2012 meta-analysis on veg mortality and cancer incidence

A new meta-analysis on vegetarian mortality and cancer has been released (1). It found a statistically reduced rate for vegetarians in terms of ischemic heart disease mortality and cancer incidence. It did not find a difference for all cause mortality or stroke.

Comments I have added to Disease Rates of Vegetarians and Vegans on VeganHealth.org:

“Although the 2012 meta-analysis by Huang et al. (1) is more recent, it may not be as reliable as the 1999 meta-analysis [by Key et al.] because it includes a 1984 study on Zen priests (2) who were mostly semi-vegetarian and which used a standardized mortality ratio (comparing all the Zen priests to the greater population rather than comparing the “vegetarians” to non-vegetarians within the same group). The Heidelberg Study results were also included and its control group was semi-vegetarians, which means there were semi-vegetarians in both the “vegetarian” and “non-vegetarian” group in the 2012 meta-analysis; while this is not ideal, it should have biased the results against finding a beneficial effect of a vegetarian diet. In its favor, the 2012 meta-analysis includes data from EPIC-Oxford that was not available for the 1999 meta-analysis.”

There is a table with the confidence intervals at the link above.


1. Huang T, Yang B, Zheng J, Li G, Wahlqvist ML, Li D. Cardiovascular Disease Mortality and Cancer Incidence in Vegetarians: A Meta-Analysis and Systematic Review. Ann Nutr Metab. 2012 Jun 1;60(4):233-240. (Link)

2. Ogata M, Ikeda M, Kuratsune M. Mortality among Japanese Zen priests. J Epidemiol Community Health. 1984 Jun;38(2):161-6. (Link)

2 Responses to “2012 meta-analysis on veg mortality and cancer incidence”

  1. Peter Says:


    what did you meant with this :”It did not find a difference for all cause mortality or stroke”.

    Do I miss something here? The abstract of the meta-analysis includes this:

    “All-cause mortality in vegetarians was 9% lower than in nonvegetarians (RR = 0.91; 95% CI, 0.66-1.16)”.

  2. Jack Norris RD Says:


    The abstract was misleading because it listed findings that were not statistically significant. But if you notice, the final sentence of the abstract was, “Our results suggest that vegetarians have a significantly lower ischemic heart disease mortality (29%) and overall cancer incidence (18%) than nonvegetarians.” For a finding to be statistically significant, 1.00 cannot be within the 95% confidence interval (CI). In the case of the all-cause mortality, it’s not even very close to statistical significance.

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