Blood Mercury and Insulin Resistance in Nondiabetic Koreans (KNHANES 2008-2010)

PURPOSE: Blood mercury levels are associated with inflammation, and chronic low-grade inflammation is a cause of insulin resistance. This study aimed to investigate the association between serum mercury and insulin resistance. MATERIALS AND METHODS: Subjects from the 2008-2010 Korean National Health and Nutrition Examination Survey were selected (n=29235) and the relevant data of 5388 subjects (2643 males and 2745 females) were analyzed cross-sectionally. Homeostasis Model Assessment for Insulin Resistance (HOMA-IR) was compared according to blood mercury quartiles, and the odds ratio (OR) of having the highest quartile of HOMA-IR according to blood mercury quartiles was calculated. RESULTS: Blood mercury levels in men and women were 29.4 nmol/L and 20.5 nmol/L, respectively, and fasting blood sugar (FBS), insulin, and HOMA-IR were significantly correlated with blood mercury levels. The correlation was stronger in men than in women. In men, FBS and HOMA-IR showed step-wise increases as the quartiles of blood mercury increased; only HOMA-IR differed significantly in the third and fourth blood mercury quartiles, compared to the first quartile. In women, however, both FBS and HOMA-IR differed significantly in the third and fourth blood mercury quartiles, compared to the first quartile. Among men, the OR of being in the highest HOMA-IR quartile was greatest for the highest blood mercury quartile (OR=1.720, 95% CI; 1.172-2.526), compared with the lowest quartile. CONCLUSION: In this large population-based study, blood mercury levels were weakly correlated with HOMA-IR and may be a risk factor for insulin resistance in nondiabetic Koreans.

Dietary Calcium and Framingham Risk Score in Vitamin D Deficient Male (KNHANES 2009-2011)

PURPOSE: The association between excess calcium intake and cardiovascular mortality has already been reported. In the present study, we investigated the relation between dietary calcium intake and Framingham Risk Score (FRS) according to serum 25-hydroxyvitamin D [25(OH)D] status. MATERIALS AND METHODS: A total of 7809 subjects (3452 males and 4357 female) aged over 40 years were selected for this cross-sectional study from data obtained from the Korea National Health and Nutrition Examination Survey (2008-2011). Daily dietary calcium intake was categorized into 1200 mg/day and serum 25(OH)D concentration classified into 75 mmol/L. The FRS was compared by the daily dietary calcium intake categories according to 25(OH)D concentration after adjustment with relevant variables in both genders. RESULTS: Higher FRS was observed in males with both 1200 mg of dietary calcium intake and females with 1200 mg of dietary calcium intake groups in both genders after adjustments for relevant variables. FRS was significantly higher in the group with >1200 mg of dietary calcium intake and serum 25(OH)D 1200 mg/day) dietary calcium intake were related with higher FRS in both genders. In particular, higher FRS was observed in the excess (>1200 mg/day) dietary calcium intake male group under vitamin D deficiency (<50 nmol/L).