RESUMO
BACKGROUND: Visual functions are known to be sensitive to toxins such as mercury (Hg) and lead (Pb), while omega-3 fatty acids (FA) and selenium (Se) may be protective. In the Tapajós region of the Brazilian Amazon, all of these elements are present in the local diet. OBJECTIVE: Examine how near visual contrast sensitivity and acquired color vision loss vary with biomarkers of toxic exposures (Hg and Pb) and the nutrients Se and omega-3 FA in riverside communities of the Tapajós. METHODS: Complete visuo-ocular examinations were performed. Near visual contrast sensitivity and color vision were assessed in 228 participants (≥15 years) without diagnosed age-related cataracts or ocular pathologies and with near visual acuity refracted to at least 20/40. Biomarkers of Hg (hair), Pb (blood), Se (plasma), and the omega-3 FAs eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) in plasma phospholipids were measured. Multiple linear regressions were used to examine the relations between visual outcomes and biomarkers, taking into account age, sex, drinking and smoking. RESULTS: Reduced contrast sensitivity at all spatial frequencies was associated with hair Hg, while %EPA, and to a lesser extent %EPA+DHA, were associated with better visual function. The intermediate spatial frequency of contrast sensitivity (12 cycles/degree) was negatively related to blood Pb and positively associated with plasma Se. Acquired color vision loss increased with hair Hg and decreased with plasma Se and %EPA. CONCLUSIONS: These findings suggest that the local diet of riverside communities of the Amazon contain toxic substances that can have deleterious effects on vision as well as nutrients that are beneficial for visual function. Since remediation at the source is a long process, a better knowledge of the nutrient content and health effects of traditional foods would be useful to minimize harmful effects of Hg and Pb exposure.
Assuntos
Visão de Cores , Sensibilidades de Contraste , Dieta , Contaminação de Alimentos , Alimentos Marinhos , Adolescente , Adulto , Idoso , Biomarcadores/sangue , Brasil , Defeitos da Visão Cromática/etiologia , Defeitos da Visão Cromática/prevenção & controle , Estudos Transversais , Dieta/efeitos adversos , Ácidos Graxos Ômega-3/sangue , Feminino , Cabelo/química , Humanos , Chumbo/efeitos adversos , Chumbo/sangue , Modelos Lineares , Masculino , Compostos de Mercúrio/efeitos adversos , Compostos de Mercúrio/análise , Pessoa de Meia-Idade , Análise Multivariada , Fatores de Risco , Alimentos Marinhos/efeitos adversos , Alimentos Marinhos/análise , Selênio/sangue , Testes Visuais , Adulto JovemRESUMO
Selenium (Se) is an essential element and a well-known anti-oxidant. In the Lower Tapajós River region of the Brazilian Amazon, biomarkers of Se range from normal to very high. The local traditional diet includes important Se sources such as Brazil nuts, chicken, game meat and certain fish species. Some studies have reported alterations in keratin structure, gastrointestinal problems and paresthesia in populations with high Se intake. The objective of the present study was to evaluate cutaneous and garlic odor of the breath signs and sentinel symptoms of Se toxicity (selenosis) in relation to Se status in communities along the Tapajós River. Participants (N=448), aged 15-87 years, were recruited from 12 communities. Se concentrations were measured in blood (B-Se) and plasma (P-Se) by ICP-MS. A nurse performed an examination of the hair, nails, skin and breath for signs of Se toxicity. Interview-administered questionnaires were used to collect information on socio-demographics, medical history and possible symptoms of Se toxicity. In this population, the median levels of B-Se and P-Se were 228.4 µg/L (range 103.3-1500.2 µg/L) and 134.8 µg/L (range 53.6-913.2 µg/L) respectively. Although B-Se and P-Se surpassed concentrations considered toxic (B-Se: 1000 µg/L (U.S. EPA, 2002)), no dermal or breath signs or symptoms of Se toxicity were associated with the biomarkers of Se status. In the present study population, where Se intake is mostly from traditional diet, there is no evidence of selenosis. These findings support the need to re-assess Se toxicity considering factors such as the chemical form of Se exposure, route of exposure (inhaled versus ingested), co-exposures to toxic elements such as mercury. Considering the current food transition towards a western diet in the Amazon, further studies should address the possible association between high Se status and cardiometabolic health in this study population.
