In a 2017 study, researchers looked at the connection between fluctuating body weight and increased risk of heart attack and death in patients who have coronary artery disease (CAD). This study found that amongst people with CAD, a fluctuating body weight leads to higher rate of death and a higher risk of cardiovascular events, not even factoring in cardiovascular risk factors.
Coronary artery disease (CAD) is a condition where plaque (waxy substance) builds up along the walls of the arteries that supply the heart, restricting blood flow and therefore oxygen flow to the heart. This disease can develop over many years, but if the plaque ruptures, a blood clot can be released, which can block the artery or travel up to the brain causing a stroke. The growing plaques narrow the artery, which can lead to either a decrease in oxygenated blood travelling to the heart, causing angina, or a complete blockage of the artery, meaning no blood flow which results in a heart attack. Obesity has long been known to be a risk factor for heart disease and death, and weight loss is the treatment. But what about significant weight loss followed by weight gain, continuing in a cycle (known as weight fluctuation or variability)? The following article aims to see whether weight fluctuation affects coronary events in patients with CAD.
Previous studies have shown that in healthy people who do not have any cardiovascular disease, body weight changes do lead to increased mortality and coronary events. Current research aims to see if the connection is still there in patients with pre-existing CAD.
To further explore the association between body weight fluctuations and the risk of death and cardiovascular events, a novel study published in the New England Journal of Medicine recruited 9509 patients from the Treating to New Targets (TNT) Trial. The selected participants all had CAD, were an average age of 61.8 years old, and an average weight of 83.3kg. Two weight measurements were taken from each patient records from the TNT trial, and then their weights were recorded at 3,6 and 9 months, 1 year and every 6 months after to monitor their weight fluctuations and coronary events; this continued for 4.9 years.
Of the 9509 participants, 2091 of them experienced a coronary event during the study. An example of a coronary event is angina or a non-fatal heart attack. 2727 patients experienced cardiovascular events, e.g. heart failure or stroke, and 487 participants died. Patients whose body weight fluctuated the most, and had a greater variability between weight measurements at the time intervals, had increased risk of several events. The risk of stroke rose 136%, significantly higher than the patients whose weight changes, during the study, were not as severe. The risk of death increased 124%, whilst the risk of cardiovascular events increased by 85% compared to participants with lower weight variability.
This study had limitations in that it only used BMI as a measure for obesity in its participants, no other methods were used. BMI does not take into effect lifestyle factors and body composition, and is therefore not very accurate to be classifying people as obese in this study. This research shows that maintaining a healthy weight, not constant weight fluctuations, is the way to go to live a safer and healthier life.
In conclusion, the results of this study indicate that there IS a connection between fluctuating weight and an increased risk of death and cardiovascular events in patients with established coronary artery disease.
Written By: Eleanor Shepherd, BMedSc