That spare tyre you're carrying around could be increasing your risk of an early death, a new study suggests.
What's more, the increased risk associated with having a larger waistline occurs even if a person's body-mass index (BMI) indicates a healthy weight, said lead researcher Emmanuel Stamatakis. He's an associate professor with the University of Sydney in Australia.
People who carry extra weight around the middle – also called "central obesity" – but have a normal BMI have a 22% higher risk of death than people whose fat is stored elsewhere in their bodies, the study found. In folks with a BMI that indicates obesity, the risk of early death was 13% higher for those with central obesity.
Link to gut size
The study, which was published online in the Annals of Internal Medicine, also found that a large gut poses an even greater hazard for heart health. The risk of heart-related death is 25% higher for someone with central obesity and a normal BMI. It's 26% greater for those with an overweight BMI and extra abdominal girth, and 56% higher for an obese BMI and central obesity, the study found.
BMI is a rough estimate of a person's body fat based on height and weight measurements. Normal BMI is 18.5 to 24.9, according to the US Centers for Disease Control and Prevention. Overweight is 25 to 29.9, and obese is 30 and over.
Waist-to-hip ratio is a measurement used to determine if there is excess belly fat. Stamatakis said waist-to-hip ratio is calculated by dividing your waist measurement by your hip measurement.
"If a person's waist-to-hip ratio is over 0.85 if they are female, or over 0.90 if they are male, then they should be concerned and look into ways to alter their lifestyle to lose or reduce the 'paunch'," Stamatakis said.
South Africa has the highest overweight and obesity rate in sub-Saharan Africa, with up to 70% of women and a third of men being classified as overweight or obese.
10 years of follow-up
Ruth Loos is director of the genetics of obesity and related metabolic traits programme at the Charles Bronfman Institute of Personalized Medicine at Mount Sinai in New York City.
"Studies have been fairly consistent in showing that waist-to-hip ratio contributes to disease," Loos said.
For this latest study, researchers looked at almost 43 000 participants in the Health Survey for England and the Scottish Health Survey. Each person's BMI and waist-to-hip ratio was compared against their health history during 10 years of follow-up.
The study participants' average age was 58. And, just over half had central obesity. 44% were overweight. One quarter were obese. Folks who were overweight and obese were much more likely to have central obesity than people with a normal BMI.
Men are more likely to store fat around their middle, which could mean they are more likely to develop this risk, Loos said. Women tend to store fat in their hips and buttocks.
Excessive fat around the waist has been linked to insulin resistance, high cholesterol and increased inflammation, Stamatakis said. These all are risk factors for heart disease.
A high waist-to-hip ratio also can indicate less muscle mass in the legs, which also increases heart disease risk, Stamatakis added.
"If you store fat around your belly and around your organs, it's going to affect your liver function, it's going to affect your heart function," Loos said.
"There's no way of specifically targeting that belly fat," Loos said. "Even exercises like doing sit ups are not going to specifically help you lose fat in your belly."
Both Stamatakis and Loos said people with belly fat should take the following steps to improve their health:
- Eating right
- Stopping smoking
- Reducing or cutting out drinking
Unfortunately, weight loss efforts will not necessarily eliminate your spare tyre. Weight loss tends to occur evenly across the entire body, and cannot be directed toward any exact store of fat, Loos noted.
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