Risk Factors of Undiagnosed Diabetes Mellitus among Korean Adults: A National Cross-Sectional Study Using the KNHANES Data

Positive Additive and Multiplicative Interactions among Clustered Components of Metabolic Syndrome with Type 2 Diabetes Mellitus among Brazilian Adolescent Students

Background: It is still controversial whether the joint effect of Metabolic syndrome (MetS) components is greater than that expected based on their independent effects, regarding type 2 diabetes mellitus in adolescents. We evaluated additive and multiplicative interactions between pair-wise combinations of metabolic syndrome components regarding type 2 diabetes mellitus. Methods: We studied 37,815 Brazilian adolescents from a national school-based survey, The Study of Cardiovascular Risk Factors in Adolescents (Portuguese acronym, ERICA). A Poisson regression model was used to calculate sex-, age-, obesity-, smoking status-, sedentary behavior-, physical inactivity-, alcoholic consumption- and socioeconomic status-adjusted prevalence ratios to evaluate both additive and multiplicative interactions. Results: In the comparison of observed and expected joint effects, relative excess risk due to additive interaction (RERI) for high triglycerides and low high-density lipoprotein-cholesterol, high triglycerides and elevated waist circumference, elevated waist circumference and low high-density lipoprotein-cholesterol and elevated waist circumference and high blood pressure were 2.53 (−0.41, 5.46), 2.86 (−2.89, 8.61), 1.71 (−1.05, 4.46) and 0.97 (0.15, 1.79), respectively, thus suggesting additive interactions. Multiplicative interactions for those pairs of components were also observed, as expressed by interaction ratios > 1.0. Conclusions: The joint presence of some of the components of MetS showed a greater association with the prevalence of type 2 diabetes mellitus in adolescents than expected from the sum of their isolated effects. From a public health perspective, preventing one of the components of the pairs that interact may result in a greater reduction in the prevalence of T2DM than focusing on an individual component that does not interact with another component.

Associations of Serum Vitamin D Level with Sarcopenia, Non-Alcoholic Fatty Liver Disease (NAFLD), and Sarcopenia in NAFLD Among People Aged 50 Years and Older: The Korea National Health and Nutrition Examination Survey IV-V

Background: The role of serum 25-hydroxyvitamin D [25(OH)D] levels in the development of sarcopenia in non-alcoholic fatty liver disease (NAFLD) remains controversial. We investigated the association between vitamin D levels, occurrence of sarcopenia, NAFLD, and sarcopenia in NAFLD in adults aged >50 years. Methods: This study used data pertaining to 5396 adults aged >50 years (1870 men and 3526 women) from the 2008-2011 Korea National Health and Nutrition Examination Survey. Appendicular skeletal muscle mass adjusted by weight (ASM/Wt) was used to diagnose sarcopenia, and NAFLD was diagnosed using the NAFLD fat score. Results: The lowest quintile of serum 25(OH)D level (4.85-15.26 ng/mL) was associated with an increased occurrence of sarcopenia [odds ratio (OR) 2.65; 95% confidence interval (CI) 1.64-4.27], NAFLD (OR 1.82; 95% CI 1.19-2.96), and sarcopenia in NAFLD (OR 2.25; 95% CI 1.26-4.03) in men. In women, sarcopenia (OR 1.80; 95% CI 1.29-2.51) was also significantly associated with serum vitamin D levels, whereas high levels of vitamin D were not significantly related to NAFLD. Conclusions: Serum vitamin D levels are associated with sarcopenia, NAFLD, and sarcopenia in NAFLD. Vitamin D level can be a useful marker of sarcopenia and NAFLD, especially in men.