title: Association between Toenail Mercury and Metabolic Syndrome Is Modified by Selenium.
abstract: BACKGROUND
  Although Asian populations consume relatively large amounts of fish and seafood and have a high prevalence of metabolic diseases, few studies have investigated the association between chronic mercury exposure and metabolic syndrome and its effect modification by selenium.
  
  
  METHODS
  We analyzed baseline data from the Trace Element Study of Korean Adults in the Yeungnam area. Participants included 232 men and 269 women, aged 35 years or older, who had complete data regarding demographic, lifestyle, diet, toenail mercury and selenium levels, and health. Toenail mercury and selenium concentrations were measured using instrumental neutron-activation analysis. The metabolic biomarker levels were obtained through biannual medical checkups.
  
  
  RESULTS
  Higher toenail mercury levels were associated with habitual consumption of whale and shark meats, older age, obesity, smoking, alcohol drinking, and higher household income. Multivariable analysis showed a positive association between toenail mercury exposure and metabolic syndrome. In addition, this association was significantly stronger at lower selenium levels and was weaker at higher selenium levels.
  
  
  CONCLUSIONS
  The possible harmful effects of mercury on metabolic syndrome may be attenuated by high levels of selenium. Future studies are needed to suggest optimal dietary guidelines regarding fish and selenium intakes, particularly for Asians with high levels of fish intake.
authors.affiliation: Department of Food and Nutrition, Yeungnam University, Gyeongsan 38541, Gyeongbuk, Korea. kypark@ynu.ac.kr.
authors.forename: Kyong
authors.initials: K
authors.lastname: Park
authors.affiliation: Department of Food and Nutrition, Yeungnam University, Gyeongsan 38541, Gyeongbuk, Korea. daworu@ynu.ac.kr.
authors.forename: Eunmin
authors.initials: E
authors.lastname: Seo
mesh_terms: D000328:Adult; D003430:Cross-Sectional Studies; D005260:Female; D005506:Food Contamination; D005523:Food Supply; D006801:Humans; D016014:Linear Models; D016015:Logistic Models; D008297:Male; D008628:Mercury / Q000009:adverse effects / Q000032:analysis*; D024821:Metabolic Syndrome / Q000175:diagnosis / Q000453:epidemiology* / Q000517:prevention & control; D008875:Middle Aged; D015999:Multivariate Analysis; D009262:Nails / Q000737:chemistry*; D009501:Neutron Activation Analysis; D009749:Nutrition Surveys; D009752:Nutritional Status; D016017:Odds Ratio; D015995:Prevalence; D056910:Republic of Korea / Q000453:epidemiology; D018570:Risk Assessment; D012307:Risk Factors; D017747:Seafood / Q000009:adverse effects; D012643:Selenium / Q000032:analysis*; D013997:Time Factors; D014034:Toes
chemical_list: D008628:Mercury; D012643:Selenium
keywords: Asian; effect-modification; metabolic syndrome; selenium; toenail mercury