Mortality in vegetarians and nonvegetarians: detailed findings from a collaborative analysis of 5 prospective studies.

We combined data from 5 prospective studies to compare the death rates from common diseases of vegetarians with those of nonvegetarians with similar lifestyles. A summary of these results was reported previously; we report here more details of the findings. Data for 76172 men and women were available. Vegetarians were those who did not eat any meat or fish (n = 27808). Death rate ratios at ages 16-89 y were calculated by Poisson regression and all results were adjusted for age, sex, and smoking status. A random-effects model was used to calculate pooled estimates of effect for all studies combined. There were 8330 deaths after a mean of 10.6 y of follow-up. Mortality from ischemic heart disease was 24% lower in vegetarians than in nonvegetarians (death rate ratio: 0.76; 95% CI: 0.62, 0.94; P<0.01). The lower mortality from ischemic heart disease among vegetarians was greater at younger ages and was restricted to those who had followed their current diet for >5 y. Further categorization of diets showed that, in comparison with regular meat eaters, mortality from ischemic heart disease was 20% lower in occasional meat eaters, 34% lower in people who ate fish but not meat, 34% lower in lactoovovegetarians, and 26% lower in vegans. There were no significant differences between vegetarians and nonvegetarians in mortality from cerebrovascular disease, stomach cancer, colorectal cancer, lung cancer, breast cancer, prostate cancer, or all other causes combined.

Mortality in vegetarians and non-vegetarians: a collaborative analysis of 8300 deaths among 76,000 men and women in five prospective studies.

OBJECTIVE: To compare the mortality rates of vegetarians and non-vegetarians. DESIGN: Collaborative analysis using original data from five prospective studies. Death rate ratios for vegetarians compared to non-vegetarians were calculated for ischaemic heart disease, cerebrovascular disease, cancers of the stomach, large bowel, lung, breast and prostate, and for all causes of death. All results were adjusted for age, sex and smoking. A random effects model was used to calculate pooled estimates of effect for all studies combined. SETTING: USA, UK and Germany. SUBJECTS: 76,172 men and women aged 16-89 years at recruitment. Vegetarians were those who did not eat any meat or fish (n = 27,808). Non-vegetarians were from a similar background to the vegetarians within each study. RESULTS: After a mean of 10.6 years of follow-up there were 8330 deaths before the age of 90 years, including 2264 deaths from ischaemic heart disease. In comparison with non-vegetarians, vegetarians had a 24% reduction in mortality from ischaemic heart disease (death rate ratio 0.76, 95% CI 0.62-0.94). The reduction in mortality among vegetarians varied significantly with age at death: rate ratios for vegetarians compared to non-vegetarians were 0.55 (95% CI 0.35-0.85), 0.69 (95% CI 0.53-0.90) and 0.92 (95% CI 0.73-1.16) for deaths from ischaemic heart disease at ages <65, 65-79 and 80-89 years, respectively. When the non-vegetarians were divided into regular meat eaters (who ate meat at least once a week) and semi-vegetarians (who ate fish only or ate meat less than once a week), the ischaemic heart disease death rate ratios compared to regular meat eaters were 0.78 (95% CI 0.68-0.89) in semi-vegetarians and 0.66 (95% CI 0.53-0.83) in vegetarians (test for trend P< 0.001). There were no significant differences between vegetarians and non-vegetarians in mortality from the other causes of death examined. CONCLUSION: Vegetarians have a lower risk of dying from ischaemic heart disease than non-vegetarians.

Coffee consumption and cause-specific mortality. Association with age at death and compression of mortality.

