Men and women with large thighs have a lower risk of premature death and heart disease, a study showed today.
People whose thighs measure at least 23.6in (60cm) in circumference were less likely to develop heart disease or die early, a 12-year study of almost 3,000 men and women in Denmark found.
Professor Berit Heitmann said thigh size could be used by GPs as "an early marker to identify patients at later risk of cardiovascular disease and early mortality".
"A small thigh circumference was associated with an increased risk of cardiovascular and coronary heart diseases and total mortality in both men and women," he said.
"A threshold effect for thigh circumference was evident, with greatly increased risk of premature death below around 60cm."
He added: "The fact that more than half of the men and women aged 35-65 have thigh circumference below the threshold is worrying."
The Monica (monitoring trends in and determinants of cardiovascular disease) project, published online on bmj.com today, found there was no added protective effect for people with thighs in excess of 60cm.
Body fat and other high risk factors such as smoking and high cholesterol were taken into account by the study.
Prof Heitmann, director of the research unit for dietary studies at Copenhagen University Hospital, said: "The adverse effects of small thighs might be related to too little muscle mass in the region."
He said this was something which could be increased by lower body physical activity.
In 1987/88, 1,463 men and 1,380 women had their thighs measured and were then followed up 10 years later to check the incidence of heart disease, and 12.5 years later to study the total number of deaths.
A total of 257 men and 155 women died, 263 men and 140 women suffered cardiovascular disease, and 103 men and 34 women suffered from heart disease.
The survivors had higher fat-free thigh circumference levels, the study found.
Dr Ian Scott, of Australia's Princess Alexandra Hospital in Brisbane, said if measuring a patient's thigh proved to be an effective way of identifying those at higher risk of heart disease and premature death, it would have "intriguing" public health implications.
But the study raised the question of whether there was a "real and independent association" between thigh size and heart disease or whether it was a "spurious or chance finding", he said.
He also questioned whether such an association was "biologically plausible".
Dr Scott said: "More research is needed to see whether measuring the thigh circumference with a tape measure adds anything more to our clinical management than eliciting risk factors from the history, examining the cardiovascular system and measuring serum lipids.
"Randomised trials are needed to test whether interventions that increase thigh muscle mass through increased physical activity - in addition to or separate from current primary prevention strategies - decrease cardiovascular risk more than current practice.
"If this approach is shown to be effective, the public health implications would be intriguing."