Assuntos
Dieta/estatística & dados numéricos , Micronutrientes/intoxicação , Selênio/intoxicação , Adulto , Bertholletia , Biomarcadores/análise , Biomarcadores/metabolismo , Brasil , Testes Respiratórios , Estudos Transversais , Feminino , Cabelo/química , Humanos , Masculino , Micronutrientes/metabolismo , Pessoa de Meia-Idade , Unhas/química , Selênio/análise , Selênio/metabolismo , Pele/metabolismoRESUMO
Since 1995, the Caruso Project used an Ecosystem Approach to Human Health to examine mercury (Hg) exposure in fish-eating communities in the Brazilian Amazon and develop interventions to maximise nutrition from traditional diet and minimise toxic risk. In 1995, 2000 and 2006, this study followed fish consumption, Hg levels, and visual and motor functions in 31 villagers. Questionnaires gathered information on socio-demographics and diet. Hair Hg (H-Hg) levels were measured. Visual acuity, colour vision, manual dexterity and grip strength were assessed. Data was analysed using general linear models of repeated measures. Total fish consumption, similar in 1995 and 2000, decreased in 2006. Carnivorous fish consumption initially decreased and then remained stable, whereas non-carnivorous fish consumption first increased and then decreased. H-Hg declined from 17.6 to 7.8 µg/g. Visual functions showed a significant decrease over time, with those with H-Hg ≥ 20 µg/g in 1995 showing greater loss. Motor functions showed initial improvement and then returned to the 1995 performance level. Decrease in Hg exposure is attributed to the intervention and socio-economic changes in the village. While there may be a certain reversibility of motor deficits, visual capacities may decrease progressively with respect to exposure prior to the intervention.
Assuntos
Contaminação de Alimentos/análise , Intoxicação do Sistema Nervoso por Mercúrio/complicações , Mercúrio/análise , Poluição Química da Água/análise , Adolescente , Adulto , Animais , Brasil/epidemiologia , Visão de Cores/efeitos dos fármacos , Estudos Transversais , Comportamento Alimentar , Feminino , Peixes/metabolismo , Cabelo/química , Força da Mão , Humanos , Masculino , Intoxicação do Sistema Nervoso por Mercúrio/epidemiologia , Intoxicação do Sistema Nervoso por Mercúrio/etiologia , Pessoa de Meia-Idade , Rios/química , Alimentos Marinhos/análise , Poluição Química da Água/efeitos adversos , Adulto JovemRESUMO
OBJECTIVE: To examine the associations between near and distant visual acuity and biomarkers of Hg, Pb, n-3 fatty acids and Se from the local diet of fish-eating communities of the Tapajós River in the Brazilian Amazon. DESIGN: Visuo-ocular health and biomarkers of Hg (hair, whole blood, plasma), Pb (whole blood), Se (whole blood and plasma) and n-3 fatty acids (plasma total phospholipids) were assessed in a cross-sectional study. SETTING: Lower Tapajós River Basin (State of Pará, Brazil), May to July 2006. SUBJECTS: Two hundred and forty-three adults (≥15 years) without diagnosed age-related cataracts or ocular pathologies. RESULTS: Near visual acuity was negatively associated with hair Hg and positively associated with %DHA, with a highly significant Log Hg × age interaction term. Stratifying for age showed that while young people presented good acuity, for those aged ≥40 years, clinical presbyopia was associated with hair Hg ≥ 15 µg/g (OR = 3·93, 95% CI 1·25, 14·18) and %DHA (OR = 0·37, 95% CI 0·11, 1·11). A similar age-related pattern was observed for distant visual acuity in relation to blood Pb, but the evidence was weaker. CONCLUSIONS: These findings suggest that Hg and Pb may affect visual acuity in older persons, while DHA appears to be protective for near visual acuity loss. In this population, with little access to eye care, diet may have an important influence on visuo-ocular ageing.
