Everyone's heard the litany: High concentrations of cholesterol in the blood raise a person's risk of dying from heart attacks and stroke. A new study suggests, however, that this assessment may need a qualification -- notably, it may not apply to men and women who survive into their late eighties.
For them, a new rule seems to emerge: The higher an individual's cholesterol, the longer he or she will live. in the very senior citizens studied, the risk of dying during a 10-year study fell by 15 percent for each additional 39 milligrams of cholesterol in a deciliter (dl) of blood.
"This finding was a surprise," acknowledges study leader Annelies W.E. Weverling-Rijnsburger of Leiden University Medical Centre in the Netherlands.
As part of an ongoing study of Leiden elders, Weverling-Rijnsburger's team measured total cholesterol in 724 men and women, all of whom were 85 or older in 1986. Some 24 percent had less than 200 mg/dl, an amount usually considered healthy Another 48 percent had moderately high concentrations (up to 250 mg/dl), and the rest were even higher.
By last year, 88 percent of the participants in the study had died. Contrary to standard wisdom, heart disease, the predominant killer, claimed roughly the same proportion of victims from each cholesterol group, the Dutch researchers report in the Oct. 18 Lancet. By way of explanation, Weverling-Rijnsburger speculates that persons especially susceptible to cholesterol's heart risks die at a younger age.
In some people, moreover, low cholesterol may be a result of chronic, life-threatening disease, says Daniel Levy, director of the long-running Framingham (Mass.) Heart Study. In the Framingham population, he says, such disease -- especially unrecognized cancer -- appears to explain why "above age 50, we find a very poor relationship between cholesterol levels and mortality."
Among the Leiden seniors, the low-cholesterol group experienced the highest rate of death from cancer and infections, while the high-cholesterol group suffered least from such problems -- largely explaining that group's generally longer survival.
The infectious disease component of these findings appears to be consistent with data from studies of animals reported last year by Jos W.M. van der Meer and his colleagues at University Hospital in Nijmegen, the Netherlands. Normal mice died when injected with large quantities of pneumonia-causing bacteria. Animals with what would normally be considered highly elevated low-density lipoprotein (LDL) cholesterol-- the so-called bad cholesterol -- survived the same load of germs. One reason, van der Meer says, is that their LDLs bound the poison produced by the bacteria, facilitating its "detoxification."
COPYRIGHT 1997 Science Service, Inc.
COPYRIGHT 2004 Gale Group
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