In findings that challenge traditional medical treatment of the elderly, a nine-year study of New Yorkers has found that the kinds and amounts of cholesterol in blood remain important to health and longevity even for people in their 70s and 80s.
Based on findings in the Bronx Aging Study, the researchers at the Albert Einstein College of Medicine of Yeshiva University, concluded that people in their eighth and ninth decades should be screened for cholesterol abnormalities.
In the new study, the 350 participants -- healthy men and women from 75 to 85 years old at the beginning -- were followed for an average of more than six years.
All were tested upon enrollment for the various types of fats and cholesterol in the blood and were retested one or more times during the first five years of the study.
The health status of the participants was evaluated annually and all incidents of heart attack and other heart diseases, stroke, dementia and death were recorded.
By starting with people more than 75 years old, the researchers effectively eliminated those who were presumably most sensitive to the health effects of abnormal cholesterol levels.
Such people would either have died before their 75th birthday or would have already been afflicted with one of the diseases under study and therefore would not have been eligible to participate.
The new findings suggest that even in relatively resistant adults, abnormal levels of blood fats and cholesterol continue to affect health even near the end of the life span.
During the course of the study, 81 participants suffered heart attacks, strokes or other cardiovascular disorders, 70 developed dementia and 112 died. The researchers examined the relationship between these occurrences and various measurements of blood fats and cholesterol.
In their report, published Sunday in Arteriosclerosis and Thrombosis, a journal of the American Heart Association, the researchers said that no relationship was found between total cholesterol levels and any of the disorders in question.
Nor was the onset of dementia related to any particular measurement of blood fat or cholesterol. This finding raises some question about a common belief that senility associated with aging is at least partly caused by hardening of the arteries that supply the brain.
The researchers also failed to find a link between various blood fats in the very elderly and their chances of suffering a stroke. This may have been because relatively few participants suffered a stroke.
But the Bronx researchers did find a link between certain types of cholesterol abnormalities in the elderly men and women and their risk of suffering a heart attack or other forms of cardiovascular disease.
In the elderly men, low levels of high-density lipoprotein cholesterol was found to be a "powerful predictor" of coronary heart disease, which usually shows up as a heart attack.
In the elderly women, however, HDL levels did not seem to influence their health or longevity even though it's been shown to be an important protective factor in younger women.
But those women who had high levels of another type of cholesterol, low-density lipoprotein (LDL-cholesterol), faced an increased risk of suffering a heart attack.