Assuntos
Dieta , Contaminação de Alimentos/análise , Acuidade Visual , Poluentes Químicos da Água/análise , Adolescente , Adulto , Idoso , Animais , Biomarcadores/sangue , Brasil , Estudos Transversais , Monitoramento Ambiental/métodos , Ácidos Graxos Ômega-3/sangue , Feminino , Peixes , Cabelo/química , Humanos , Chumbo/sangue , Modelos Logísticos , Masculino , Mercúrio/sangue , Pessoa de Meia-Idade , Análise Multivariada , Medição de Risco , Rios , Selênio/sangue , Fatores Socioeconômicos , Adulto JovemRESUMO
BACKGROUND: Mercury (Hg) is a ubiquitous environmental contaminant with neurodevelopmental and immune system effects. An informative biomarker of Hg-induced immunotoxicity could aid studies on the potential contribution to immune-related health effects. OBJECTIVES: Our objectives were to test the hypothesis that methylmercury (MeHg) exposures affect levels of serum biomarkers and to examine interactions between Hg and selenium (Se) in terms of these responses. METHODS: This cross-sectional epidemiological study assessed adults living along the Tapajós River, a system long affected by MeHg. We measured antinuclear (ANA) and antinucleolar (ANoA) autoantibody levels and eight cytokines in serum samples (n = 232). Total Hg (including MeHg) and Se were measured in blood, plasma, hair, and urine. RESULTS: The median (range) total Hg concentrations were 14.1 µg/g (1.1-62.4), 53.5 µg/L (4.3-288.9), 8.8 µg/L (0.2-40), and 3.0 µg/L (0.2-16.1) for hair, blood, plasma, and urine, respectively. Elevated titers of ANA (but not ANoA) were positively associated with MeHg exposure (log-transformed, for blood and plasma), unadjusted [odds ratio (OR) = 2.6; 95% confidence interval (CI): 1.1, 6.2] and adjusted for sex and age (OR = 2.9; 95% CI: 1.1, 7.5). Proinflammatory [interleukin (IL)-6 and interferon (IFN)-γ], anti-inflammatory (IL-4), and IL-17 cytokine levels were increased with MeHg exposure; however, in the subset of the population with elevated ANA, proinflammatory IL-1ß, IL-6, IFN-γ, and tumor necrosis factor (TNF)-α and anti-inflammatory (IL-4) cytokine levels were decreased with MeHg exposure. Although Se status was associated with MeHg level (correlation coefficient = 0.86; 95% CI: 0.29, 1.43), Se status was not associated with any changes in ANA and did not modify associations between Hg and ANA titers. CONCLUSIONS: MeHg exposure was associated with an increased ANA and changes in serum cytokine profile. Moreover, alterations in serum cytokine profiles differed based on ANA response, suggesting a specific phenotype of MeHg susceptibility. Further research on the potential health implications of these observed immunological changes is warranted.
Assuntos
Biomarcadores/sangue , Exposição Ambiental , Poluentes Ambientais/metabolismo , Peixes/metabolismo , Imunotoxinas/metabolismo , Compostos de Metilmercúrio/metabolismo , Selênio/metabolismo , Animais , Anticorpos Antinucleares/sangue , Autoanticorpos/sangue , Brasil , Estudos Transversais , Citocinas/sangue , Poluentes Ambientais/sangue , Poluentes Ambientais/urina , Humanos , Imunotoxinas/sangue , Imunotoxinas/urina , Compostos de Metilmercúrio/sangue , Compostos de Metilmercúrio/urina , Razão de ChancesRESUMO
Selenium (Se) is a well-known anti-oxidant with a critical role in the proper functioning of nervous and muscle functions. Se deficiency has been associated with both cognitive and neuromotor impairment, while sensory and motor deficits have been attributed to excess Se. In the Lower Tapajós Region of the Brazilian Amazon, riverside populations present a wide range of Se levels. These fish-eating communities have among the highest mercury (Hg) exposures reported in the world today, and recently, lead (Pb) exposure has been identified. Some studies suggest that Se intake can be protective for Hg and/or Pb toxicity, however, data from animal and human studies are inconsistent. The objective of the present study was to examine the relations between biomarkers of Se and motor functions, taking into account co-variables and biomarkers of exposure to Hg and Pb. Participants (n=448), aged 15-87 y, were recruited from 12 communities along the Tapajós River. Se concentrations