The roots
of the relationship between high blood pressure and depression lie in
a mix of genetics and social factors with the family, says Karen
M. Grewen, Ph.D., of the department of psychiatry at the University of
North Carolina at Chapel Hill. “The impact of parental hypertension
on future risk [is] most likely the result of shared genes, learned behaviors,
shared environments, or various combinations.”
The study appears in the January/February issue of the journal Psychosomatic
Medicine.
Hypertension is a major risk factor not only for heart
disease but also for stroke and kidney disease. Doctors have known for
some time that
depression may presage heart-related disease and death in both healthy
people and
those who have had heart attacks. But the connection of depressive symptoms
to parents’ blood pressure status had not been documented.
How depression influences heart disease is not entirely clear. The connection
may have both behavioral and biological components. People who are depressed
may act in unhealthy ways, like smoking or not taking their medicine, which
leads to heart disease. Depression may also work more directly within the
body by triggering or inhibiting substances that endanger the heart, either
immediately or over time.
The researchers gave 314 volunteers a standard test for depression and
measured their blood pressure for 24 hours using a wearable monitor. Participants
whose mother or father or both had high blood pressure were listed as having
a family history of the disease.
Participants whose parents had hypertension had significantly
higher systolic blood pressure (the “top” number in blood pressure measurements)
and higher diastolic blood pressure (the “bottom” number).
They also had a higher body mass index, a measure of obesity, although
both groups fell into the “overweight” category.
Using the portable blood pressure monitor revealed the connection between
family history, depressive symptoms and high blood pressure, Grewen says,
while conventional, in-office measurements did not.
Another observation solidified that connection. The relationship between
depressive symptoms and blood pressure varied progressively depending on
whether one, both or neither of their parents had high blood pressure.
The association was weakest for those with no hypertensive parent, moderate
for those with one such parent and strongest for those with two parents
who had high blood pressure.
About 10 percent of the subjects with no family history had diagnosed
hypertension, as did 20 percent of those with a family history. However,
overall results were unchanged even when these subjects were excluded from
the analysis.
Because findings were the same for subjects with and without high blood
pressure, the pattern of depression and family history may precede development
of overt hypertension, Grewen says.
Future research, she says, might look at assessments of depressive symptoms
over a longer time while also considering family history of high blood
pressure. But other steps could be taken immediately to alleviate the long-term
risk posed by high blood pressure. Treating depression not only relieves
suffering and improves quality of life, but may also lower heart disease
risk.
“Depressive symptoms not considered serious enough to warrant a
mental health problem may increase blood pressure more consistently in
those with familial or genetic risk factors,” Grewen says. “Thus,
behavioral interventions that reduce depressive symptoms may be more
effective in lowering risk of hypertension in these genetically prone
people.”
This research was supported by grants from the National Institutes of
Health.
