Yo-yo dieting increases heart attack and stroke risk
Frequent fluctuations in blood pressure, glucose, cholesterol and BMI can have a serious effect on heart health and life expectancy. In a new study from South Korea, sudden changes in metabolic health parameters were associated with an increased risk of heart attacks, strokes and premature death.
The researchers analysed data from the Korean National Health Insurance System for over 6.7 million people with no history of high blood pressure, diabetes, high cholesterol or heart attacks. This is the first study to examine the variability of various metabolic parameters and cardiovascular outcomes in a large general population using a long-term validated national database.
The researchers measured each of the participants’ body weight, blood pressure, blood glucose and blood cholesterol at least three health examinations between 2005 and 2012. At the end of the study period, there were nearly 55,000 deaths, 22,000 strokes and over 21,000 heart attacks.
The study came to an end in 2015 and showed that high variability of fasting blood glucose and total cholesterol levels, systolic blood pressure, and body mass index was an independent predictor of mortality and cardiovascular events. The data showed that those whose body weight, blood pressure, sugar and cholesterol changed by more than 5% during this period were 2.3 times more likely to die an early death, and 40% more likely to suffer a heart attack or a stroke, even if the change was for the better (Table).
The researchers warn that the results are just a correlation and are not conclusive but can be used to guide further research into yo-yo dieting. Variability in metabolic parameters may have a role in predicting mortality and cardiovascular outcomes. Future treatment strategies to reduce fluctuations in metabolic parameters should be another goal to prevent adverse health outcomes.
Table: Key Hazard ratio results from the study in patients with high variability for all four parameters.
This study emphasises the need for people to maintain a stable, healthy lifestyle. The researchers encouraged healthcare professionals to pay attention to the variability in measurements of a patient’s blood pressure, cholesterol and glucose levels as well as body weight.
Kim MK, et al. Associations of variability in blood pressure, glucose and cholesterol concentrations, and body mass index with mortality and cardiovascular outcomes in the general population. Circulation 2018; published online 1 October https://www.ahajournals.org/doi/10.1161/CIRCULATIONAHA.118.034978
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