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.

In the tables, statistically significant findings are in red type. In order for the rate to be statistically significant, the confidence interval (the numbers in the parentheses) must be either less than or greater than 1.00. If you are not familiar with statistics, click here for a quick explanation of disease rate statistics.

Contents

• Studies
• Death Rates (Standardized Mortality Ratios)
• 1999 Meta-Analysis Results
• 2009 Epic-Oxford Results
• 2003 Epic-Oxford Preliminary Results
• Adventist Health Results
• Heidelberg Results (German Vegetarians)
• Conclusion
• Additional Reading
• References

Studies

For an explanation of the different types of studies and their pros and cons, please see the article Basics of Nutrition Research.

The following studies have compared disease rates between people with different diets but similar lifestyles:

• 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

Death Rates (Standardized Mortality Ratios)

The following studies compared the death rates (deaths per 100,000 people per year, under age 90) of their entire study population to the greater population in that region, known as a Standardized mortality ratios (SMRs). The SMRs were:

• EPIC-Oxford - 52% (8)
• Adventist Mortality Study - 49% (3)
• Health Food Shoppers - 56% (3)
• Oxford Vegetarian Study - 46% (3)
• Heidelberg Study - 48% (3)

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 (3), and the healthy volunteer effect (3) (healthy people are more likely to volunteer for studies than unhealthy people) but some difference may have been due to a generally healthier diet overall than in the population at large (3, 8).

1999 Meta-Analysis Results

The 1999 Meta-Analysis (3) compared vegetarian death rates to non-vegetarians (click here for cancer rates). Although there have been more recent studies on vegetarian mortality rates, the 1999 Meta-Analysis remains the one study that included vegetarians from both North America and Europe and still probably deserves the most weight of anything that has been released to date.

Table 1. Vegetarian vs. Non-vegetarian Death Rates.
Disease	Rates and Confidence Interval
Ischemic heart disease	Non-Veg 1.00 Vegetarians   .76 (.62, .94)
Cerebrovascular disease	Non-Veg 1.00 Vegetarians   .93 (.74, 1.17)
All causes	Non-Veg 1.00 Vegetarians   .95 (.82, 1.11)

Table 1 shows that vegetarians had a 24% lower risk of ischemic heart disease, but there was no difference for stroke or all causes.

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) 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.

Table 2. Causes of 68 Vegan Deaths
Disease	Number
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

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 shown in Table 2.

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.

2009 Epic-Oxford Results

Table 3. 2009 EPIC-Oxford Results
	Heart Disease	All Causes
Smokinga
Never	1.00	1.00
Former	1.19 (  .88, 1.60)	1.14 (1.02, 1.27)
Light	2.23 (1.35, 3.69)	1.86 (1.52, 2.27)
Heavy	3.30 (1.79, 6.10)	3.01 (2.42, 3.74)
BMIb, c
< 20	1.51 (  .89, 2.58)	1.32 (1.10, 1.58)
20-22.4	1.00	1.00
22.4-25	1.02 (  .67, 1.57)	.97 (  .84, 1.12)
25-27.4	1.42 (  .91, 2.22)	.93 (  .79, 1.09)
> 27.4	2.53 (1.66, 3.87)	1.19 (1.01, 1.41)
Alcoholc
< 1 g/day	1.37 (  .99, 1.92)	1.14 (1.01, 1.30)
1-7 g/day	1.00	1.00
8-15 g/day	.73 (  .48, 1.11)	.85 (  .74,   .99)
> 16 g/day	.87 (  .58, 1.31)	.92 (  .78, 1.08)
aAdjusted for age and sex. Heavy smokers smoked > 15 cigarettes/d; light smokers include all other current smokers; never smokers are those who have never smoked > 1 cigarettes/day for > 1 y. | bBody Mass Index = weight in kg divided by height in meters squared. | cAdjusted for age, sex, and smoking.

EPIC-Oxford recruited participants from 1993 to 1999. Results of death from heart disease, stroke, and all causes through June 2007 were released in 2009. There were no statistically significant differences between vegetarians and meat-eaters for deaths from any of these diseases. There was also no difference between regular meat-eaters, fish-only meat eaters, and vegetarians. Vegans were not separated from the vegetarian group.

Table 3 shows some significant findings (in red type) when breaking the population down into other categories.

As usual, smoking caused a significant risk for early death. And to think how natural tobacco barns smell...

A low or high BMI was also a fairly significant cause of early death. In many long-term prospective studies, the first 5 years of deaths are eliminated due to some participants having undiagnosed disease. Many such participants also have a low body weight. It does not appear that they removed the first five years of death from this analysis, so undiagnosed illness might be what is going on with the low BMI. Or it could just be that a low BMI increases the risk of early death.

As in many other studies, moderate alcohol drinkers fared well.

The authors stated:

Average meat intake among the meat eaters was only moderate, at 79 g/d in men and 67 g/d in women; these intakes are much lower than those reported in the National Diet and Nutrition Survey for the United Kingdom. Consumption of vegetables and fruit was higher among vegetarians than among nonvegetarians, but the differences were not large (< 20%). Thus, if high intakes of meat had an adverse effect and high intakes of fruit and vegetables had a beneficial effect, the relatively low meat intake and high fruit and vegetable intake of the nonvegetarians in this cohort could reduce the chance of observing lower mortality rates in the vegetarians than in the nonvegetarians.

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.

Adventist Health Results

The Adventist Health Study (1) is the only major study on the general health and mortality of vegetarians in the USA. Table 4 shows 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.

Table 4. Adventist Health Study Results
	Men		Women
	Vegetarians	Non-vegetarians	Vegetarians	Non-vegetarians
BMIa	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
aBMI - 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

Heidelberg Results (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. The authors state, "Being a vegan was associated with a higher mortality risk (1.59; 95% CI (confidence interval), 0.98-2.59) than being a lacto-ovo vegetarian (1.08; 95% CI, 0.86-1.34), when compared with nonvegetarians with moderate meat/ fish consumption, accounting for all other variables (data not shown)."

Table 5. Heidelberg Study Results
Activity	Rates and Confidence Interval	Notes
Smoking	Non-smoker 1.00 Smoker 2.00 (1.40, 3.00)	Mortality
Physical Activity	Low 1.00 Moderate   .62 ( .43, .89) High   .64 ( .44, .93)	Mortality
Meat Intake	Never 1.00 >3x per week 4.80 (1.90, 12.00)	Ischemic heart disease
Fish Intake	Never 1.00 >1x per month 2.10 (1.10,  4.00)	Ischemic heart disease

As you can see, these findings were not statistically significant, but they were close for the vegans. Also note that these "nonvegetarians" were semi-vegetarians, eating very little meat. It wouldn't surprise me to find out these vegans did not do much to supplement their diet with vitamin B12.

Other results of interest are shown in Table 5.

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.

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.

Additional Reading

Do Vegetarians Live Longer? by Paul Appleby of EPIC.

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References