Written by Marcia J. Egles, MD. In a large study of the British population, vegetarians (not consuming meat or fish) had 32% lower risk of hospitalization or death from ischemic heart disease than did the non-vegetarians.
British vegetarians have a significantly reduced risk of ischemic heart disease compared to their fellow meat eaters, according to a recent large study from the University of Oxford.(1) The EPIC-Oxford study documents a 32% lower risk of hospitalization or death from ischemic heart in vegetarians as compared with the non-vegetarians. Ischemic heart disease refers to heart disease caused by insufficient blood flow to the heart, generally because of arterial narrowing from coronary artery disease. Ischemic heart disease is the leading cause of death for both men and women, accounting for approximately 600,000 deaths in the United States every year. (2) Heart attacks (myocardial infarction) and chest pain from angina are examples of ischemic heart disease.
The EPIC (European Prospective Investigation into Cancer and Nutrition)-Oxford study (1) is remarkable in its size, its number of vegetarians, and its duration. Between 1993 and 1999, the study recruited over 57,000 “health-conscious” adults willing to complete an extensive baseline questionnaire regarding their medical histories and behaviors such as dietary habits, exercise, and smoking. The recruitment targeted vegetarians as well as the United Kingdom’s general population. About a third of the participants reported consuming a vegetarian diet. (The study defined a vegetarian diet as a diet without meat or fish.) Two thirds of the vegetarians had followed a vegetarian diet for more than 5 years. Participants were required to be less than 90 years of age at the start of the study, and to have no known cancer or heart disease. The average age of the participants at the study’s start was 59.4 years for the non-vegetarians and 57.7 for the vegetarians. After exclusions, 46,694 participants remained available for analysis, with an average follow-up of 11.6 years in this prospective study. Women comprised 76% of the participants.
There was a low prevalence of smokers in all the study participants ranging from 10% of the vegetarian women to 15% of the non-vegetarian men. Overall, the two groups had normal weights, the vegetarians with an average Body Mass Index (BMI) of 23.4 kg per meter squared and the non-vegetarians with an average BMI of 24.9. A healthy body mass index (BMI) is considered to be between 18.5 and 24.9 kilograms of body weight per meter squared of body height. The overall prevalence of self-reported risk factors for the two groups was low with only 1% having diabetes, 9% having hypertension (high blood pressure) and 5% having hyperlipidemia.
The objective of this study was to compare the cases of ischemic heart disease in the population of British vegetarians to the cases in the population of otherwise similar British non-vegetarians, and to determine whether any associations were mediated through known risk factors such as high blood pressure and serum lipid concentrations. The number of cases of ischemic heart disease was gathered through linkages with hospital records and death certificates. Over an average follow-up period of 11.6 years, there were 1066 hospital admissions and 169 deaths due to ischemic heart disease.
After adjustment for age, smoking, alcohol, physical activity and educational level, the vegetarians had a 32% lower risk (hazard ratio 0.68; 95% confidence interval 0.58,0.81) of hospitalization or death from ischemic heart disease than did the non-vegetarians. This risk was only slightly less pronounced after statistical adjustment for BMI.
The results were largely explained through reduced levels of established risk factors in the vegetarians. The vegetarians had better lipid profiles than did the non-vegetarians. On average, their non-HDL serum cholesterols were 0.45 mmol/ L lower than that the non-vegetarians. A 16% lower risk of ischemic heart disease might be predicted from this cholesterol reduction alone (3). A further 10% lower risk (4) might be due to the vegetarians having lower systolic blood pressures, on average 3.3 milimeters mercury lower than the non-vegetarians.
This study supports the importance of diet in the prevention of ischemic heart disease.
Source: Crowe, Francesca L., et al. “Risk of hospitalization or death from ischemic heart disease among British vegetarians and nonvegetarians: results from the EPIC-Oxford cohort study.” The American journal of clinical nutrition 97.3 (2013): 597-603.
© 2013 American Society for Nutrition
Posted April 17, 2013.
Marcia Egles, MD, graduated from Vanderbilt University School of Medicine in 1986. She completed her residency in Internal Medicine at St. Louis University Hospital. Dr. Egles is certified in Internal Medicine and is a member of the American College of Physicians. She resides in Avon, IN with her husband and two sons.
References:
- Francesca L. Crowe et al. Risk of hospitalization or death from ischemic heart disease among British vegetarians and nonvegetarians: results from the EPIC-Oxford cohort study Am J Clin Nutr 2013: 97: 597-603.
- Kenneth D. Kochanek, M.A.; Jiaquan Xu, M.D.; Sherry L. Murphy, B.S.; Arialdi M. Minin˜o, M.P.H.; and Hsiang-Ching Kung, Ph.D., Division of Vital Statistics National Vital Statistics Report (Center for Disease Control, United States) vol . 60, number 3, December 29, 2011.
- Prospective Studies Collaboration, Lewington, S., Whitcock et al. Blood cholesterol and vascular mortality: a meta-analysis of individual data from 61 prospective studies with 55,000 vascular deaths. Lancet 2007: 370:1829-39.
- Lewington, S et al. Prospective Studies Collaboration. Age Specific relevance of usual blood pressure to vascular mortality: a meta-analysis of individual data for one million adults in 61 prospective studies. Lancet 2002: 360: 1903-13.
