Disease Rates of Vegetarians and Vegans

Below is a summary of the research done on mortality and disease rates of vegetarians. It does not include cancer rates which can be found on the Cancer, Vegetarianism, and Diet page.

For a concise explanation of the different types of studies and their pros and cons, please see the article, Nutrition Research: What You Should Know.

The following studies have looked at disease rates in Western vegetarians:

Adventist Mortality (USA)
Adventist Health (USA)
Health Food Shoppers (UK
Oxford Vegetarian (UK)
Heidelberg (Germany)
1999 Meta Analysis - compilation of the data from the above five studies
EPIC-Oxford (UK) - in progress
Adventist Health Study-2 (USA) - in progress

The point of these studies were to compare disease rates between people with different diets but similar lifestyles. Four studies also compared the death rates (deaths per 100,000 people per year, under age 90) of the entire study population to the greater population in that region, known as a Standardized mortality ratios (SMRs). The SMRs³ were:

Adventist Mortality Study - 49%
Health Food Shoppers - 56%
Oxford Vegetarian Study - 46%
Heidelberg Study - 48%

This means that people in these studies died at about half the rates of the overall populations in their region. The researchers considered most of this difference to be due to lower smoking rates in the study groups, but some difference may have been due to a generally healthier diet overall than in the population at large.³

Adventist Health Study

The Adventist Health Study¹ is the only major study on the general health and mortality of vegetarians in the USA. Here are the main results (except for cancer).

Data collected from 1976-1988
34,192 participants, members of the Seventh-day Adventist church
29% were vegetarian; 7-10% of the vegetarians were vegan.

Results:

	Men		Women
	Vegetarians	Non-vegetarians	Vegetarians	Non-vegetarians
BMI	24.3	26.2	23.7	25.9
Heart disease	38% Lower for Men		No Difference for Women
Overall mortality	Lived 3.21 more yrs		Lived 2.52 more yrs
BMI - Body Mass Index. A measure of healthy body weight. Lower than 20 is underweight, while ≥ 25 is overweight.

Compared to the non-vegetarians, vegetarians had about:

1/2 the high blood pressure and diabetes
2/3 the rheumatoid arthritis

Life expectancies in the Adventist Health Study were published in 2001.² They showed that white, non-Hispanic Seventh-day Adventists live longer than other white Californians (7.28 more years for men, 4.42 more years for women). According to the researchers, this group of Seventh-day Adventists were the longest-lived, formally studied population in the world (with an average life span of 78.5 years for men, 82.3 for women).

The following variables were shown to increase life expectancy:

vegetarian diet
eating nuts regularly
physical activity
lower body weight
no smoking

1999 Meta-Analysis

The 1999 Meta-Analysis³ compared vegetarian death rates to non-vegetarians with the following results (click here for cancer rates). Vegetarians had a 24% lower risk of ischemic heart disease, but there was no difference for stroke or all causes.

	Ischemic heart disease	Cerebrovascular disease	All causes
Vegetarian death rate	.76 (.62, .94)^{Stats Note}	.93 (.74, 1.17)	.95 (.82, 1.11)

There was also a sub-section that separated the vegetarian group into lacto-ovo vegetarians and vegans. The Health Food Shoppers Study was left out of this portion of the analysis because it did not distinguish between lacto-ovo vegetarians and vegans.⁶ Compared to 31,766 people who ate meat at least once per week:

Occasional meat eaters (8,135 people who ate meat less than once per week) had a 20% reduced rate of dying of heart disease and a 10% reduced rate of overall mortality.
Those who ate no meat other than fish (2,375 people) had a 34% reduced rate of dying from heart disease and an 18% reduced rate of overall mortality.
Lacto-ovo vegetarians (23,265 people) had a 38% reduced rate of dying from lung cancer, a 34% reduced rate of dying from heart disease, and a 15% reduced rate of mortality.
Vegans (753 people) had a heart disease rate of .74 (.46, 1.21)^{Stats Note} and a mortality rate of 1.00 (.70, 1.44). There were no statistically significant differences between the vegans and the regular meat-eaters for any causes of death.

