U.S. researchers writing in The American Journal of Cardiology have
found better levels of "good cholesterol" and other markers of heart
health in the blood of middle-aged study subjects with a sunny outlook
on life.
At least some of the connection between optimism and
blood lipids in the new study appeared to result from the optimists'
tendency to have a healthy body weight and a "prudent" diet, according
to researchers.
"It is one additional piece of evidence suggesting that our
psychological health and physical health are intertwined, and that
viewing the world optimistically may have some tangible benefits for our
health," said lead author Julia Boehm, a research fellow at the Harvard
School of Public Health.
Previous research by Boehm and her
colleagues had shown a link between optimism and lowered heart attack
risk, so they decided to look at whether there was an independent
connection between optimistic or pessimistic outlooks and cholesterol,
which is known to play a role in heart attack risk.
The group analyzed data from the Midlife in the United States study,
which included phone interviews and lab tests for 990 people aged 40 to
70.
Based on the interviews, participants' levels of optimism
were rated on a scale from 6 to 30 depending on their agreement or
disagreement with statements like "in uncertain times I usually expect
the best."
People with higher optimism scores also had more
high-density lipoprotein (HDL), the desirable form of cholesterol that
is believed to protect against heart disease. They also had lower levels
of triglycerides, the fatty molecules involved in hardening of the
arteries.
There was no connection between optimism and total cholesterol
levels, or to low-density lipoproteins (LDL), the "bad" cholesterol. Fore every increase of 5 points on the optimism scale, however, HDL in the blood increased by 1 milligram per deciliter.
That
same HDL increase would translated to a three percent reduction in the
risk for heart disease, experts said. For comparison, regular exercise
can decrease heart disease risk by six percent.
"Honestly, I'm
not surprised, this is what I expect," said Franz Messerli, a
cardiologist at St. Luke's-Roosevelt Hospital in New York, who was not
involved in the study.
It's still impossible to say whether
optimism causes a change in cholesterol, or cholesterol influences
outlook, or both are subject to some third variable, Messerli said.
Boehm's
group did try to account for other influences, and when they factored
in lifestyles, including diet and alcohol consumption, and body weight -
the link between optimism and blood fats became weaker.
That
suggests that optimists' tendency to have healthier lifestyles and
weight may explain "in part" the differences in their blood lipids,
researchers said.
Conversely, the risk of heart attack and stroke
goes up in depressed people, Messerli said. "But nobody has shown the
opposite, that all of a sudden if you go from a pessimist to an optimist
your risk goes down," he added.
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