A cross-sectional study of the relationship between normal weight obesity and metabolic syndrome in older Korean adults

Body mass index (BMI) has the disadvantage of being unable to differentiate between the distribution and quantity of fat mass and lean mass. Normal weight obesity (NWO) is a distinct phenotype characterized by excessive body fat despite a normal BMI. The purpose of this study was to look at the relationship between NWO and metabolic syndrome in a cross-sectional design of older Korean adults aged >65 years. The current study used data from the 2008-2011 Korea National Health and Nutrition Examination Survey (1609 males and 2238 females). NWO was defined as a BMI of 18.5 to 24.9 kg/m(2) with a body fat of >26.0% in men and body fat of >36.0% in women. Metabolic syndrome was defined according to the revised National Cholesterol Education Program definition, with a modified waist circumference threshold of >90 cm for men or >85 cm for women. People with NWO had an increased risk of metabolic syndrome (odds ratio, OR = 2.357, 95% confidence interval, 95% CI = 1.747-3.179, p < 0.001 in men; OR = 1.885, 95% CI = 1.434-2.399, p < 0.001 in women) compared to people with normal weight non-obesity (OR = 1). However, after controlling the age, education, to-lean mass ratio, and intake of carbohydrates, fats, and proteins, the increased risk of NWO for metabolic syndrome was no longer significant in both genders. The current findings suggest that NWO is significantly and positively related to the risk of metabolic syndrome in older Korean adults.