WEDNESDAY, Feb. 9 (HealthDay News) -- Diet soda fans who drink
the beverages every day may be cutting down on calories, but they
also might be boosting their risk of stroke, new research
"In our study, we saw a significant increased risk among those who drank diet soda daily and not regular soda," said Hannah Gardener, an epidemiologist at the University of Miami Miller School of Medicine, who was slated to present her research Wednesday at the International Stroke Conference 2011 in Los Angeles.
Why the link? "It's unknown at this point," she said.
Stroke is the third leading cause of death, behind heart disease
and cancer, in the United States. More than 137,000 people a year
die from stroke, according to the American Stroke Association.
Previous research by others has found that those who drank more
than one soft drink a day, whether regular or diet, were more
likely than non-drinkers to have metabolic syndrome, a cluster of
risk factors including high blood pressure, elevated triglycerides
(blood fats), low levels of good cholesterol, high fasting blood
sugar and large waists. Metabolic syndrome, in turn, raises the
risk of diabetes and cardiovascular disease, experts agree.
Gardener and her colleagues evaluated the soda habits of 2,564
people enrolled in the large Northern Manhattan Study (NOMAS) to
see if there was an association, if any, with stroke. The
participants were 69 years of age, on average, and completed food
questionnaires about the type of soda they drank and how often.
During the average nine-year follow-up, 559 vascular events
occurred, including strokes caused by hemorrhage and those caused
by clots, known as ischemic strokes.
The researchers controlled for such factors as age, gender,
ethnicity, physical activity, calorie intake, smoking and alcohol
drinking habits and still found that those who drank diet soda
daily -- compared to those who drank no soda -- were 61 percent
more likely to have a vascular event.
The researchers then controlled for the presence of metabolic
syndrome, vascular disease in the limbs and heart disease history;
the link still held, albeit at 48 percent.
While the study found a possible association between diet soda
and stroke risk, it did not demonstrate a cause and effect. And
experts note that research presented at meetings has not been
subjected to the same type of rigorous scrutiny given to research
published in peer-reviewed medical journals.
"If our study is replicated," Gardener said, "it would suggest diet soda is not optimal."
Dr. Patrick Lyden, chief of neurology at Cedars-Sinai Medical
Center in Los Angeles, reviewed the findings but was not involved
in the research. "My first thought was, 'The correlation has to be
accidental,'" he said.
But he said the science in the study looks sound. "There still
could be some sort of accidental correlation," he said. What to do?
"Wait for repeated studies to show a risk and in the meantime, all
things in moderation."
He tells his patients to avoid soda, whether diet or regular, on
a daily basis. "An occasional soda never hurt anybody," he said.
"Once or twice a week to me seems to be rational."
In a separate study, Gardener also found high salt intake was
linked to a higher risk of stroke. Using the same data, she looked
at 2,657 participants of NOMAS, evaluating their salt intake and
following them for nearly 10 years.
During that time, 187 ischemic strokes occurred. Those who
consumed more than 4,000 milligrams a day of sodium had more than
double the risk of ischemic stroke than those who consumed less
than 1,500 milligrams a day.
How much salt is ideal? The American Heart Association
recommends less than 1,500 milligrams a day. The current U.S.
Dietary Guidelines for Americans recommends eating less than 2,300
milligrams a day and even less -- 1,500 milligrams a day -- for
those who are 51 and older and certain other people. Among those
who should stop at 1,500 milligrams of salt a day are blacks and
people with hypertension, diabetes or chronic kidney disease.
To learn more about strokes, visit the
American Heart Association.
Please be aware that this information is provided to supplement the care provided by your physician. It is neither intended nor implied to be a substitute for professional medical advice. CALL YOUR HEALTHCARE PROVIDER IMMEDIATELY IF YOU THINK YOU MAY HAVE A MEDICAL EMERGENCY. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with any questions you may have regarding a medical condition.
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