Jan W. Kuzma

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.

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.

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.

Significant Determinants of Susceptibility to Alcohol Teratogenicity

Typically, the rate of abusive drinking during pregnancy considerably exceeds the rates of fetal alcohol syndrome (FAS) and alcohol-related birth defects, suggesting that other factors may modify the impact of alcohol on the developing organism. Data in the literature supporting this susceptibility hypothesis are sparse. In this paper, two studies in different samples, using different analytic strategies to examine susceptibility to different adverse outcomes are presented. Among 176 pregnancies in which lowered birth weight for gestational age was detected as an effect attributable to frequent beer drinking, 27 infants weighted less than 2,700 grams and 149 weighed more. Using discriminant analysis to contrast these groups, lowered birth weight for gestational age was associated with black race and lower maternal weight and weight gain. The effects of these factors were additive with that of persistent alcohol exposure; no interactions were detected, but pregnancies with risks in addition to alcohol were more likely to yield growth-retarded infants. In a second study, pregnancies resulting in 25 FAS cases were contrasted with 50 controls. A four-factor model accounted for nearly two-thirds of the explainable variance in the occurrence of FAS. Adjusted for frequency of maternal drinking, chronic alcohol problems and parity, there was a sevenfold increase in risk for FAS among black infants. The findings from both studies are consistent with the susceptibility hypothesis and have potentially important implications for public health and clinical approaches to prevention, as well as for future research.

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 Societys 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.

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 Coxs 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.

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/cunent) averaged 0.48, 0.41, and 0.62, respectively. A crude difference of 2.0 between cases and controls (p < 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 = 0.7) 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 < 0.001), primarily because of changes in dietary habits

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

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.

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.