion is to look at the data but not let it be the sole dictator of your decisions. At the end of the day, your body's reactions to a particular diet are more important than the results of any study, no matter how large and renowned it is.
1) in spite of being impressed if Denise did everything in the critique on her own, according to Campbell the big flaw in her work is that she relies almost entirely univariate correlations (relations between two variables e.g. fat consumption and breast cancer) from the China Project data, which can be misleading when examining on their own since many other factors can come into play in such a huge pool of data. He suggests a better approach to working with this type and volume of data (which is way over my head lol), and had written about these issues on interpreting the data for the China Project book but it was not included due to space constraints.
2) he also states that the Tuoli (the ostensible moo juice chugging tribe) only ate astonishingly high quantity of animal products for the 3 days data was being collected because according to Campbell "they were essentially eating as if it were a feast to impress the survey team". they did NOT eat that way year round. Obviously then Campbell was not 'covering up' this information as was suggested.
3) He says he made clear in the book that the China Study does not constitute 'proof' that the vegan diet is the way to go nor do all correlations in the data match perfectly with the message of the book, but rather suggests people to come to their own conclusions and TRY the diet, because it actually WORKS in practice, no shortage of clinical and anecdotal evidence to show this.
4) He's really not promoting veganism or vegetarianism with the book (apparently he doesn't even use the word in the text) as he's being accused of, he's just telling us what the science says.
4) He's a busy guy and doesn't have time to respond to long (and improperly done) critiques like Denise's point by point.
nice summary - perfectly captured, IMHO. you know, when i first told my colleagues that i am vegan, the overwhelming response was positive. comments like, "you're going to live for such a long time," or "your biological age is probably much younger than your chronological age," or "no cancer for you!"
the "ivory tower" is pretty convinced that a plant-based diet, in general, is healthful in and of itself. and i think the general public is too. the momentum is great, and i'm feeling super optimistic about the future!
B, i'm copying campbell's text here just in case it ever disappears.
nice summary, btw.
I don’t have time to review every comment but did quickly scan the text. This analysis seems very impressive, especially given the writer’s young age with no training in nutritional science (see her web page).
She claims to have no biases–either for or against–but nonetheless liberally uses adjectives and cutesy expressions that leaves me wondering.
As far as her substantive comments are concerned, almost all are based on her citing univariate correlations in the China project that can easily mislead, especially if one of the two variables does not have a sufficient range, is too low to be useful and/or is known to be a very different level of exposure at the time of the survey than it would have been years before when disease was developing. There is a number of these univariate correlations in the China project (associations of 2 variables only) that do not fit the model (out of 8000, there would be) and most can be explained by one of these limitations.
A more appropriate method is to search for aggregate groups of data, as in the ‘affluent’ vs. ‘poverty’ disease groups, then examine whether there is any consistency within groups of biomarkers, as in considering various cholesterol fractions. This is rather like using metanalysis to obtain a better overview of possible associations. I actually had written material for our book, elaborating some of these issues but was told that I had already exceeded what is a resonable number of pages. There simply were not enough pages to go into the lengthy discussions that would have been required–and I had to drop what I had already written. This book was not meant to be an exhaustive scientific treatise. It was meant for the public, while including about as much scientific data and discussion that the average reader would tolerate.
She also makes big issues out of some matters that we had no intent to include because we knew well certain limitations with the data. For example, only 3 counties (of the 65) consumed dairy and the kind of dairy consumed (much of it very hard sun-dried cheese) was much different from dairy in the West. It makes no sense to do that kind of analysis and we did none, both because of the limited number of sample points and because we discovered after the project was completed that meat consumption for one of the counties, Tuoli, was clearly not accurate on the 3 days that the data were being collected. On those days, they were essentially eating as if it were a feast to impress the survey team but on the question of frequency of consumption over the course of a year, it was very different. Still, the reviewer makes a big issue of our not including the data for this county as if I were being devious.
In short, she has done what she claims that should not be done–focusing on narrowly defined data rather than searching for overarching messages, focusing on the trees instead of the forest.
I very carefully stated in the book that there are some correlations that are not consistent with the message and, knowing this, I suggested to the reader that he/she need not accept what is said in the book. In this very complex business it is possible to focus on the details and make widely divergent interpretations but, in so doing, miss the much more important general message. In the final analysis, I simply asked the reader to try it and see for themselves. And the results that people have achieved have been truly overwhelming.
One final note: she repeatedly uses the ‘V’ words (vegan, vegetarian) in a way that disingenuously suggests that this was my main motive. I am not aware that I used either of these words in the book, not once. I wanted to focus on the science, not on these ideologies.
I find it very puzzling that someone with virtually no training in this science can do such a lengthy and detailed analysis in their supposedly spare time. I know how agricultural lobbying organizations do it–like the Weston A Price Foundation with many chapters around the country and untold amounts of financial resources. Someone takes the lead in doing a draft of an article, then has access to a large number of commentators to check out the details, technical and literal, of the drafts as they are produced.
I have no proof, of course, whether this young girl is anything other than who she says she is, but I find it very difficult to accept her statement that this was her innocent and objective reasoning, and hers alone. If she did this alone, based on her personal experiences from age 7 (as she describes it), I am more than impressed. But she suffers one major flaw that seeps into her entire analysis by focusing on the selection of univariate correlations to make her arguments (univariate correlations in a study like this means, for example, comparing 2 variables–like dietary fat and breast cancer–within a very large database where there will undoubtedly be many factors that could incorrectly negate or enhance a possible correlation). She acknowledges this problem in several places but still turns around and displays data sets of univariate correlations. One further flaw, just like the Weston Price enthusiasts, is her assumption that it was the China project itself, almost standing alone, that determined my conclusions for the book (it was only one chapter!). She, and others like her, ignore much of the rest of the book. Can any other diet match the findings of Drs. Esslestyn, Ornish and McDougall, who were interviewed for our book (and now an increasing of other physicians have done with their patients)? No diet or any other medical strategy comes close to the benefits that can be achieved with a whole foods, plant based diet.
I also know that critics like her would like nothing better than to get me to spend all my time answering detailed questions, but I simply will not do this. As we said in our book, no one needs to accept at face value what I say. Rather, as we said in the book, "Try it" and the results will be what they are. So far, the reports of positive benefits have been nothing less than overwhelming.
I hope this helps, although it was written in haste.