The relationship between reported coffee consumption and specific causes of death was examined in 9484 males enrolled in the Adventist Mortality Study in 1960 and followed through 1985. Coffee consumption was divided into three levels: less than 1 cup per day, 1-2 cups per day, and greater than or equal to 3 cups per day. Approximately one third of the subjects did not drink coffee. Cause-specific mortality rates were compared using survival analysis including Cox's proportional hazard model, and controlling for potential confounders such as body mass index, heart disease and hypertension at baseline, race, physical activity, marital status, educational level, smoking history, and dietary pattern. Inclusion of interaction terms between coffee consumption and attained age as time-dependent covariates allowed the hazard ratio to vary with age. Univariate analyses showed a statistically significant association (p less than 0.05) for coffee consumption and mortality for most endpoints. Multivariate analyses showed a small but statistically significant association between coffee consumption and mortality from ischemic heart disease, other cardiovascular diseases, all cardiovascular diseases, and all causes of death. For the major causes of death, the hazard ratios decreased from about 2.5 at 30 years of age to 1.0 around 95 years of age. These results indicate that abstinence from coffee leads to compression of mortality rather than an increase in lifespan.

Body mass index and patterns of mortality among Seventh-day Adventist men.

This study examines the relationship between body mass index (BMI) and 26-year mortality among 8828 nonsmoking, nondrinking Seventh-day Adventist men, including 439 who were very lean (BMI less than 20 kg/m2). The adjusted relative risk comparing the lowest BMI quintile (less than 22.3) to the highest (greater than 27.5 kg/m2) was 0.70 (95 percent CI 0.63-0.78) for all cause mortality, 0.60 (95 percent CI 0.43-0.85) for cerebrovascular mortality, and 0.80 (95 percent CI 0.61-1.04) for cancer mortality. Very lean men did not show increased mortality. To assess whether the protective effect associated with low BMI is modified by increasing age, the product term between BMI and attained age (age at the end of follow-up or at death) was included as a time-dependent covariate. For ischemic heart disease mortality, age-specific estimates of the relative risk for the lowest quintile relative to the highest ranged from 0.32 (95 percent CI, 0.19-0.52) at age 50 to 0.71 (95 percent CI, 0.56-0.89) at age 90. Interaction was also seen for the next lowest quintile (22.4-24.2). There was a significant trend of increasing mortality with increasing BMI for all endpoints studied. For cancer and cerebrovascular mortality the P-values for trend were 0.0001 and 0.001 respectively. For the other endpoints the P-values were less than 0.0001. Thus, there was no evidence for a J-shaped relationship between BMI and mortality in males. While the protective effect associated with the lowest BMI quintile decreased with increasing age for ischemic heart disease mortality, it remained greater than one at all ages. The relatively large number of subjects who were lean by choice, rather than as a result of preclinical disease or smoking, may explain these findings.

Cause-specific mortality among physicians with differing life-styles.

We compare the mortality experience of medical school graduates from Loma Linda University (LLU [n = 4342]) and the University of Southern California (USC [n = 2832]) with each other and with that of contemporaneous, white, American men. When compared with US white men from the general population, both USC and LLU graduates had below expected deaths for all causes (USC, standardized mortality ratio [SMR] = 76; LLU, SMR = 56), although deaths due to cerebrovascular disease, airplane accidents, and suicides were elevated for USC (SMRs = 132, 360, and 218, respectively). The LLU graduates had a risk similar to that of the USC graduates for fatal cancer, with a mortality ratio (MR) of 0.92 (95% confidence interval, 0.67 to 1.26); but half the risk of fatal atherosclerotic disease, with MRs of 0.58 (0.46 to 0.73) and 0.66 (0.43 to 0.99) for coronary and cerebrovascular disease, respectively; and three times the risk of fatal airplane accidents. The overall mortality rate of LLU physicians was only 75% as high as that of the USC physicians and only 56% as high as that of the US male population at large. We attribute this reduced mortality mainly to the low cardiovascular mortality rates, which may be accounted for by the life-style of the substantial proportion of Seventh-day Adventists among LLU graduates.

Self-report of physical activity and patterns of mortality in Seventh-Day Adventist men.