There were only 68 vegan deaths in this population over the course of the studies, as distinct from 3,017 for regular meat-eaters. The breakdown of vegan deaths is as follows:

Disease	Vegan Deaths
Heart disease	17
Stroke	4
Lung cancer	2
Stomach cancer	2
Colorectal cancer	1
Breast cancer	0
Prostate cancer	0
Other causes	42
Total	68

In personal communication, an author of the study said the "Other causes" category of death did not appear to be diet-related and so was not subdivided into smaller categories.⁴

Could Vegans Have Fared Better?

It should be noted that when these studies began, the full importance of vegans' getting a reliable supply of vitamin B12 was not known, nor was the need for vegans to maximize their omega-3 status.

German Vegetarians

In 2005, results from 21 years of follow-up of the Heidelberg Study were published.⁵ The 1999 Meta-Analysis included only 11 years of follow-up from this population.

There were only 60 vegans in the Heidelberg Study, which was 3% of the study group and not enough to provide much information on vegan mortality. Additionally, the "non-vegetarians" in this group were mostly semi-vegetarians, eating very little meat.

Results of interest:

Smoking	Smoker	Non-smoker
Mortality	2.0 (1.4, 3.0)^{Stats Note}	1.0

Physical Activity	Moderate	High
Mortality	.62 (.43, .89)	.64 (.44, .93)

Meat intake	> 3x per week	Never
Ischemic Heart Disease	4.8 (1.9, 12)	1.0

Fish intake	> 1x per month	Never
Ischemic Heart Disease	2.1 (1.1, 4.0)	1.0

The authors had the following to say about physical activity:

Our findings corroborate epidemiologic evidence indicating that regular and vigorous physical activity is an effective means of preventing circulatory diseases and cancers at different sites.

2003 Epic-Oxford Preliminary Results

In 2003, preliminary results from EPIC-Oxford (Oxford component of the European Prospective Investigation into Cancer and Nutrition) comparing death rates of 46,562 subjects were reported.⁷ About 33% of the subjects were vegetarian (including many vegans). The results showed no statistically significant differences between the vegetarians and non-vegetarians in any of the mortality categories which included cancer, circulatory disease, ischemic heart disease, cerebrovascular disease (stroke), all other causes, and all causes combined.

Conclusion

In summary, not enough is yet known about vegan mortality to draw any conclusions other than that vegans do not have unusually high rates of mortality and they probably do better than the average person due either to diet or a healthier lifestyle.

References

1. Fraser GE. Associations between diet and cancer, ischemic heart disease, and all-cause mortality in non-Hispanic white California Seventh-day Adventists. Am J Clin Nutr. 1999 Sep;70(3 Suppl):532S-538S.
2. Fraser GE, Shavlik DJ. Ten years of life: Is it a matter of choice? Arch Intern Med. 2001 Jul 9;161(13):1645-52.
3. Key TJ, Fraser GE, Thorogood M, Appleby PN, Beral V, Reeves G, Burr ML, Chang-Claude J, Frentzel-Beyme R, Kuzma JW, Mann J, McPherson K. Mortality in vegetarians and nonvegetarians: detailed findings from a collaborative analysis of 5 prospective studies. Am J Clin Nutr. 1999 Sep;70(3 Suppl):516S-524S.
4. Personal communication with Paul Appleby. December 16, 2002.
5. Chang-Claude J, Hermann S, Eilber U, Steindorf K. Lifestyle determinants and mortality in German vegetarians and health-conscious persons: results of a 21-year follow-up. Cancer Epidemiol Biomarkers Prev. 2005 Apr;14(4):963-8.
6. Personal communication with Paul Appleby. January 12, 2003.
7. Key TJ, Appleby PN, Davey GK, Allen NE, Spencer EA, Travis RC. Mortality in British vegetarians: review and preliminary results from EPIC-Oxford. Am J Clin Nutr. 2003; 78(3 Suppl):533S-538S.