|Dietary habits and mortality in 11,000 vegetarians and health conscious people: results of a 17 year follow up|
|Saturday, 28 September 1996 00:00|
"Objective - To investigate the association of dietary habits with mortality in a cohort of vegetarians and other health conscious people."
"Subjects - 4336 men and 6435 women recruited through health food shops, vegetarian societies, and magazines."
"Main outcome measures - Mortality ratios for vegetarianism and for daily versus less than daily consumption of wholemeal bread, bran cereals, nuts or dried fruit, fresh fruit, and raw salad in relation to all cause mortality and mortality from ischaemic heart disease, cerebrovascular disease, all malignant neoplasms, lung cancer, colorectal cancer, and breast cancer."
"Results - Overall the cohort had a mortality about half that of the general population. Within the cohort, daily consumption of fresh fruit was associated with significantly reduced mortality from ischaemic heart disease (rate ratio adjusted for smoking 0.76 (95% confidence interval 0.60 to 0.97)), cerebrovascular disease (0.68 (.047 to 0.98)), and for all causes combined (0.79 (0.70 to 0.90))."
"After a mean of 16.8 years of follow up (maximum 21.3 years) mortality was substantially lower than in the general population; the standarised mortality ratio for all causes of death was 0.56 (95% confidence interval 0.53 to 0.59) for men and women combined. Table 2 shows the standardized mortality ratios were significantly below one for all malignant neoplasms, cancer of the stomach, cancer of the large intestine and rectum (subsequently referred to as colorectal cancer), cancer of the bronchus and lung, diabetes mellitus, diseases of the circulatory system, diseases of the respiratory system, diseases of the digestive system, and diseases of the genitourinary system. Among women, standardized mortality ratios were significantly below one for all malignant neoplasms, cancer of the bronchus and lung, diabetes mellitus, mental disorders, diseases of the circulatory system, diseases of the respiratory system, and diseases of the digestive system."
"Smoking was associated with a 52% increase in all cause mortality, increasing to 100% in people who smoked = 15 cigarettes a day."
"The low standarised mortality ratio of the cohort, 0.56 for men and women combined, is similar to that in comparable cohorts: 0.46 in the Oxford Vegetarian Study, 0.48 in a cohort of German vegetarians and health conscious people, and 0.56 in a cohort of Californian Seventh Day Adventists. The low overall mortality was mostly due to low death rates from diseases of the circulatory system, diseases of the respiratory system, and cancer of the bronchus and lung compared with the general population. This is probably mainly accounted for by the low proportion of smokers in the cohort (19% smokers overall)."
"This study was initially set up to test the hypotheses that daily consumption of wholemeal bread (as indicator of a high fibre diet) and vegetarian diet are associated with a reduction in mortality from ischaemic heart disease; the reduction in mortality associated with both of these dietary factors was not significant. We did, however, find that daily consumption of fresh fruit was associated with a significant reduction in mortality from ischaemic heart disease (24%), cerebrovascular disease (32%), and all causes of death combined (21%), and was associated with a non-significant reductions in mortality from all other cause of death examined."
"Fruit was included on the questionnaire as a possible indicator of a high fibre diet but was not part of the original hypothesis, so cause should be applied in looking at these results in isolation. Nevertheless, our findings are broadly consistent with the results of several other studies. For all cause mortality, Kahn et all reported odds ratios of 0.89 and 0.72 for frequent versus infrequent consumption of fruit or fruit juice and green salad respectively, Padley et all reported a 31% reduction with a high intake of foods rich in vitamin C and in ß carotene, and Enstrom et all reported a 23% reduction associated with a high vitamin C consumption. Fruit is an important source of vitamin C. Fruits and vegetables, carotene containing fruit and vegetables, apples, and foods rich in vitamin C and ß carotene have all been reported to protect against ischaemic heart disease. Fruit and vegetables have also been reported to protect against stroke, as have potassium and vitamin C - nutrients for which fruit is an important source."
"Of the other associations examined, only two were significant. Daily consumption of wholemeal bread was associated with a 12% reduction in all cause mortality, but the protection was much less than that for fresh fruit (21%) and became non-significant after fruit was adjusted for. Daily consumption of raw salad was associated with a 26% reduction in mortality from ischaemic heart disease, slightly greater than that for fresh fruit (24%). After each of these variables was adjusted for the other, salad was more closely associated with mortality, but the reduction in risk associated with fruit remained substantial (18%) and both these foods may have a protective effect."
Key, Timothy J. A.; Thorogood, Margaret; Appleby, Paul; and Burr, Michael L., "Dietary habits and mortality in 11,000 vegetarians and health conscious people: results of a 17 year follow up", BMJ (British Medical Journal), September 28, 1996, Vol. 313, Num. 0, pp. 775-779