It’s commonly understood that obesity is a risk factor for life-threatening blood clots. Obesity causes increased pressure in the abdomen, which may reduce the ability of the calf-muscle pump to return the blood from the legs. A study, published in Circulation: Journal of the American Heart Association, provides deeper insight into the risk factor, investigating the role of weight distribution.
The key finding of the study is that women are at higher risk when they carry extra pounds on their hips, while men are at elevated risk when fat is around the waist.
The results challenge previous research that has suggested increased hip circumference is protective against blood clots.
Despite the gender difference, the overall risk related to weight distribution was seen across the middle-aged cohort involved in the study.
In a 10-year prospective study, Danish scientists assessed the relationship between body mass, weight distribution and incidence of blood clots in veins – a condition known as venous thromboembolism (VTE) – among 27,178 men and 29,876 women ages 50 to 64 years old at study entry.
READ MORE: Sugar-free energy drinks could ‘kickstart’ formation of blood clots warns doctor
VTE includes deep vein thrombosis and pulmonary embolism.
During the 10-year study, 641 VTE events occurred according to medical records.
Thromboembolism – an important cause of disease and death in adults, – results when a clot breaks free from one blood vessel and blocks another – typically from the legs to the lungs.
The Danish team found statistically significant positive associations between VTE and all measurements of body size, including body weight, body mass index (BMI), total body fat mass, waist circumference and hip circumference, among both men and women. The associations were the same regardless of the type of VTE.
Harry Potter’s Robbie Coltrane was in pain prior to death [INSIGHT]
Man, 87, diagnosed with dementia following ‘trich’ habit [ADVICE]
‘Top five’ Covid symptoms to spot as cases surge in UK [TIPS]
The researchers observed a direct relationship between VTE and weight distribution in both genders.
When adjusted for waist and hip circumference, hip circumference was positively associated with VTE in women but not men, while waist circumference was positively associated with VTE in men but not women.
This relationship was independent of other risk factors, such as smoking, physical activity, height, hypertension, diabetes, cholesterol, and, among women, the use of hormone replacement therapy.
“The BMI is a marker of excess weight and correlates well with body fat content in adults; however, it fails to consider the distribution of body fat,” said Marianne Tang Severinsen, M.D., lead author of the study and researcher in the Department of Clinical Epidemiology at Aarhus University Hospital in Aalborg, Denmark.
READ MORE: Blood clots: Coffee enjoyed by billions of people could cause ‘thicker blood’ warns doc
“The implications to the public are that all types of obesity increase the risk for VTE, but the location of body fat also plays some unknown role. For health professionals, the implication is that all types of fat distribution should be taken into account when evaluating risk for VTE.”
The findings didn’t include differences between types of fat tissue. But the results indicate that there is some distinction between the type of fat distribution in VTE as compared to coronary heart disease. Peripheral obesity measured by hip circumference has not been previously reported in association with coronary heart disease, Professor Severinsen said.
“Until now, the importance of fat distribution and VTE risk has not been evaluated,” she said.
“Our hypothesis was that fat tissue was a risk factor for VTE, independent of the distribution of the fat, and we established this.”
Other studies have also uncovered a link between weight and the risk of blood clots.
Being tall and obese may increase your risk for potentially dangerous blood clots, according to research in Arteriosclerosis, Thrombosis and Vascular Biology: Journal of the American Heart Association.
The research team analysed data from the Tromsø study, which conducts periodic health surveys of adults 25-97 years old in the Norwegian town.
Researchers collected height and obesity measures on 26,714 men and women followed a median of 12.5 years between 1994 and 2007. During that time, 461 VTEs occurred.
Obesity causes increased pressure in the abdomen, which may reduce the ability of the calf-muscle pump to return the blood from the legs.
“Obesity is also linked to a state of constant low-grade inflammation, and inflammation may render blood more susceptible to clotting,” Sigrid K. Braekkan, Ph.D., senior study author and a researcher in the Hematological Research Group at the University of Tromsø in Norway.
More research is needed to determine causal mechanisms and make specific recommendations.
What is undeniable is the toll weight gain has on the body.
“The best way to treat obesity is to eat a healthy reduced-calorie diet and exercise regularly,” says the NHS.