Pieces coming
together in Parkinson’s, Cholesterol puzzle
Newswise — In 2006,
University of North Carolina at Chapel Hill
researchers published a study that found
people with low levels of LDL cholesterol
are more likely to have Parkinson's disease
than people with high LDL levels.
But that study could
not answer the question of whether low LDL
(low-density lipoprotein) levels were
present in study participants before they
were diagnosed with Parkinson’s, or if they
developed low LDL levels after being
diagnosed.
Now a follow-up study
led by UNC researchers in collaboration with
colleagues in Virginia, Hawaii and Japan has
found that low LDL levels were present in a
group of men of Japanese ancestry long
before these men were diagnosed with
Parkinson’s.
“This finding gives us
one more piece in the puzzle about the role
of cholesterol in Parkinson’s disease,” said
Dr. Xuemei Huang, the study’s principal
investigator. Huang is also medical director
of the Movement Disorder Clinic at UNC
Hospitals and an assistant professor of
neurology in the UNC School of Medicine.
“What makes these
results especially useful is the fact that
most of the men in this study were not
taking cholesterol-lowering drugs such as
statins,” Huang said.
“This suggests that the
association between low LDL levels and
Parkinson’s exists independently from statin
use, which helps answer another important
question raised by our earlier study.”
The new study was
published online this week by the journal
Movement Disorders. Huang is the lead
author. Her co-authors include Drs. G.
Webster Ross and Helen Petrovitch, who are
both with the Pacific Health Research
Institute, the Veterans Affairs Pacific
Islands Health Care System and the
University of Hawaii; Dr. Robert D. Abbott
of the University of Virginia and Shiga
University in Japan; and Dr. Richard B.
Mailman, a professor of psychiatry and
pharmacology at the UNC School of Medicine.
Low levels of LDL
cholesterol are clearly associated with good
cardiovascular health. Huang’s research adds
to a growing literature indicating that
people with low LDL may be at greater risk
for developing Parkinson’s.
“Our study again shows
an association between low cholesterol and
the risk of Parkinson’s disease, but we have
not shown cause and effect,” Huang said.
“People taking statins for valid medical
reasons should not stop simply to avoid
Parkinson’s.”
For this prospective
study, fasting lipids were measured from
1991 to 1993 in a group of 3,233 men of
Japanese ancestry who took part in a
long-running study called the Honolulu-Asia
Aging Study.
These data were
collected before statin therapy for lowering
cholesterol was widely available. When
followed for about ten years, the incidence
of Parkinson’s disease increased with
decreasing levels of LDL cholesterol.
After adjusting their
statistical analysis for age, smoking,
coffee intake and other factors, the
researchers calculated that the relative
odds of Parkinson’s for men with lower LDL
levels (85 milligrams per deciliter) was
about twice that of those with higher LDL
levels (135 milligrams per deciliter).
They concluded that
this study supports the hypothesis that low
LDL levels are associated with an increased
future risk of Parkinson’s.
Huang said more
research is needed to confirm these
findings, with logical next steps including
conducting studies with larger sample sizes
and that include women and
African-Americans.
The paper on the study,
titled “Low LDL cholesterol and increased
risk of Parkinson's disease: Prospective
results from Honolulu-Asia Aging Study,” can
be found at
http://www3.interscience.wiley.com/journal/77502481/issue.
