Biological Aging Predicts Heart Attack
People who age fast -- as measured by DNA shortening -- have a higher heart disease risk. Statin drugs may help, a study suggests.
Jan. 11, 2007 -- People who age fast -- as measured by DNA shortening --
have a higher heart disease
risk. Statin drugs may help, a Lancet study suggests.
Every time a cell in the body replicates, the DNA string (the telomere) at
one end of the chromosome gets shorter. When it gets too short, the cell
Current scientific thought holds that this process is directly related to
aging. Telomere shortening
happens at different rates for different people. This suggests that our
chronological age (the number of years since our birth) is different from our
biological age (as measured by telomere shortening).
Does our "biological age" really predict death and disease? Scott W.
Brouilette, PhD, and colleagues have previously shown that telomere length in
people who have heart attacks before age 50 and in people who are candidates
for triple bypass surgery tends to be shorter than telomere length in healthy
people of the same age and sex.
In their current study, the researchers looked at people enrolled in a
clinical trial of the cholesterol-lowering drug Pravachol. Over five years, 484
patients developed heart disease. The researchers compared their telomere
length in white blood cell DNA to that of 1,058 matched people who remained
free of heart disease.
Sure enough, those who got heart disease had telomere lengths similar to
those in the comparison group who were six years older. Study participants in
the top third of telomere length were about 50% less likely to have heart
disease as those in the middle or lower third in telomere length.
"Our findings lend support to the hypothesis that premature biological
aging might contribute to the risk of coronary heart disease," Brouilette
and colleagues suggest in the Jan. 13 issue of The Lancet.
Oddly, the heart risk seen with shorter telomere length did not increase
beyond a certain point.
"This finding suggests that, especially with increasing age, there could
be a threshold beyond which further shortening of telomeres does not confer
additional risk," the researchers theorize.
Do Statins Slow Biological Aging?
Interestingly, Pravachol -- one of the "statin" family of
cholesterol-lowering drugs -- dramatically lowered the heart disease risk of
people with shorter telomeres. But the drug seemed to have little effect on
heart disease risk in people with the longest telomeres.
Brouilette and colleagues suggest that statin drugs may slow biological
aging not by lowering cholesterol but by increasing blood levels of a molecule
that stabilizes telomeres.
The researchers suggest that by measuring telomere length, doctors could
identify those patients most likely to benefit from statin treatment.
However, a Lancet editorial appearing alongside the study casts doubt on
Ioakim Spyridopoulos, MD, and Stefanie Dimmeler, PhD, of the University of
Frankfurt, Germany, agree with Brouilette and colleagues that biological aging
could contribute to heart disease risk.
But they note that different people start out life with different-length
telomeres. An individual's telomere length, they suggest, says nothing about
how fast that person is aging.
Looking at telomere length in a large number of people may provide insight
into the relationship between biological aging and disease. But they flatly
reject the idea that telomere length could predict an individual's risk of