Yo-yo dieting ‘increases risk of heart attack and stroke’

Fluctuations in weight, blood pressure, cholesterol and blood sugar levels may be associated with a higher risk of heart attack and stroke, according to new research published in the journal Circulation.

Compared to people who had stable measurements over a period of five years, those with the highest amount of variability (in the upper 25 per cent) were 127 per cent more likely to die, 43 per cent more likely to have a heart attack and 41 per cent more likely to have a stroke.

Using data from the Korean National Health Insurance system, researchers examined data on 6,748,773 people who had no previous heart attacks and were free of diabetes, high blood pressure, or high cholesterol at the beginning of the study.

Because high variability could result from either positive or negative changes, the researchers looked separately at the effect of variability in participants who were more than 5 per cent improved or worsened on each measurement. In both the improved and the worsened groups, high variability was associated with a significantly higher risk of death.

The study’s senior author, Seung-Hwan Lee, said: ‘Healthcare providers should pay attention to the variability in measurements of a patient’s blood pressure, cholesterol and glucose levels as well as body weight. Trying to stabilise these measurements may be an important step in helping them improve their health.’

The study was observational, which means that it cannot prove a cause-and-effect relationship between high variability and the risk of heart attacks, strokes or death from any cause. The study also did not delve into the reasons behind the fluctuations in the participants’ risk factor measurements.

‘It is not certain whether these results from Korea would apply to the United States. However, several previous studies on variability were performed in other populations, suggesting that it is likely to be a common phenomenon,’ Lee said.