Big thighs might confer a health benefit according to a study showing that people with small thighs run a higher-than-average risk of developing heart disease and an early demise.
Scientists have found that men and women whose thighs are less than 60cm (23.6ins) in circumference are more likely to suffer from cardiovascular disease, and die prematurely, compared to people with thicker thighs.
They also found, however, that the apparent advantage of bigger thighs did not continue beyond the 60cm threshold. People with thighs much wider than 60cm did not fair any better than those whose thighs hovered just above the threshold.
The study, published in the British Medical Journal, is the first to link the size of the upper thigh to the risk of heart disease and premature death. The finding could lead to a medical test based on thigh size as an indicator of a person's risk of developing heart problems in later life, in much the same way that body mass index is seen as an indicator of cardiovascular risk.
Professor Berit Heitmann of Copenhagen University Hospital, who led the study, said that smaller thighs may be linked with heart disease because they indicate a lower-than-normal muscle mass in that region, which could be a factor in triggering the development of type-2 diabetes, when the hormone insulin does not work properly in controlling levels of sugar in the blood.
The study, based on monitoring 1,436 men and 1,380 women over a period of 12.5 years, found that thigh size as an indicator of heart disease risk was independent of other known risk factors, such as smoking, blood pressure and cholesterol levels. This is one of the reasons why it might be useful in doctors' surgeries, the scientists suggest.
"We found that having smaller thighs was associated with development of cardiovascular morbidity [illness] and early mortality.... General practitioners could use thigh circumference as an early marker to identify patients at later risk of cardiovascular disease and early mortality," they say.
They also suggest that exercising the legs and lower body to increase thigh size could be a useful way of decreasing the risk of heart disease. They say that it is "worrying" that half of the men and the women in the study aged between 35 and 65 have a thigh circumference that is lower than the 60cm threshold.
An editorial in the BMJ said that the study raises several questions, such as whether the link between thigh size and health risks is real or a spurious, chance finding. Although the statistical modelling used in the study was rigorous, studies on a much larger group of people will be needed to show that the association is real, it says. "Is this association biologically plausible? It would seem logical that having bigger thighs would be a reflection of greater adiposity [fatness], and that this would increase the risk of heart disease," the editorial says.
However, previous studies have also found that too little muscle or subcutaneous fat in the legs may be a risk factor in developing diabetes. "Interestingly, other studies have shown that larger hip circumference, which might be a proxy for thigh circumference, significantly reduces the risk of incident diabetes and coronary heart disease," the BMJ editorial says.