Lower Leg Fat Depots Are Associated with Albuminuria Independently of Obesity, Insulin Resistance, and Metabolic Syndrome (Korea National Health and Nutrition Examination Surveys 2008 to 2011)

BACKGROUND: Although the involvement of obesity in metabolic disorders is well known, leg fat depot influences on albuminuria have not been determined. METHODS: This population-based, cross-sectional study used a nationally representative sample of 2,076 subjects aged ≥20 years from the Korea National Health and Nutrition Examination Surveys of 2008 to 2011. The ratio of leg fat to total fat (LF/TF ratio) was assessed by dual X-ray absorptiometry, and albuminuria was defined as more than one positive dipstick test or an albumin-to-creatinine ratio of ≥30 mg/g. RESULTS: Individuals whose LF/TF ratio was in the lowest tertile showed a higher proportion of albuminuria than those in the highest tertile (odds ratio [OR], 2.82; 95% confidence interval [CI], 2.01 to 3.96; P<0.001). This association was observed in both sexes, all age groups, and all subgroups stratified by body mass index, waist circumference, homeostasis model assessments of insulin resistance, and the presence of metabolic syndrome (all, P<0.05). Multiple logistic regression analyses also demonstrated that the lowest LF/TF ratio was independently associated with albuminuria risk (OR, 1.55 to 2.16; all, P<0.05). In addition, the risk of albuminuria was higher in sarcopenic individuals with lower LF/TF ratios than in the highest LF/TF ratio subjects without sarcopenia (OR, 3.73; 95% CI, 2.26 to 6.13). CONCLUSION: A lower LF/TF ratio was associated with an increased risk of albuminuria independent of obesity, insulin resistance, and metabolic syndrome, and when combined with sarcopenia, the albuminuria risk synergistically increased. Hence, our findings may have implications to improve risk stratification and recommendations on body fat distribution in the general population.