Men and women whose thighs are less than 60cm in circumference have a higher risk of premature death and heart disease, according to research published on bmj.com today. The study also concluded that individuals whose thighs are wider than 60cm have no added protective effect.

Lead author, Professor Berit Heitmann, based at Copenhagen University Hospital, says his research may help GPs identify patients who are at an increased risk of early death and developing heart disease.

While several studies have already demonstrated that being either very overweight or underweight are related to premature death and disease, this is the first to investigate the implications of thigh size on health.

Almost 3000 individuals took part in the study in Denmark - this included 1463 men and 1380 women. Participants were examined in 1987/88 for height, weight, thigh, hip and waist circumference and body composition. They were then followed up for 10 years for incidence of heart disease and 12.5 years for total number of deaths.

During the follow-up period 257 men and 155 women died, also 263 men and 140 women experienced cardiovascular disease and 103 men and 34 women suffered from heart disease. When assessing the results, the authors found that the survivors had higher fat-free thigh circumference levels.

The relationship between thigh size and early death and disease was found after taking body fat and other high risk factors (such as smoking and high cholesterol) into account. The authors therefore suggest that the risk from narrow thighs could be associated with too little muscle mass in the region. This is problematic because it may lead to low insulin sensitivity and type 2 diabetes and, in the long run, heart disease, they explain.

The authors conclude that the study "found that the risk of having small thighs was associated with development of cardiovascular morbidity and early mortality. This increased risk was found independent of abdominal and general obesity, lifestyle and cardiovascular risk factors such as blood pressure and lipids related to early cardio vascular morbidity and mortality".

The authors believe that doctors could use thigh size as an early marker for at risk patients and suggest that individuals increase lower body exercise in order to increase the size of the their thighs if necessary. Further research would be needed, however, to assess whether this approach was worthwhile.