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OBJECTIVES: The question of whether the consumption of antioxidants prevents and alleviates metabolic syndrome (MetS) by reducing insulin resistance remains controversial. The aim of this study was to assess whether the intake of vitamin A (including ß-carotene), vitamin C, fruits, or vegetables was negatively associated with MetS in Korean adults aged ≥ 20 y. METHODS: We conducted a cross-sectional study of 27,656 adults ≥ 20 y of age who participated in the 2007-2012 Korean National Health and Nutrition Examination Survey. Daily intake of vitamin A and vitamin C was assessed by 24-h recall, and the consumption of fruits and vegetables was determined using a food frequency questionnaire. Odds ratios (ORs) for MetS were calculated for log2-transformed vitamin A and C intake values and for the interaction of sex with vitamin A and C intake, after covariate adjustment. RESULTS: Interactions were seen between total vitamin A and C intake and sex for MetS. With a twofold increase in total vitamin A and C intake in women, the ORs (95% confidence intervals) for metabolic syndrome were 0.942 (0.901-0.985) and 0.933 (0.883-0.987), indicating decreases of 5.8% and 6.7% in MetS, respectively. There were no equivalent decreases in men. Women in the second and highest tertiles of fruit intake exhibited 17.5% and 21.8% lower incidences of MetS, respectively, compared with women in the lowest tertile. CONCLUSIONS: The intake of total vitamin A and C, as well as moderate and high fruit intake, may have alleviated MetS in women, but not in men, in a representative sample of the general South Korean population.
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Ácido Ascórbico/administración & dosificación , Pueblo Asiatico , Frutas , Síndrome Metabólico/epidemiología , Vitamina A/administración & dosificación , Adulto , Antioxidantes/administración & dosificación , Glucemia/metabolismo , Presión Sanguínea , Índice de Masa Corporal , HDL-Colesterol/sangre , Estudios Transversales , Ayuno , Femenino , Humanos , Resistencia a la Insulina , Masculino , Recuerdo Mental , Persona de Mediana Edad , Encuestas Nutricionales , Prevalencia , República de Corea/epidemiología , Factores de Riesgo , Encuestas y Cuestionarios , Triglicéridos/sangre , Verduras , Circunferencia de la Cintura , Adulto JovenRESUMEN
BACKGROUND: It is well known that lead exposure induces neurotoxic effects, which can result in a variety of neurocognitive dysfunction. Especially, occupational lead exposures in adults are associated with decreases in cognitive performance including working memory. Despite recent advances in human neuroimaging techniques, the neural correlates of lead-exposed cognitive impairment remain unclear. Therefore, this study was aimed to compare the neural activations in relation to working memory function between the lead-exposed subjects and healthy controls. METHODOLOGY/PRINCIPAL FINDINGS: Thirty-one lead-exposed subjects and 34 healthy subjects performed an n-back memory task during MRI scan. We performed fMRI using the 1-back and 2-back memory tasks differing in cognitive demand. Functional MRI data were analyzed using within- and between-group analysis. We found that the lead-exposed subjects showed poorer working memory performance during high memory loading task than the healthy subjects. In addition, between-group analyses revealed that the lead-exposed subjects showed reduced activation in the dorsolateral prefrontal cortex, ventrolateral prefrontal cortex, pre supplementary motor areas, and inferior parietal cortex. CONCLUSIONS/SIGNIFICANCE: Our findings suggest that functional abnormalities in the frontoparietal working memory network might contribute to impairments in maintenance and manipulation of working memory in the lead-exposed subjects.