The Adventist Mortality Study provides 26-year follow-up through 1985 for 9484 males who completed a lifestyle questionnaire in 1960. The relationship of self-reported physical activity and all cause and disease-specific mortality was examined by survival analysis and with the Cox proportional hazards model, controlling for demographic and lifestyle characteristics. Moderate activity was associated with a protective effect on cardiovascular and all cause mortality in both analyses. In the Cox model, age-specific estimates of relative risk (RR) were obtained for several endpoints due to a significant interaction between level of physical activity and attained age (age at death or end of follow-up). This model permits calculation of the age at which the RR = 1.0, or the age at crossover of risk. For moderate activity, this age was 95.6 years (95% confidence intervals, 81.7-109.4 years) for all cause mortality and 91.5 years (95% confidence intervals, 79.0-104.0 years) for cardiovascular mortality. While the protective effect on mortality associated with moderate activity decreased with increasing age, it remained significant to the verge of the present life span.

Determinants of eight-year diet recall ability.

This study investigated how well people can recall their food habits of years ago and identified factors that predict recall ability. We examined the self-reported dietary intakes of 623 people, about one-third of whom were vegetarians. Subjects included cancer cases and controls who were selected as a representative sample of the Adventist Health Study population. We compared the initial (1976) dietary data with data recalled retrospectively in 1984. The initial and retrospective assessments made use of the same food frequency questionnaire for the same 35 food items. Recall ability was measured in two ways: exact recall and recall error. Persons with a stable diet had by far the best recall. Vegetarian status and level of education also were determinants of exact recall, whereas diet stability and education were the most significant determinants of recall error. These results indicate that some individuals, particularly those with a stable diet, those with a vegetarian diet, and those with more education, are able to recall their past dietary practices with reasonable reliability.

Reliability of eight-year diet recall in cancer cases and controls.

We addressed three questions concerning diet recall in a population of 181 incident cancer cases diagnosed between 1976 and 1984 in the Adventist Health Study, and 225 controls randomly selected from the same population after removing cancer cases: (1) Are recalls of past dietary habits reliable? (2) Does recall ability differ between cancer cases and controls? and (3) Are current or retrospectively recalled reports the best estimator of past dietary practices? Three sets of dietary data were compared using a 35-item nonquantitative food frequency questionnaire: initial reports in 1976, recalled reports obtained retrospectively in 1984, and current reports for 1984. Recall ability was evaluated for individual foods and for all foods combined by comparing recall error scores summing the absolute differences between initial and recalled frequencies. Means and medians for all three food groups were similar for cases and controls. The Spearman rank-order correlations between pairs of reports (initial/recalled, initial/current, and recalled/current) averaged 0.48, 0.41, and 0.62, respectively. A crude difference of 2.0 between cases and controls (p less than 0.05) in the recall error score indicated that cases on the average recalled two foods one frequency category closer to the initial estimate compared with controls. The case-control difference decreased to a nonsignificant 0.4 (p = 0.07) in multivariate analysis that conditioned on dietary changes. On the average, recalled reports estimated initial reports one frequency category closer than did current reports for three foods (p less than 0.001), primarily because of changes in dietary habits.

Husband-wife diet concordance and changes in dietary practices by surviving spouses of cancer cases.

Diet concordance and changes in dietary practices by surviving spouses of cancer cases were investigated by studying 69 husband-wife pairs during an eight-year period spanning the death from cancer of one spouse. The data base consisted of reports for each cancer case from the Adventist Health Study (AHS) where a surviving spouse was available. Two questions were addressed. 1. Do husbands and wives eat similar diets? 2. Did survivors change their diet practices during the eight-year period? Three sets of dietary data were compared with the AHS food frequency questionnaire: reports made in 1976 by cases; reports made in 1976 by their spouses (initial); and the spouses' reports in 1984 (current). Diet concordance and dietary changes for 35 key food groups were evaluated both for individual foods and across foods by computing recall scores. The results were analyzed with univariate and multivariate methods. Comparison of means and Spearman rank-order correlations revealed good initial concordance between the spouses, which was not significantly related to age, sex, or education. However, eight years later subsequent to the deaths of the cases, the agreement was poor because the surviving spouses had changed their diets. The changes in dietary practices were significantly related to education and body mass index in univariate analysis but not in analysis of covariance. These results indicate that retrospective recall by spouses for the cases rather than the spouses' own current reports should be used as an estimate for the deceased cases. Repeated recalls are necessary to increase reliability.

