Extensive studies of coronary heart disease have been conducted among Adventists, both in the United States and abroad. However, the Adventist Health Study has gone an important step further in collecting data on both fatal and non-fatal cases of coronary heart disease.
Early Heart Disease Studies
For fatal cases of coronary heart disease, the older Adventist Mortality Study found that the mortality rates for Adventist men in particular were only 66 percent as compared to their non-Adventist counterparts. When compared only to non-smoking non-Adventists, the figure rose to 76 percent. Differences for women were less impressive.
Studies of risk factors associated with coronary heart disease in Adventists have also been done since the early 1950s. Typically, serum cholesterol levels have been shown to be significantly lower for Adventists when compared to non-Adventists. Actual levels have generally been at least 10 to 30 milligrams per deciliter lower.
Recent Heart Disease Studies
More recently, Dr. Fraser and his colleagues looked at 160 randomly selected, middle-aged Adventist men and a similarly-aged non-Adventist group of neighbors in Southern California. This was one of only a few studies to look at lipoprotein subfractions in Adventists. Their findings:
The HDL cholesterols were 42.3 in Adventists as compared to 46 in non Adventists.
The LDL cholesterols were 125.1 in Adventists and 134.0 in non-Adventists.
Though the ratio between the HDL and LDL levels was similar, the differences in levels of the component lipoproteins were highly statistically significant.
It is noted that lower levels of HDL cholesterol are characteristic of populations with lower fat intakes. The risk meaning of this lower level in vegetarians is unknown. Some controversy surrounds the risk factor of high blood pressure in vegetarians. However, both Adventist and non-Adventist vegetarians probably experience a reduction of 4 to 5 millimeters systolic and 2 to 3 millimeters diastolic, considered to be a relatively minor difference.
The risk factor of little or no exercise has not been studied to any great extent in Adventists. However, the Southern California study included the following question: "How many times each week do you exercise enough to provoke a sweat?" In Adventists, the responses averaged 2.38 times per week; for non-Adventists, 1.5 times per week (one-third less). In this case, the difference in exercise habits was highly statistically significant. The risk factor of obesity has also received very little attention in Adventists. However, in the previously mentioned study, Quetelet index of obesity in Adventists showed very little difference from their non-Adventist neighbors.
Risk Factors in the Adventist Population
It has been argued that Adventist populations are so unique in their lifestyles that none of the findings can be accurately applied to general non-Adventist populations. To counter that argument, researchers investigated associations between heart disease and factors such as age, sex, diabetes mellitus, hypertension, smoking, physical activity and obesity in the Adventist Health Study population. Using several statistical models, they found these risk factors had the same role in predicting heart disease among Adventists as had been repeatedly shown in non-Adventist populations.
Other Risk Factor Findings
Within the Adventist population, it was noted that heart attack risks:
- Doubled for diabetic Adventists.
- Doubled for obese Adventists.
- Tripled for diabetic Adventists.
- Elevated substantially among current and past smokers.
When comparing the sexes, heart attack risks were similar to those of non-Adventist populations. The risk was 2.87 times higher for men than women, with the risk of fatal coronary heart attack 1.90 times higher than women.
Diet and Heart Disease
Answers to the dietary questions in the survey also provided some new findings about the Adventist population. To begin, there were some surprising findings:
21 percent admitted they consumed beef more than twice a week. 10 percent ate fish as often as once a week. 35 percent admitted to coffee use.
Others were more expected:
- 77 percent consumed primarily whole wheat bread.
- 66 percent ate nuts at least once a week.
- 24 percent eating nuts more than four times a week.
- 81 percent ate fruit at least once a day.
- 49 percent eating fruit at least three times a day.
The effects of diet on the risk of coronary heart disease (CHD) are of increasing interest in heart disease research. In six-year follow-up survey, researchers found:
- 134 new cases of definite non-fatal CHD
- 260 new cases of fatal CHD
In these new cases, no history of heart disease existed at the beginning of the study.
Other Diet and Heart Disease Findings
- Consuming beef may increase the risk of fatal coronary heart disease for men. Adventist men who ate beef more than two times a week experienced a significant increase in fatal CHD.
- By contrast, beef consumption did not clearly change the risk of heart disease in women.
- Eating whole wheat bread can protect against heart disease. Individuals who consumed mainly whole wheat bread had a relative risk of 59 percent for non-fatal coronary heart disease, and 89 percent for fatal heart disease, compared to those who mainly ate white bread.