Studies: Naps, mammograms, blood-sugar tests can reveal stroke risk

NEW ORLEANS -- What do mammograms, blood-sugar tests and daytime dozing have in common? All may offer clues that someone is headed for a stroke, new studies suggest.

Higher stroke risk was seen in women with artery buildups accidentally revealed by mammograms, in nondiabetics starting to have insulin problems and in older people who nod off a lot.

People should not panic if they have one of these signs. But if grandma falls asleep in front of the TV all the time, it may be worth checking to see if she has a sleep disorder raising her risk of stroke, doctors say.

Likewise, a test that rules out breast cancer may give a valuable clue to heart disease and stroke risks -- if radiologists report the findings to women and their doctors for follow-up.

"You're getting information in two important areas," but people often focus on just the cancer risk, said Dr. Philip Gorelick, neurology chief at the University of Illinois in Chicago. He is chairman of the International Stroke Conference, a medical meeting in New Orleans where the studies were presented Thursday.

Daytime sleepiness

Daytime drowsiness may be due to nighttime sleep apnea, a common condition where people briefly stop breathing, causing spikes in blood pressure as they startle awake. Snoring can be a sign, but doesn't always mean trouble -- except for others trying to sleep.

"It's not healthy because you're not staying in your normal sleep pattern. You're waking up many times in the night and in the daytime are tired," Gorelick explained.

Columbia University researchers led by Bernadette Boden-Albala found that a simple scoring system to evaluate daytime dozing strongly predicted stroke risk. They asked 2,100 people, average age 73, how often they nodded off during specific situations during the day -- watching TV, reading, sitting and talking to someone, sitting in traffic, or sitting quietly after lunch.

In the next two years, 40 had strokes and 127 had other blood vessel-related problems such as heart attacks or blood clots in the lungs.

The odds of having a stroke were nearly five times greater among heavy dozers, and nearly three times greater among occasional dozers, compared with people who rarely nodded off. The chances of other vessel-related problems were higher, too.

Mammography study

The mammography study was led by medical student Amy Loden and Dr. Paul Dale of the University of Missouri Medical School in Columbia, Mo. They studied calcium deposits in the walls of arteries that supply the breasts, which are different from the calcifications in breast tissue that can signal the presence of a tumor.

He previously published studies tying these artery deposits to a higher risk of heart disease. In the new study, he and fellow researchers found these deposits in 11 percent of roughly 800 women having routine mammograms at their hospital.

Next, they looked at the mammograms of 204 stroke patients and found the deposits in 56 percent of them -- five times more often. Greater stroke risk was seen in women of all ages with the deposits, but especially among those in their forties and fifties.

"We're not saying just because you have these you're going to have a stroke -- it's just identifying women at risk," Dale said.

Blood-sugar testing

The third study looked at clues of stroke risk from a different test -- HOMA, a ratio of blood-sugar and insulin levels measured after fasting. High scores signal insulin resistance, a condition where the body is not able to effectively use that hormone to turn food into energy, raising the risk of diabetes.

Dr. Tatjana Rundek at the University of Miami led a study of 1,735 nondiabetic people, average age 68, participating in a long-running study of stroke risk in New York, funded by the federal government.

One-fourth had high HOMA scores, and in the next seven years, they had twice the risk of stroke compared to those with low scores.