Long-term (24-year) recall reliability in cancer cases and controls using a 21-item food frequency questionnaire.

The following two questions concerning diet recall were addressed when studying 117 incident cancer cases and 99 controls from the Adventist Mortality Study. Are recalls of past dietary habits reliable? Does recall ability differ between cancer cases and controls? Two sets of dietary data were compared using the American Cancer Society's food frequency questionnaire--as reported in 1960 and recalled in 1984. Ability to recall 21 key food items was evaluated both for individual foods and a combination of all foods by comparing recall scores. The comparison revealed that among food groups, 24-year recall ability varied greatly. There was no significant difference in recall ability between cancer incident cases and controls after controlling for factors that may be related to recall ability (e.g., age, education, and sex). Also, there was no significant difference in recall ability among subjects with or without other chronic diseases likely to affect diet pattern. The results revealed no significant differences in recall ability by sex and body mass index; however, significant differences by vegetarian status and diet stability were found. Significant differences by educational level were found only in univariate analysis.

Determinants of long-term (24-year) diet recall ability using a 21-item food frequency questionnaire.

This study sought to determine how well individuals are able to recall accurately their food habits of 24 years ago and identify those factors that are predictive of recall ability. We investigated the self-reported dietary intakes of 216 people, one-half of whom were vegetarians, including cancer cases and controls. We compared 21 key food items reported in 1960 with the same data reported in 1984. Recall ability was the highest for persons with stable diets. Vegetarian status, education, and church attendance were the other significant determinants of exact recall; age and church attendances were the only significant determinants of recall error. After excluding nonusers of particular foods, we found a positive correlation between frequency of use and recall ability.

Breast cancer survival rates among Seventh-day Adventists and non-Seventh-day Adventists.

Survival rates were compared among 282 Seventh-day Adventists and 1675 other white female cancer cases following diagnosis during the 30-year period, 1946 to 1976, at two California hospitals owned and operated by the Seventh-day Adventist Church. The Adventist women had a more favorable 5-year relative survival pattern than the other women (69.7% vs. 62.9%) as well as a higher probability of not dying of breast cancer. The differences, however, were no longer significant when stage at diagnosis was taken into account. It seems likely that the lower breast cancer death rates reported among Seventh-day Adventist women as compared with the general population result in part from better survival patterns due to earlier diagnosis and treatment.

Maternal drinking behavior and decreased intrauterine growth.

Reduced intrauterine growth has been a widely observed effect of maternal alcohol use during pregnancy in both animals and humans, although results in studies of humans have been inconsistent. The goal of this prospective study was to evaluate the relative importance of volume, frequency, and beverage source of alcohol as determinants of infant birthweight, while adjusting for other known determinants using multivariate techniques. In a sample of 5,093 maternal-infant pairs, 44 potential determinants of intrauterine growth were evaluated. The frequency of beer drinking, controlled for wine drinking, liquor drinking, and other variables, was found to contribute independently to a reduction of intrauterine growth, as measured by birthweight adjusted for gestational age. Of the variables explored, 11, including cigarette smoking and caffeine intake, were found to contribute significantly (R2 = 32%; p less than 0.001) to the variance. The effect of beer drinking was most apparent in the most frequently drinking 3% of gravidas. These results appear to confirm a previous suggestion that heavy beer drinking during pregnancy is related to decreased intrauterine growth, but should be interpreted cautiously since there are several alternative explanations for the finding. Thus, these results suggest several areas for further investigation.

The child-adolescent blood pressure study: I. Distribution of blood pressure levels in Seventh-Day-Adventist (SDA) and non-SDA children.

Distribution of systolic and diastolic blood pressures (measured with an automated blood pressure recorder) of two large groups of children-3,159 from Seventh-Day Adventist (SDA) schools and 4,681 from non-SDA schools-are reported. They boys and girls were from four different ethnic groups and attended grades one through 10 in 29 Southern California schools. The analysis of the data failed to show significant differences in mean blood pressure levels between the two groups of children at all ages, despite marked differences in life-style between the two groups, and despite the fact that adults from the two population groups have marked differences in mortality from diseases associated with elevated blood pressure. A comparison between boys and girls showed significantly higher trends in mean systolic blood pressure for boys after age 12. Inter-ethnic comparisons of blood pressure revealed that Black children of both sexes had slightly higher mean blood pressure levels at all ages.

