Researchers found that people with coronary heart disease who had experienced large fluctuations in weight over an average of 4.7 years were at much higher risk of heart attack, stroke, and death than people who experienced little change in body weight.
Lead study author Dr. Sripal Bangalore, of the Cardiovascular Clinical Research Center at NYU Langone Medical Center in New York, and colleagues recently reported their results in the New England Journal of Medicine.
Yo-yo dieting - also known as "weight cycling" or the "yo-yo effect" - is defined as repeated cycles of weight loss and weight gain.
A number of studies have documented the possible health risks of yo-yo dieting. One study reported by Medical News Today last year, for example, uncovered a link between weight cycling and greater risk of death from heart disease.
The new research from Dr. Bangalore and colleagues builds on those findings, revealing how yo-yo dieting may impact the health of individuals who have pre-existing coronary heart disease.
Coronary heart disease (CHD) - also referred to as coronary artery disease - is the most common form of heart disease among men and women in the United States. Each year, the condition kills more than 370,000 people in the country.
CHD is characterized by atherosclerosis - the buildup of plaque in the coronary arteries, which are those that supply the heart with oxygen-rich blood. This plaque buildup may block the blood supply to the heart, which can lead to angina (severe chest pain) or heart attack.
Largest weight fluctuations linked to 124 percent more deaths
For their study, Dr. Bangalore and colleagues analyzed the data of 9,509 men and women with CHD aged between 35 and 75 years.
As well as CHD, all subjects had high cholesterol levels and a history of other heart problems. Around half of the participants were undergoing intensive cholesterol-lowering therapy.
Over a median follow-up period of 4.7 years, participants were monitored for changes in body weight, and the researchers looked at whether these changes were associated with poorer outcomes.
Subjects with the greatest changes in body weight experienced a weight fluctuation of up to 3.9 kilograms (around 8.6 pounds) during follow-up, while those with the smallest body weight changes had weight fluctuations of 0.9 kilograms (around 2 pounds).
The team found that for individuals who were overweight or obese at study baseline, there were 117 percent more heart attacks, 124 percent more deaths, and 136 percent more strokes among those who experienced the largest changes in body weight, compared with those who experienced the smallest body weight changes.
Additionally, the researchers found a link between changes in body weight and increased risk of new-onset diabetes.
These findings remained after accounting for participants' average body weight and the presence of common risk factors for heart disease, the authors note.
Findings raise concerns about weight fluctuation in people with CHD
Dr. Bangalore and team say that their study is only observational, so it is unable to prove cause-and-effect between yo-yo dieting and increased risk of heart attack, stroke, and death among people with CHD.
Additionally, the authors point to a number of limitations. For example, they were unable to pinpoint precisely why subjects lost or gained weight during follow-up. As such, it is possible that pre-existing heart problems led to weight changes.
Still, the researchers believe that their results warrant further investigation.
"Our findings suggest that we need to be concerned about weight fluctuation in this group that is already at high risk due to coronary disease.
Even though this analysis was not designed to find out the causes of increased risk with body weight fluctuations, we need to examine how we can help Americans keep weight off, rather than having it go up and down."
Dr. Sripal Bangalore