Having a Sibling with Heart
Disease Significantly Raises Personal Heart Disease
Risk
Having a sibling with a history of cardiovascular disease
carries the same or greater risk as having a parent
with a history of the disease, according to a new
report from the long-standing Framingham Heart Study
conducted by the National Heart, Lung, and Blood Institute
(NHLBI), a part of the National Institutes of Health
(NIH). Personal risk of having a cardiovascular event,
such as a heart attack, stroke, or peripheral artery
disease, may be raised by as much as 45 percent in
middle-aged people whose brother or sister has had
such an event.
The study appears in the December 28, 2005, edition
of the Journal of the American Medical Association.
Even when data was adjusted for the fact that siblings
may have similar lifestyle-related risk factors and
may be of similar ages, the risk associated with having
a sibling with cardiovascular disease remained high.
Physicians determine relative risk for cardiovascular
disease by evaluating known risk factors: family history
of heart disease, age, high blood pressure, high cholesterol,
overweight, current or former smoking, physical inactivity,
and diabetes. While having a parent or sibling with
heart disease has long been suggested to increase
risk, this study shows that having a sibling with
heart disease is a significant risk factor independent
of other measures.
“This study illustrates that even people who
are not at high risk based on their own health status
should talk to their doctors about the history of
heart disease in their families, among siblings as
well as parents, and ask what they can do to prevent
a heart attack or stroke,” said NHLBI Director
Elizabeth G. Nabel, M.D.
Researchers evaluated siblings from among 1188 men
and 1287 women, all participants in the Framingham
Heart Study. Participants were at least 30 years old
at the time of a baseline examination, and were followed
for eight years for the occurrence of a cardiovascular
disease event.
“We determined that one’s risk from a sibling
with a cardiovascular disease event remains elevated
after taking into account age and other risk factors
that may cluster within families. The risk may be
even higher than the risk related to having a parent
with cardiovascular disease,” said Joanne Murabito,
MD, ScM, of Boston University, the study’s lead
author. “The risk from a sibling with cardiovascular
disease is significant even in persons with borderline
elevated levels of total cholesterol, levels at which
physicians are often undecided about medication treatment.”
The Framingham Study is one of the first studies to
take an independent, unbiased look at sibling risk.
Unlike other studies of family history, which relied
on often-unreliable participant recall, this study
evaluated independent data from families within the
57-year-long observational study. Participants in
this evaluation were from the study’s Offspring
group, the adult children of the original participants
who first enrolled in the 1940s and 1950s.
“Our findings suggests that taking an accurate
family history should be a crucial part of every physician’s
method of assessing heart disease risk, and should
go beyond a simple ‘yes’ or ‘no’
question about the presence of disease in the family,”
said Dr. Murabito.
Patients should make the effort to collect medical
history information from their siblings and parents
and make sure to inform their siblings if they have
a cardiovascular disease event such as a heart attack
or stroke, she added.
“We believe that the reasons behind the strong
association of risk between siblings are environmental
as well as genetic. In addition to sharing the same
genetic makeup, siblings may share similar dietary
habits and physical activity patterns in their early
years while living in the same household. These habits
may continue on into adulthood when genetic factors
begin to manifest,” said Christopher O’Donnell,
MD, MPH, associate director of NHLBI’s Framingham
Heart Study and the study senior author.
“While you can’t control your family history,
there are many things you can do to control your risk
for heart disease, including keeping your blood pressure,
cholesterol and blood sugar under control, maintaining
a healthy weight, avoiding smoking, and getting regular
physical activity, “ said Dr. O’Donnell.
In May of 2004, the Framingham Heart Study research
team demonstrated that having a parent with a cardiovascular
disease history doubles personal risk of the disease.
To schedule an interview, please contact the NHLBI
Communications Office at 301-496-4236.
For more information about heart disease risk factors
and the Framingham Heart Study, visit the NHLBI Web
site at www.nhlbi.nih.gov/about/framingham/.
Information about taking a personal family history
can be found at the U.S. Surgeon General’s website
“My Family Health Portrait” (https://familyhistory.hhs.gov/).
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