Patterns of alcohol and cigarette use in pregnancy.

Maternal smoking and drinking have been implicated as factors in the adverse outcome of pregnancies. This California study of over 12,000 women demonstrates that a large proportion of them smoke or drink during pregnancy. Drinking habits appear to be associated with age, ethnicity, martial status, income, education, church attendance, and prenatal care, but not with gestational age, breast-feeding, or self-reported health. Smoking shows associations with income and education. Drinking and smoking are closely interrelated, showing strikingly parallel associations with such factors as use of caffeine or illicit drugs. Subgroups of pregnant women who exhibit difference drinking habits were found not comparable on certain other characteristics which potentially influence the health of neonates. The importance is reemphasized of utilizing large populations, adjusting for confounding variables, and paying particular attention to smoking habits. Forthcoming multivariate analyses of the data set should disentangle effects of the confounding variables.

Mortality among California Seventh-Day Adventists for selected cancer sites.

In previous reports concerning cancer among Seventh-Day Adventists (SDA), comparisons were made only with the general population. This report compared California SDA to a sample of non-SDA who were demographically similar to SDA. The study consisted of 17 years of follow-up (1960--76) on 22,940 white California SDA and 13 years of follow-up (1960--72) on 112,725 white California non-SDA. Both groups completed the same base-line questionnaire in 1960. Deaths were ascertained by annual contacts with each study member and by computer-assisted record linkage with the California State death certificate file. Results indicated that, with the exception of colon-rectal cancer and smoking-related cancers, the difference in risk of fatal cancer between SDA and non-SDA was substantially reduced when SDA were compared with a more socioeconomically similar population. The persistence of the low risk for colon-rectal cancer can probably be attributed to some aspect of the diet or life-style of the SDA.

Influence of selection versus lifestyle on risk of fatal cancer and cardiovascular disease among Seventh-day Adventists.

PIP: The authors examine the influence of selection versus life-style on mortality from various causes for a population of 23,000 California Seventh-Day Adventists. The data are compared with data from a control group of 112,726 other Californians. The selective factors considered include education, occupation, and marital status^ieng

Coronary heart disease mortality among Seventh-Day Adventists with differing dietary habits: a preliminary report.

Seventh-Day Adventists (SDAs) are a conservative religious denomination who abstain from tobacco and alcohol; approximately one-half follow a lacto-ovo-vegetarian diet. In this 6-year prospective study of 24,044 California SDAs age 35 and over, coronary heart disease (CHD) mortality rates for ages 35 to 64 and 65+ are 28% and 50% respectively, of the rates for the same age groups of the total California population. This reduced risk of CHD mortality among SDAs is partially due to abstinence from smoking; however, at least half the low risk among SDAs is likely attributable to other characteristics of the SDA lifestyle. The risk of fatal CHD among nonvegetarian SDA males, ages 35 to 64, is three times greater than vegetarian SDA males of comparable age (P less than 0.01), suggesting that the SDA diet may account for a large share of their low risk. This differential was much smaller for older SDA males and SDA females. Although the differential in risk of fatal CHD for male nonvegetarians versus vegetarians may be partially accounted for by other CHD risk factors, which are more frequent among nonvegetarians, a significant differential persists after adjustment for each of six other CHD risk factors.

Rationale and methods for an epidemiologic study of cancer among Seventh-Day Adventists.

Considerable evidence was found that Adventists are a low-risk population to develop cancer of many sites. Adventists have numerous unique life-style and dietary habits with great variability within the population in adherence to these practices as well as considerable variation in duration of exposure to these characteristics. Thus this study population will likely be extremely productive in identifying dietary habits or other life-style characteristics that are etiologically related to various cancer sites.