Normal weight obesity in Korean adults.

BACKGROUND

A better way to define obesity is in terms of the percentage of body fat (BF). Subjects with normal weight, but excess BF are vulnerable to cardiovascular diseases.

OBJECTIVE

To evaluate the prevalence and characteristics of subjects having normal weight obesity (NWO) using optimal cut-offs of the BF percentage reflecting risk factors for cardiovascular disease (CVD) in Korean adults.

DESIGN AND SETTING

The Korea National Health and Nutrition Examination Survey in the Korean population conducted in 2009-2010.

PARTICIPANTS

We surveyed 5313 men and 6904 women aged 20 years or older.

MEASUREMENTS

We investigated the relations between the BF percentage (measured by dual-energy X-ray absorptiometry) and obesity-related risk factors for CVD (diabetes mellitus, hypertension and dyslipidaemia) in Korean adults. NWO was defined as the combination of a normal body mass index (BMI; 18·5-22·9 kg/m(2) in Asian subjects) and BF percentages above the determined cut-off values.

RESULTS

There were strong and graded associations of increasing BF percentages with the prevalence of CVD risk factors. The first cut-off values (defined as being overweight) in men and women were 20·6% and 33·4% BF, respectively, and the second cut-off values (defined as obesity) were 25·7% and 36·0% BF. Thirty-two per cent of normal weight adults had BF percentages greater than or equal to the overweight or obesity cut-offs (NWO). Subjects with NWO had a lower appendicular skeletal muscle mass, a more atherogenic lipid profile and greater insulin resistance.

CONCLUSIONS

Obesity can be defined as 26% BF or greater in Korean men and 36% BF or greater in Korean women. There was a high prevalence of clustering of cardiometabolic abnormalities among subjects with NWO.