Mortality studies of Seventh-day Adventists
The first major study of Adventists, begun in 1958, has become known as the Adventist Mortality Study, a cohort or prospective study of 22,940 California Adventists. Organized at Loma Linda University, it entailed an intensive 5-year follow-up and a more informal 25-year follow-up. During the first period, a similar study was being conducted by the American Cancer Society. Both studies enrolled volunteer subjects who were relatively well-educated.
In general, the Adventist population in California tends to be more educated than the general public. However, the population for the study by the American Cancer Society was, on average, even slightly more educated than their Adventist counterparts.
The similarities between the groups were important because it has been found that individuals who volunteer for such studies tend to be healthier than the general population, and those in the upper socio-economic classes tend to have lower rates of disease overall. Thus, the Adventist Mortality Study and the American Cancer Society Study provide a reasonably fair comparison between Adventists and non-Adventists. This comparison between the two groups revealed the following results. But first, a word about p values.
P values are quoted when they are statistically significant (p<0.05). Keep in mind that the p value should not be used to prove or disprove causality. However, in a relative sense, the larger the p value, the more plausible a chance explanation becomes for the apparent association. Conversely, a very small p value provides some evidence in favor of causality.
Overall cancer mortality, comparing Adventists to their American Cancer Society counterparts, was 60 percent for Adventist men and 76 percent for Adventist women.
Comparing specific types of cancer deaths, with the non-Adventist population as the standard, lung cancer deaths among Adventists were 21 percent. Colo-rectal cancer deaths were 62 percent among Adventists.
Breast cancer death rates for Adventist women were 85 percent; prostate cancer death rates for Adventist men were 92 percent. For lymphoma or leukemia, the death rates stood at 86 percent for Adventist men and 100 percent for Adventist women.
Death from coronary heart disease among Adventist men was 66 percent; for Adventist women, it was 98 percent. Stroke death rates for Adventist men were 72 percent, compared to their non-Adventist counterparts. For Adventist women, death from stroke was 82 percent.
Comparing all causes of death among the two populations, Adventist men had a death rate of 66 percent and Adventist women had a rate of 88 percent.
Since smoking has been shown to be a major factor in causing diseases such as cancer, researchers from the Adventist Mortality Study compared the mortality rates of non-smokers from both populations. As would be expected, the mortality rates for these non-Adventists were closer to those of the Adventists. However, an advantage for the Adventists generally persisted which could now not be accounted for by differences in tobacco use. Thus, other characteristics of Adventists, apart from their non-smoking status, such as diet and perhaps social support, are also clearly important in reducing the risk of disease.
All cancer mortality among Adventists, as compared to their non-smoking non-Adventist counterparts, was 85 percent for Adventist men and 78 percent for Adventist women.
Compared to non-smoking non-Adventists, the death rate from lung cancer for Adventist men stood at 67 percent. For Adventist women, it stood at 42 percent. For colo-rectal cancer mortality, the death rate was 67 percent for Adventist men and 42 percent in Adventist women, compared to the same group of non-Adventists.
Breast cancer death rates for Adventist women were at 81 percent; prostate cancer death rates for Adventist men were at 93 percent. Lymphoma and leukemia mortality was 93 percent for Adventist men and 89 percent for Adventist women. Again, the comparison groups were made up of non-smoking non-Adventists.
Comparing death rates from coronary heart disease between non-smoking Adventists and non-Adventists, the Adventist men had a death rate of 76 percent and Adventist women a rate of 101 percent. Stroke mortality was 75 percent in Adventist men and 79 percent in Adventist women.
For all causes of death, the rates among Adventist men were at 79 percent, and for Adventist women were at 91 percent, compared to non-smoking non-Adventists.
Studies of Adventist mortality rates have also been conducted in other parts of the world. For instance, in 1960, the national census in Norway showed an existing population of 7,173 known Adventist nationals. Then, Drs. Hans Waaler, Peter Hjort, and later Dr. Vinjar Fønnebø were able to use information gathered by the Norwegian central office of statistics, where deaths are registered, and track the mortality of this original group of Adventists as compared to the general population. The latest reports include follow-up to 1986.
They found that Adventist men were at 82 percent of the expected death rates for the general population, and Adventist women were at 95 percent.
For deaths due to cardiovascular disease in individuals less than 75 years of age, the rates for Adventist men stood at 65 percent of expectation, and Adventist women at 90 percent. Cancer deaths for Adventist men were at 78 percent and at 94 percent of expectation for Adventist women.
Another study looked at the mortality of Dutch Adventists during the years of 1968 to 1977, using records from the church administrative offices. At that time, there were about 4,000 church members in Holland. Using the general population of the country to find expected death rates, Drs. Hans Berkel and F. deWaard then compared these to the Adventist population data.
Compared to the total expected death rate, Dutch Adventists were at 45 percent. Cancer deaths were at 50 percent of expectations. Deaths from cardiovascular diseases for Adventists were at 41 percent.
Breast cancer was at 50 percent; lung cancer at 45 percent; colo-rectal cancer at 43 percent; and stomach cancer at 59 percent.
Specifically for ischemic heart disease, the rate was 43 percent; for stroke, the rate was 54 percent. Although it has not yet been mentioned, most of these results are statistically significant, making it unlikely that the differences observed were due to random factors or mere chance.
Thus, according to these studies, it is quite evident that the Adventist lifestyle does provide some protection from cancer and other fatal diseases. However, the Adventist Mortality Study, as well as the studies in Norway, Holland, and others in Poland, Denmark, and Japan, did have a fundamental weakness: nonfatal events for various diseases were not measured.
The Adventist Mortality Study raised a number of interesting questions. What was it about the Adventist lifestyle that enabled Adventists to live longer? Would lifestyle differences among Adventists themselves produce different risks for contracting specific diseases-both fatal and nonfatal?