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Research

Dietary protein sources in early adulthood and breast cancer incidence: prospective cohort study

BMJ 2014; 348 doi: https://doi.org/10.1136/bmj.g3437 (Published 10 June 2014) Cite this as: BMJ 2014;348:g3437

Re: Dietary protein sources in early adulthood and breast cancer incidence: prospective cohort study

Confucius advised that:


Learning without thought is labour lost;
Thought without learning is perilous.


Had Confucius lived into the present day he may have come to consider that:


  • Confounding factors in any epidemiological study or meta analysis constitutes a big risk.
  • The origins of such risks arise within the immense scope for concomitant variables to influence results - while at the same time not coming to the intention of researchers.
  • Usually epidemiology focuses attention upon 'outcome' and physiological factors that may give rise to an 'outcome', such as cancer. This is both laudable and dangerous.
  • As an ambition to link cause with effect epidemiology is laudable, but at all times it should be remembered that a lot of physiology and biochemistry resides between epi-physiological factors (risk-factors) and any adverse health outcome.
  • As science goes epidemiology should take steps to guard against thinking any epidemiological association is causal until any such association is backed by sound explanations and understanding of how the epi-physiological factors it has studied come to bear upon the all important physiological process, checks and balances, that give rise to a result.
  • Those who follow on to read epidemiological write-ups should do the same.


It's likely Confuscious would have been more concise and summary:


Learning without thought is labour lost;
Thought without learning is perilous.

Epidemiology is learning perhaps;
Physiology explained to link perceived epiphysiological risk-factors with adverse health outcomes is learning accompanied by insight.


Since Evenki peoples survive mostly upon reindeer meat, fat, offal and blood I'd be curious to learn if incidence of breast cancer in these peoples is in accord with what this study might supposedley encourage us to predict. I have gounds to be sceptical, becuase levels of cholesterol in these peoples have been studied along with incidence of heart disease related mortality. Lipid profiles (levels of cholesterol) of these people are enviable, and incidence of heart disease related mortality is reported not to be at all high.


Epidemiological studies are limited by the nature of the populations they study and the limits of parameters considered worthy of being measured and oncorporated. Dietary questionnaires greatly limit the parameters that are subjected to scrutiny. To my mind this write-up would benefit from more and additional discussion of all important physiological eventualities that may arise between dietary choices exercised in adolescence and cancer outcomes later in life.

Competing interests: None: Christopher Palmer became interested in health science and health politics at the beginning of 2009. He has spent the last three years researching the fat/cholesterol hypothesis considering himself a full-time and freelancing researcher despite the 'day-job'. Interests now major on the possible and increasingly plausible methylation/homocysteine/oxycholesterol etiology for atherogenicity and CVD. Contact by email to cjp.321.321@gmail.com

22 June 2014
Christopher J Palmer
Driver (LGV) and lay researcher reading health science
No affilations.
Stockport, SK7 3LA