The relationship of body fat distribution pattern to metabolic syndrome in the US and Taiwan

Abstract

The purposes of this study were: (1) to determine whether percent bodyfat (%BF) added to the predictive power of waist circumference (WC) to assess risks for modified metabolic syndrome (MMS, where WC was omitted as a criteria) and/or each metabolic co-morbidity by gender; and (2) to examine how the odds ratio (OR) for MMS and each co-morbidity differed by distribution patterns of %BF in overweight men and women with normal or high WC in the United States and Taiwan. Two national survey datasets, NHANES III from the U.S. and NAHSIT from Taiwan, were used. A total of 960 males and 676 females non-Hispanic White Americans (BMI between 25 and 30 kg/m²) and 291 males and 312 females Taiwanese (BMI between 24 and 27 kg/m²) met these criteria. Percent BF was divided into 4 categories based on the 50 ^th percentile split for %BF and WC as normal vs high (≥102 cm for men, 88 cm for women in the U.S. and 90cm, 80 cm in Taiwan, respectively). Odds Ratios (OR) equations were derived from logistic regression models for MMS and metabolic co-morbidities [high triglycerides (TG) ≥150 mg/dL, low HDL (<40 mg/dl for male and <50 mg/di for female), high blood pressure (BP>85/135 mm Hg) and impaired fasting glucose (IFG≥100 mg/dL)]. The lower 50^th percentile of %BF with normal WC in the sample was used as the reference.

Results. In non-Hispanic whites, WC was the strongest positive predictor for MMS and metabolic co-morbidities. WC was independent of gender, except for low HDL and high blood pressure in men. The risk for MMS increased with increasing WC, but not always with increasing BF, for people with BMI 25<30. White males with high WC and %BF had the highest risk for MMS (OR=2.1) and for high TG (OR=1.8). White females with high WC but normal %BF had the highest OR for MMS (OR=2.2) and for impaired fasting glucose (OR=3.8). The relation of WC and %BF to MMS and co-morbidities were weaker in the Taiwanese sample but similar to NHANES in that adding %BF to WC did not increase the ability to predict MMS.

Conclusion. Percent BF provided no advantage over WC in assessing obesity-related metabolic risks in the Non-Hispanic white US or in the Taiwanese samples. The relationship of fat distribution patterns to the risk for MMS differed somewhat by gender for both staples. Males with higher %BF and high WC had the greatest risk for MMS, high TG. In women, %BF was associated with decreased risk for high serum TG, low HDL, and high fasting glucose and MMS syndrome when adjusted for WC.