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Intoxicación por Plomo/psicología , Memoria a Corto Plazo/efectos de los fármacos , Enfermedades Profesionales/psicología , Anciano , Estudios de Casos y Controles , Corteza Cerebral/fisiopatología , Femenino , Neuroimagen Funcional , Humanos , Plomo/sangre , Intoxicación por Plomo/fisiopatología , Imagen por Resonancia Magnética , Persona de Mediana Edad , Enfermedades Profesionales/fisiopatologíaRESUMEN
Discrepancies have been reported in the relationships between iron and cadmium concentrations. The distribution of blood cadmium concentrations was assessed in a representative sample of Korean adolescents participating in the Korean National Health and Nutritional Examination Survey (KNHANES) 2010-2011, and the association between blood cadmium and iron concentrations was determined. This study was based on data from KNHANES, in which a rolling sampling design was used to perform a complex, stratified, multistage probability cluster survey of a representative sample of the noninstitutionalized civilian population in South Korea. Serum ferritin was categorized as low (<15.0 µg/L), low normal (15.0-<30.0 µg/L for girls, 15.0-<50.0 µg/L for boys), or normal (≥30.0 µg/L for girls, ≥50.0 µg/L for boys), and the association between serum ferritin and blood cadmium concentrations was assessed after adjustment for various demographic and lifestyle factors. The geometric mean (GM) of blood cadmium was significantly higher among both boys and girls in the low than in the normal ferritin group. After controlling for covariates, multiple regression analysis showed that blood cadmium concentration was inversely correlated with serum ferritin concentration in both boys and girls. In conclusion, iron deficiency is associated with increased blood cadmium concentrations in a representative sample of Korean adolescents, as evaluated in KNHANES.
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Cadmio/sangre , Deficiencias de Hierro , Hierro/sangre , Adolescente , Adulto , Niño , Estudios Transversales , Femenino , Ferritinas/sangre , Humanos , Masculino , Análisis Multivariante , Análisis de Regresión , Adulto JovenRESUMEN
INTRODUCTION: We herein used data from the Korean National Health and Nutritional Examination Survey (KNHANES) 2008-2012 to examine the associations between blood mercury levels and subclinical changes of liver function in a representative sample of the adult Korean population. METHODS: This study was based on data obtained from KNHANES, in which a rolling sampling design was used to perform a complex, stratified, multistage probability cluster survey of a representative sample of the non-institutionalized civilian population in South Korea. The associations between subclinical hepatic changes and blood mercury levels were assessed after adjustment for various demographic and lifestyle factors. RESULTS: Multivariate linear regression analyses revealed that each doubling of blood mercury increased serum aspartate transaminase (AST) by 0.676U/L and serum alanine transaminase (ALT) by 1.067U/L. The mean differences (95% CI) in serum AST and ALT between the lowest and highest quartiles were statistically significant at 1.249 (0.263-2.235)U/L and 2.248 (0.648-3.848), respectively. Logistic regression analysis showed that the odd ratios for having serum AST and ALT levels above the median were statistically significant in both the models according to the increase of blood mercury. The risks of having serum AST and ALT levels higher than the median among subjects in 4th quartile of blood mercury were 1.524 and 1.947, respectively. DISCUSSION: The present findings show that subclinical changes of liver function are associated with blood mercury levels. This is the first study to show an association between blood mercury levels and mild liver dysfunction, as a possible proxy measure of nonalcoholic fatty liver disease (NAFLD), in Asian population.
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Alanina Transaminasa/sangre , Aspartato Aminotransferasas/sangre , Hígado/metabolismo , Mercurio/sangre , Adulto , Estudios Transversales , Humanos , Modelos Lineales , Hígado/enzimología , Persona de Mediana Edad , Análisis Multivariante , Encuestas Nutricionales , República de Corea/epidemiología , Adulto JovenRESUMEN
INTRODUCTION: We present data from the Korean National Health and Nutritional Examination Survey (KNHANES) 2010-11 on the distribution of blood lead levels, and examine their association with iron deficiency in a representative sample of the adolescent Korean population. METHODS: This study was based on data obtained from KNHANES, in which a rolling sampling design was used to perform a complex, stratified, multistage probability cluster survey of a representative sample of the non-institutionalized civilian population in South Korea. Serum ferritin was categorized into three levels: low (serum ferritin <15.0µg/L), low normal (serum ferritin 15.0-30.0µg/L for girls and 15.0-50.0 for boys), and normal (serum ferritin ≥30.0µg/L for girls and ≥50.0 for boys), and its association with blood lead levels was assessed after adjustment for various demographic and lifestyle factors. RESULTS: The geometric mean (GM) of blood lead in the low serum ferritin group was significantly higher than that in the normal group among boys but not girls. After controlling for covariates, multiple regression analysis showed that blood lead was inversely correlated with serum ferritin levels in boys and pre-menarche girls only. DISCUSSION: The present study shows that iron deficiency increases blood lead levels in a representative sample of the male and pre-menarche female adolescent population, as evaluated in KNHANES. The confounding effect of estrogen on blood lead levels should be considered.
