Beer belly is deadlier than being obese, warn experts

The study involved 15,184 adults aged 18 to 90

A "spare tyre" or "beer belly" of fat around the middle of thin people is deadlier than being obese, a study warned.

 

Normal-weight adults who carry fat around their midsections had twice the mortality risk than those who are overweight or obese but have normal fat distribution.

Both men and women with a normal body mass index and central obesity had greater total mortality risk than one with similar BMI but no central obesity.

Expected survival estimates were consistently lower for those with central obesity when age and BMI were controlled for.

Our findings suggest that persons with normal-weight central obesity may represent an important target population for lifestyle modification and other preventive strategies

Dr Francisco Lopez-Jimenez

Previous research found central obesity was associated with increased total and cardiovascular death.

It has been found those with a fatty tummy have less muscle mass, which is a factor associated with higher mortality risk and metabolic dysregulation.

Animal and human studies have recently shown that adipose tissue in the legs and buttocks may have a favourable effect on glucose metabolism and a persons with a central distribution of fat, particularly when measured with WHR, have less adipose tissue in the lower extremities.

But none have specifically focused on assessing the death risk in persons with normal BMI and central obesity compared with those who are overweight or obese according to BMI.

 

Cardiologist Dr Francisco Lopez-Jimenez at the Mayo Clinic, Minnesota said: "Obesity defined by BMI or measures of central obesity, such as waist-to-hip ratio (WHR) and waist circumference, is associated with increased total and cardiovascular mortality. 

"However, a recent meta-analysis showed that being overweight according to BMI was actually associated with lower total mortality, challenging the paradigm that BMI is linked to increased mortality. 

"Further whether measures of fat distribution provide any incremental risk information beyond BMI alone has been a major source of controversy."

He noted US health guidelines for tackling obesity does not recommend measuring WHR and assumes that persons with normal BMI are not exposed to any obesity-related cardiovascular risk in view of the limited available data proving otherwise.

 

US health guidelines for tackling obesity does not recomment measuring WHR

And using waist circumference information did not increase the prognostic value already provided by BMI.

The study involved 15,184 adults aged 18 to 90, just over half were women who took part in the Third National Health and Nutrition Examination Survey (NHANES III).

Body fat distribution was assessed based on anthropometric indicators alone while deaths were got from records.

Dr Francisco Lopez-Jimenez said: "Normal-weight central obesity defined by WHR is associated with higher mortality than BMI-defined obesity, particularly in the absence of central fat distribution.

 

"Our findings suggest that persons with normal-weight central obesity may represent an important target population for lifestyle modification and other preventive strategies. 

"Future studies should focus on identifying factors associated with the development of normal-weight central obesity and better understanding the effect of normal-weight central obesity on health outcomes. 

"Until such data are available, the use of BMI with measures of central obesity may provide better adiposity-related risk factor stratification cal practice than either method alone."

The study was published in Annals of Internal Medicine.