"Yo-yo" cardio readings may signal subsequent health risks

If your weight, blood pressure, cholesterol or blood sugar fluctuates, you are at a higher risk of heart attack, stroke and premature death than people with more stable readings, a new research suggests.

According to the study, for nearly six years of follow-up, men and women whose readings had changed the most were 127% more likely to die, 43% more likely to have a heart attack and 41% more likely to die. stroke, compared to those whose readings have remained stable.

"The variability of metabolic parameters may play a role in predicting mortality and cardiovascular outcomes," said Dr. Seung-Hwan Lee, lead author of the study, professor of endocrinology at the Faculty of Medicine at the University of Michigan. Catholic University of Korea in Seoul.

Since the study examined data from the past, it can only show a link between the variability of these readings and the risk. He can not prove that variability is the cause of the increased risk of heart attack, stroke or death, the study authors warned.

The researchers also did not examine the reasons why metabolic readings could fluctuate with time.

However, treatment strategies aimed at reducing fluctuations in these parameters should be an objective of prevention of health problems, Lee said.

These strategies could include maintaining blood pressure, cholesterol and blood glucose levels within the normal range – neither too high nor too low – and maintaining a normal weight – neither too fat nor too lean.

Dr. Gregg Fonarow, professor of cardiology at the University of California at Los Angeles, found these results interesting.

"This opens a new path for taking into account the variation of risk factors over time in estimating the risk of cardiovascular disease," he said. "Better identification of people at high and low risk could translate into better use of prevention strategies and therapies."

But further studies are needed to determine whether treatment strategies that specifically reduce the fluctuations of these parameters will reduce the risk of cardiovascular events and improve health, Fonarow said.

For the study, Lee and his colleagues used Korea's national health insurance system to collect data on more than 6.7 million people who had no heart attack, diabetes, high blood pressure, or high cholesterol level.

Between 2005 and 2012, all participants underwent at least three tests documenting weight, blood glucose, blood pressure and cholesterol.

The researchers specifically examined the effect of changes on participants whose readings increased or decreased by more than 5%. It does not matter whether the readings are better or worse – high variability itself was linked to an increased risk of death during the study period, the results showed.

Women and the elderly were more likely to have very variable parameters, the researchers said.

Lee explained that since the study was conducted in Korea, it was not certain that these results could be applied in the United States. However, other studies in different populations indicate that the link between fluctuating readings and the risk of death is common.

A specialist offered a note of caution to people who obese or overweight do not misunderstand these results.

"It's a provocative research that raises questions about excessive diets," said Dr. Byron Lee, director of labs and electrophysiology clinics at the University of California in San Francisco.

But it's far from definitive, he added. "Let's hope that obese patients do not use it as an excuse to stop trying to lose weight," Lee said.

The report was published online Oct. 1 in the journal Circulation.