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Ferritinas/sangre , Deficiencias de Hierro , Plomo/sangre , Adolescente , Niño , Estudios Transversales , Femenino , Humanos , Masculino , Análisis de Regresión , República de Corea/epidemiología , Población Rural , Espectrofotometría Atómica , Población Urbana , Adulto JovenRESUMEN
We examined familial bone mineral density (BMD) interactions between parents and children and lifestyle factors affecting BMD in the Korean general population of children under 20 and parents under 50 years of age. This cross-sectional study included 2,453 participants (667 daughters, 705 sons, 719 mothers, and 362 fathers) in the 2009-2010 Korean National Health and Nutrition Examination Survey. We calculated prevalence ratios and 95 % confidence intervals for BMD values of whole femur, femur neck, lumbar spine, and whole body excluding the head being in the low tertile in adolescents according to parental BMD tertile after adjusting for physical, lifestyle, and dietary factors. For daughters and sons, there were significant differences in BMD at the four bone sites according to age group, body fat percentage, regular walking and exercise, and milk consumption compared to the reference value for each classification category. Surprisingly, there were no differences in BMD according to serum 25-OH-D levels. Birth order affected BMD of only whole body except head, but its impact was less than that of lifestyle factors. The mean differences in BMD between daughters and sons in the first and third parental BMD tertiles were statistically significant. Notably, the prevalence ratio of whole body without head BMD being in the low tertile increased eight and ten-folds in adolescent daughters and sons, respectively, when parents were in the low BMD tertile. In specific bone regions, parental BMD had a greater effect on total femur in daughters but in the lumbar spine in sons. In conclusion, parental BMD positively influences BMD in daughters and sons after adjustment for environmental parameters. This suggests that the children from parents with low BMD need to make an extra effort to increase BMD through dietary and lifestyle changes.
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Densidad Ósea/fisiología , Adolescente , Adulto , Estudios Transversales , Femenino , Humanos , Estilo de Vida , MasculinoRESUMEN
BACKGROUND & AIMS: Sarcopenia, loss of muscle mass and function, is one of the major risk factors for metabolic diseases and vitamin D is also positively associated with their prevalence. We examined whether vitamin D deficiency was positively associated with sarcopenia in a gender-specific manner in adults aged ≥50 years, independent of other covariates and possible confounders, including body composition, blood tests, including serum parathyroid hormone (PTH) levels, dietary intake, and hormone replacement therapy in women. METHODS: This cross-sectional study included 2258 men and 3005 women aged ≥50 years who participated in the 2009-2010 Korean National Health and Nutrition Examination Survey. Sarcopenia was defined as appendicular skeletal muscle mass/body weight <2 standard deviations below gender-specific means for young adults. Vitamin D status was represented by serum 25-hydroxyvitamin D (25-OH-D) levels. Adjusted odds ratios for having sarcopenia were calculated according to vitamin D status, while controlling for covariates that affect vitamin D status and body composition using logistic regression analysis with incorporating the sample weights for the complex sample design of the survey. RESULTS: Sarcopenia showed a strong inverse association with serum 25-OH-D levels in women, but not men, independent of other covariates and possible confounders. Sarcopenia was negatively associated with dietary intakes of energy, protein, and carbohydrates in both men and women, but walking and exercise showed no significant relationship with sarcopenic status. Sarcopenic status was significantly associated with serum total 25-OH-D and cholesterol levels only in women and with serum PTH levels only in men. The risk of sarcopenia was increased, by 1.46-fold, by lowering serum 25-OH-D by 10 ng/mL only in women. CONCLUSIONS: Serum 25-OH-D levels were a negative modulator of sarcopenia only in women aged ≥50 years in a Korean population.