Better measure of 'good cholesterol' can gauge heart attack and stroke
risk in some populations
Still no existing measures to accurately predict heart attacks in black
people

Date:
June 22, 2020
Source:
UT Southwestern Medical Center
Summary:
For decades, high-density lipoprotein (HDL) cholesterol has been
dubbed 'good cholesterol' because of its role in moving fats and
other cholesterol molecules out of artery walls. People with higher
HDL cholesterol levels tend to have lower rates of cardiovascular
disease, studies have shown.



FULL STORY ==========================================================================
For decades, high-density lipoprotein (HDL) cholesterol has been
dubbed "good cholesterol" because of its role in moving fats and other cholesterol molecules out of artery walls. People with higher HDL
cholesterol levels tend to have lower rates of cardiovascular disease,
studies have shown.


==========================================================================
Now, UT Southwestern scientists have analyzed data on more than 15,000
people to better understand the association between HDL cholesterol,
heart attacks, and strokes in diverse populations. They found that the
number of HDL particles, a little-used measurement of HDL, is a more
reliable predictor of heart attack and stroke risk than the standard
HDL cholesterol metric.

Moreover, they found that among black people, neither HDL measurement
was significantly associated with heart attack.

"Previous studies have looked at HDL levels in the population as a whole,"
says Anand Rohatgi, M.D., an associate professor of internal medicine
at UTSW. "But we know that sometimes biology differs by gender and race,
so we thought it was important to separately tease apart what's happening
in those populations, as well as how HDL is associated with stroke, which
has been understudied." According to the Centers for Disease Control and Prevention, heart disease is the leading cause of death in the U.S. More
than 12 percent of adults in the U.S. have high total cholesterol levels,
and more than 18 percent have what's currently considered low levels of
HDL cholesterol.

Cholesterol is a waxy substance that is used by the body to make
hormones and keep cells functioning properly. But when low-density
lipoprotein (LDL) cholesterol levels are too high, cholesterol can
accumulate inside blood vessels, forming deposits called plaques. These
plaques can eventually lead to blood vessel blockages that cause heart
attacks or strokes. HDL cholesterol helps remove cholesterol from blood vessels. But recent studies have come to mixed conclusions about the association between HDL cholesterol levels and health outcomes.

For the new paper, published in the journal Circulation, Rohatgi and his colleagues pooled together information on people who had participated in
four large, nationwide studies -- the Dallas Heart Study, Atherosclerosis
Risk in Communities study, Multi-Ethnic Study of Atherosclerosis, and
the Prevention of Renal and Vascular Endstage Disease study. In all,
the studies included 15,784 people followed over an average of 8 to 12
years. Of the participants, 54 percent were male, 22 percent were black,
and their average age was 56 years.



==========================================================================
"By combining all these large existing cohorts, we had enough numbers
to look at these populations that had been understudied in the past,"
says Kavisha Singh, M.D., a research fellow in cardiology at UTSW and
first author of the new study.

In addition, the data included two different measurements of HDL: HDL-P
levels tally how many particles of HDL are circulating in the blood. HDL-C levels, the standard test, instead quantify how much total HDL cholesterol
is inside those particles. Since the number of HDL particles may vary
with regards to how much cholesterol they contain, the two measurements
can be quite different and are only moderately correlated.

In the study, people with the highest HDL-P levels, above 37 mmol/L,
had a 37 percent lower risk of heart attack and a 34 percent lower
risk of stroke than those who had the lowest HDL-P levels. In women,
this association was stronger -- those with the highest HDL-P levels
had a 49 percent reduction in heart attacks and 46 percent reduction in
stroke. While HDL-C predicted heart attack risk in the overall pool of
people as well as in women, it was not associated with stroke.

When the researchers homed in on black participants, the results were
different -- neither HDL-C nor HDL-P was linked to a black person's risk
of heart attack.

"If you're white, low HDL cholesterol is still a powerful predictor
of heart attack and stroke risk, and that has not changed," says
Rohatgi. "But if you're not white, it's not that straightforward."
A better understanding of how HDL can help predict disease, and how
that association varies among populations, is vital to lowering rates
of cardiovascular disease, the researchers say.

"These risk markers are really relevant in everyday primary care and cardiology," says Singh. "Doctors use cholesterol levels to make decisions
like whether a patient goes on medication or not." The team is planning
future studies on the functionality of HDL particles among black people,
how HDL-P may be used clinically, and whether HDL-P might be associated
with specific subtypes of strokes.


========================================================================== Story Source: Materials provided by UT_Southwestern_Medical_Center. Note: Content may be edited for style and length.


========================================================================== Journal Reference:
1. Kavisha Singh, Alvin Chandra, Thomas Sperry, Parag H. Joshi,
Amit Khera,
Salim S. Virani, Christie M. Ballantyne, James D. Otvos, Robin P. F.

Dullaart, Eke G. Gruppen, Margery A. Connelly, Colby R. Ayers, Anand
Rohatgi. Associations Between HDL Particles and Ischemic Events
by Vascular Domain, Gender, and Ethnicity: A Pooled Cohort Analysis.

Circulation, 2020; DOI: 10.1161/CIRCULATIONAHA.120.045713 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2020/06/200622132957.htm

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