Dual-energy X-ray absorptiometry-assessed adipose tissues in metabolically unhealthy normal weight Asians

Normal body mass index (BMI) is associated with lower risk for cardiometabolic diseases. However, there is a subset of individuals with BMI in this range who present with this metabolic abnormality (called metabolically unhealthy normal weight, MUHNW). Here we aimed to assess the adipose characteristics of people with MUHNW using dual-energy X-ray absorptiometry (DXA). This study included 3259 people with normal BMI who underwent health examinations from January 1, 2007 through December 31, 2016. Body fat percentage (%BF), android-gynoid percent fat ratio (AG ratio), and visceral adipose tissue (VAT) were measured simultaneously using DXA CoreScan software. Those with MUHNW comprised 12.67% of the sample. Among those with MUHNW, 71.6% of the women and 56.5% of the men showed high VAT amounts, but less than 40% of either showed high %BFs. Furthermore, considering the combined effects of fat amount and distribution, a normal BMI accompanied by high AG ratio and/or high VAT mass but low %BF presents a much higher risk for metabolic syndrome than when %BF is high, most predominantly in women. In conclusion, using DXA-measured abdominal fat, particularly VAT accumulation, is clinically more important than using %BF when assessing metabolic syndrome in those with normal BMI.