ESC 2012 Report – Normal weight individuals with belly fat at highest CVD risk

by Zara Qadir – BMI still offers a simple numeric measure of a person’s “thickness” or “thinness”.  However, normal weight individuals who carry weight concentrated in their belly have a higher death risk than obese individuals, according to research presented at ESC Congress 2012.

The study included 12,785 subjects aged 18 years and older from the Third National Health and Nutrition Examination Survey (NHANES III) and provided a representative sample of the United States population. The surveys recorded body measurements such as height, weight, waist circumference and hip circumference, as well as socioeconomic status, comorbidities, physiological and laboratory measurements. Baseline data were matched to the National Death Index to assess deaths at follow up.

Subjects were divided into three categories of BMI (normal: 18.5-24.9kg/m2; overweight: 25.0-29.9kg/m2; and obese: >30kg/m2) and two categories of waist-to-hip ratio (normal: <0.85 in women and <0.90 in men; high: =0.85 in women and =0.90 in men). Analyses were adjusted for age, sex, race, smoking, hypertension, diabetes, dyslipidemia and baseline BMI. Subjects with chronic obstructive pulmonary disease and cancer were excluded.

The mean age of subjects was 44 years old and 47.4% were men. The median follow up period was 14.3 years. There were 2,562 deaths, of which 1,138 were cardiovascular related.

Dr. Karen Sahakyan (pictured), who is a cardiology research fellow at the Mayo Clinic in Rochester, presented the results. They found that individuals with normal BMI/high waist to hip ratio (WHR) had the worst cardiovascular mortality among the 6 subgroups (unadjusted HR 3.79; adjusted HR 2.75, both P<0.0001). (see Figure 1). Total and CV mortality in this normal BMI/high WHR subgroup was even higher than in subjects with obesity by BMI (HR 1.36 and 1.20, respectively, both p<0.0001). The risk of cardiovascular death was 2.75 times higher and the risk of death from all causes was 2.08 times higher in normal weight obese people as compared with subjects with normal BMI and normal waist-to-hip ratio.
Click HERE for Figure 1

“To our knowledge it is the first study that evaluated nationwide estimates of death in central obesity even in the absence of obesity as measured by BMI,” said Dr. Sahakyan. “The high risk of death may be related to a higher visceral fat accumulation in this group, which is associated with insulin resistance and other risk factors, the limited amount of fat located on the hips and legs, which is fat with presumed protective effects and to the relatively limited amount of muscle mass.” Sahakyan and her colleagues at Mayo Cinic plan to investigate the central causes of central fat distribution.

Abstract Link: http://spo.escardio.org/abstract-book/presentation.aspx?id=106463