Associations between urinary heavy metal concentrations and blood pressure in residents of Asian countries.

BACKGROUND: Previous studies have suggested that exposures to heavy metals (arsenic, cadmium, lead, and selenium) may be associated with differences in blood pressure. However, the findings of these studies have been inconsistent. This study was performed to examine the associations between urinary heavy metal concentrations and blood pressure among residents of four Asian countries (Bangladesh, Indonesia, Nepal, and Vietnam). METHODS: This cross-sectional study examined 1899 adults in four Asian countries. Urinary concentrations of heavy metals were measured by inductively coupled plasma mass spectrometry. A questionnaire survey was administered regarding individual characteristics. Anthropometric measurements (height and weight) were performed. Systolic and diastolic blood pressures were measured after a short rest. Multiple linear regression models were applied to investigate associations between urinary heavy metal concentrations and blood pressure after adjustments for age, sex, and body mass index. RESULTS: The geometric means of the urinary concentrations of arsenic, cadmium, lead, and selenium were 84.6, 0.885, 2.09, and 16.5 µg/g creatinine, respectively. The urinary arsenic concentrations were slightly higher than those typically reported in non-polluted populations, while urinary cadmium, lead, and selenium concentrations were equivalent or slightly lower. The urinary lead concentrations were positively associated with both systolic and diastolic blood pressure, but urinary selenium concentrations were negatively associated with them. CONCLUSIONS: Variations in the urinary concentrations of lead and selenium were associated with blood pressure at low levels of exposure/intake.

Methylmercury exposure and neurological outcomes in Taiji residents accustomed to consuming whale meat.

Methylmercury (MeHg) is a major environmental neurotoxicant that causes damage to the central nervous system. In Japan, industrial emission of MeHg has resulted in MeHg intoxication in Minamata and Niigata, the so-called Minamata disease. Humans are exposed to MeHg derived from natural sources, primarily fish and fish predators. Therefore, MeHg continues to be an environmental risk to human health, particularly in susceptible populations that frequently consume substantial amounts of fish or fish predators such as whale. This study aimed to investigate the health effects of MeHg exposure in adults. The subjects were 194 residents (117 males, 77 females; age 20-85 years) who resided in the coastal town of Taiji, the birthplace of traditional whaling in Japan. We analyzed hair for mercury content and performed detailed neurological examinations and dietary surveys. Audiometry, magnetic resonance imaging, and electromyography were performed to diagnose neurological defects. Whole blood mercury and selenium (Se) levels were measured in 23 subjects. The geometric mean of the hair mercury levels was 14.9 µg/g. Twelve subjects revealed hair mercury levels >50 µg/g (NOAEL) set by WHO. Hair mercury levels significantly correlated with daily whale meat intake. These results suggested that residents in Taiji were highly exposed to MeHg by ingesting MeHg-contaminated whale meat. Multivariate regression analysis demonstrated no significant correlations between hair mercury levels and neurological outcomes, whereas some of the findings significantly correlated with age. A significantly positive correlation between whole blood mercury and Se levels was observed and the whole blood mercury/Se molar ratios of all subjects were <1. These findings suggested that sufficient Se intake might be one of causes of the absence of adverse effects of MeHg exposure in this study.

Cord blood levels of toxic and essential trace elements and their determinants in the Terai region of Nepal: a birth cohort study.

The purpose of this study is to evaluate the cord blood level of toxic and trace elements and to identify their determinants in Terai, Nepal. One hundred pregnant women were recruited from one hospital in Chitwan, Nepal in 2008. The cord blood levels of toxic [lead (Pb), arsenic (As), and cadmium (Cd)], essential trace elements [zinc (Zn), selenium (Se), and copper (Cu)], demographic, socioeconomic, and behavioral variables were measured. The mean values of Pb, As, Cd, Zn, Se, and Cu in cord blood level were found as 31.7, 1.46, 0.39, 2,286, 175, and 667 µg/L, respectively. In the multivariate regression model, cord blood As levels from less educated mothers were higher than those from educated mothers (coefficient = -0.01, 95% confidence interval [CI] = -0.02-0.00). The maternal age was positively associated with the cord blood Cd level (coefficient = 0.02, 95% CI = 0.01-0.03), while it was negatively associated with the cord blood As level (coefficient = -0.01, 95% CI = -0.03--0.01). Cord blood levels of Pb, Zn, Se, and Cu were not associated with maternal age, socioeconomic status, living environment, and smoking status. As and Cd levels were relatively lower than those reported in previous studies in Asia, while the levels of Pb and the trace elements were similar. Less educated mothers are more likely to become a higher in utero As source to their fetus, and fetuses of older mothers were more likely to have higher in utero Cd exposure in Terai, Nepal.