Association of serum lead and mercury level with cardiometabolic risk factors and liver enzymes in a nationally representative sample of adolescents: the CASPIAN-III study

Abstract

This study aims to determine the difference of serum Pb and Hg levels in adolescents with or without metabolic syndrome (MetS) and the association of serum levels of these heavy metals with cardiometabolic risk factors and liver enzymes in Iranian adolescents. The study population consisted of 320 adolescents (160 with MetS and 160 healthy controls). The relationship between serum heavy metals and cardiometabolic risk factors was assessed by linear regression. The odds ratios (OR) of having metabolic syndrome across Pb and Hg quartiles were determined by multiple logistic regression analysis. The mean (SD) of Pb and Hg concentrations were higher in adolescents with MetS than in those without it (0.83 (0.27) and 0.17 (0.01) vs. 0.65 (0.15) and 0.10 (0.08) μg/L, P = 0.01 and 0.0001, respectively). Increase in serum Pb and Hg was associated with increase in some cardiometabolic risk factors. Among boys and girls, diastolic blood pressure (DBP), fasting blood glucose, total cholesterol (TC), triglycerides (TG), and alanine aminotransaminase increased significantly across quartiles of serum Pb. Among girls, SBP, DBP, TC, and TG had a significant increase across Hg quartiles. The corresponding figure among boys was significant for SBP, DBP, and TG. Higher quartiles of Pb increased the risk of having MetS (OR 95 % CI 3.10, 2.25-4.27), the corresponding figure was 2.03, 1.75-3.16, across Hg quartiles. Our study showed significant associations between serum Pb and Hg levels with cardiometabolic risk factors in adolescents. In future surveys, the role of potential confounders should be considered more extensively. The clinical significance of these findings needs to be confirmed in longitudinal studies. By considering the origins of chronic diseases from early life, controlling environmental pollutants should be considered as a health priority for primordial or primary prevention of noncommunicable diseases.

Metabolism disrupting chemicals and metabolic disorders

“…In Bangladesh, drinking from arsenic contaminated wells was associated with increased ALT [578]. Chronic arsenic exposures were also associated with increased triglycerides in a cross-sectional study [579]; in rats, arsenic increased serum cholesterol, triglycerides, free fatty acids and phospholipids in association with increased oxidative stress and hepatic mitochondrial damage [580] as well as ALT when combined with an obesogenic agent [581, 582]. Lead and mercury exposures were associated with the fatty liver surrogate biomarker, ‘unexplained ALT elevation’ in adult NHANES [561]; and lead, but not mercury, was associated with ALT, plasma triglycerides and LDL, in Iranian adolescents [583].…”

Blood mercury concentrations are associated with decline in liver function in an elderly population: a panel study

“…A cross-sectional study in people who lived near Minamata, which was highly polluted by methylmercury, reported that the prevalence of liver disease was not significantly higher than other areas with less polluted level of methylmercury [14]. Poursafa et al [15] showed that aspartate aminotransaminase (AST) and alanine aminotransaminase (ALT) did not increase significantly with increased quartiles of blood mercury levels. In contrast, Cave et al [16] suggested a positive association between blood mercury levels and ALT in the US population.…”

Mercury Exposure in Association With Decrease of Liver Function in Adults: A Longitudinal Study

“…A previous epidemiological study showed that the Minamata area, despite being contaminated with methylmercury, did not have a higher prevalence of liver disease than other areas [ 9 ]. In a study of 320 adolescents, no significant associations were found between blood Hg levels and aspartate aminotransferase (AST) or alanine transaminase (ALT) levels [ 10 ]. Other epidemiological studies in adults and the elderly showed a significant positive association between Hg and AST, ALT, and gamma-glutamyltransferase (GGT) [ 11 - 14 ].…”

“…Previous epidemiological studies have mostly analyzed cross-sectional data [ 10 - 12 , 14 ] and did not consider fish consumption as a potential confounder, although fish are a major source of Hg exposure [ 10 , 11 , 13 , 14 ]. In addition, no studies have examined the possibility of a nonlinear relationship between blood Hg and liver function indices, or the possible role of gender.…”