A study in the journal Endocrine Connections has explored the relationship between thigh circumference and high blood pressure, also known as hypertension, in a Chinese population with an average age of 50.
The researchers found that in people with overweight or obesity, larger thigh circumference was associated with a lower prevalence of high blood pressure.
According to the World Health Organization (WHO), hypertension affects approximately 1 in 4 men and 1 in 5 women.
It can increase the risk of a range of diseases, and the WHO report that high blood pressure is “a major cause of premature death worldwide.”
As the authors of the study in Endocrine Connections note, people with hypertension in its early stages experience few, if any, symptoms.
If a person does not receive treatment for high blood pressure, they face a greater risk of significant illness or death. In the study authors’ words, “Hypertension is a silent killer.”
They note that previous research found positive links between upper-body obesity and hypertension, while lower-body obesity is positively associated with metabolic profiles that might protect against hypertension.
Because calculating body fat percentage can be costly and timely, researchers often use the circumference of certain body parts to estimate the quantity of fat in the body, the authors explain.
They also cite previous findings that a high waist to thigh circumference ratio indicates a greater risk of hypertension.
In their present study, the authors investigated whether there is an association between thigh circumference alone and hypertension.
The study drew on data from a larger study, which looked at the risk factors for cancer among Chinese people with diabetes.
The study population consisted of 9,520 people, all over the age of 40, including 3,095 men and 6,425 women.
The participants filled in a questionnaire, providing the authors with information related to hypertension.
Physicians measured the participants’ thigh circumferences and also reported the average circumference of each participant’s thighs.
The participants also underwent blood pressure testing after they had rested for 5 minutes.
After analyzing the data, the authors found that a larger thigh circumference was associated with a lower rate of hypertension among people with overweight or obesity.
According to study author Zhen Yang, Ph.D., from Shanghai Jiao Tong University, in China, this suggests that “In contrast to stomach fat, leg fat may be beneficial for metabolism.”
“The most likely cause of this association is that there is more thigh muscle and/or fat deposited under the skin which secretes various beneficial substances that help keep blood pressure in a relatively stable range.”
– Zhen Yang, Ph.D.
Interestingly, the authors point out that they “did not observe a significant association between thigh circumference and hypertension in normal-weight individuals.”
This could lend credence to Yang’s suggestion that thigh muscle may also be beneficially contributing to a person’s metabolism.
The authors acknowledge some limits to their study. First, because they had been focusing on thigh circumference, they are unable to give detail about how the type and quantity of thigh fat may relate to hypertension.
Furthermore, the link between thigh circumference and hypertension is only observational, not causal: They are unsure of the mechanism behind the association.
Finally, the authors point out that their sample size consisted of middle-aged Chinese people. They acknowledge that a population that includes younger people or people of other ethnicities might lead to different findings.
To take the research forward, Yang and the team intend to look in detail at the composition of the thigh to better understand any link with hypertension.