were measured in whole blood (B-Se), plasma (P-Se), hair (H-Se) and urine (U-Se) by ICP-MS. Whole blood Hg (B-Hg) and Pb (B-Pb) were also measured by ICP-MS. Interview-administered questionnaires served to collect information on socio-demographics and medical history. All participants underwent a complete visual examination and performed tests of motor functions (Branches Alternate Movement Task, Santa Ana Test, Dynamometer and Grooved Pegboard Test). B-Se varied from 103 to 1500 µg/L (median 228 µg/L), P-Se from 53.6 to 913 µg/L (median 135 µg/L), H-Se from 0.4 to 3.8 µg/g (median 0.7 µg/g) and U-Se from 2.3 to 1375 µg/g cr. (median 33.6 µg/g cr.). Median B-Hg and B-Pb levels were 42.5 µg/L and 113 µg/L respectively. In multivariable analysis, Se biomarkers (log-transformed) were positively related to better performance on all motor tests, taking into account socio-demographic co-variables and B-Hg and B-Pb levels. P-Se consistently showed stronger associations to motor performance compared to the other Se biomarkers. Regression estimates for Se biomarkers were considerably stronger when controlling for B-Hg. When stratifying at the median for B-Hg concentrations, P-Se consistently presented associations with the outcomes only at high B-Hg concentrations. This is the first human study to report beneficial effects of high Se status on motor functions. For this population with elevated Hg exposure, high dietary Se intake may be critical for brain and muscle functions. However, these findings are not necessarily applicable to populations with lower Hg exposure and/or Se status, which is the case for people who do not rely heavily on fish consumption, be they in Brazil, the United States or elsewhere. The associations were mostly observed with P-Se, suggesting that P-Se or plasma selenoproteins may be good biomarkers for these outcomes.
Assuntos
Dieta , Poluentes Ambientais/efeitos adversos , Contaminação de Alimentos , Chumbo/efeitos adversos , Mercúrio/efeitos adversos , Atividade Motora/efeitos dos fármacos , Alimentos Marinhos/efeitos adversos , Selênio/análise , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Análise de Variância , Biomarcadores/análise , Brasil , Distribuição de Qui-Quadrado , Estudos Transversais , Ecossistema , Poluentes Ambientais/sangue , Feminino , Cabelo/química , Humanos , Chumbo/sangue , Modelos Lineares , Masculino , Espectrometria de Massas , Mercúrio/sangue , Pessoa de Meia-Idade , Testes Neuropsicológicos , Rios , Selênio/sangue , Selênio/urina , Inquéritos e Questionários , Adulto JovemRESUMO
BACKGROUND: Age-related cataracts (ARCs) are an important cause of blindness in developing countries. Although antioxidants may be part of the body's defense to prevent ARC, environmental contaminants may contribute to cataractogenesis. In fish-eating populations of the lower Tapajós region, elevated exposure to mercury (Hg) has been reported, and blood levels of selenium (Se) range from normal to very high (> 1,000 microg/L). OBJECTIVES: We examined ARCs in relation to these elements among adults (> or = 40 years of age) from 12 riverside communities. METHODS: Participants (n = 211) provided blood samples and underwent an extensive ocular examination. Inductively coupled plasma mass spectrometry was used to assess Hg and Se in blood and plasma. RESULTS: One-third (n = 69; 32.7%) of the participants had ARC. Lower plasma Se (P-Se; < 25th percentile, 110 microg/L) and higher blood Hg (B-Hg; > or = 25th percentile, 25 microg/L) were associated with a higher prevalence odds ratio (POR) of ARC [adjusted POR (95% confidence interval), 2.69 (1.11-6.56) and 4.45 (1.43-13.83), respectively]. Among participants with high P-Se, we observed a positive but nonsignificant association with high B-Hg exposure, whereas among those with low B-Hg, we observed no association for P-Se. However, compared with the optimum situation (high P-Se, low B-Hg), the POR for those with low P-Se and high B-Hg was 16.4 (3.0-87.9). This finding suggests a synergistic effect. CONCLUSION: Our results suggest that persons in this population with elevated Hg, the cataractogenic effects of Hg may be offset by Se. Because of the relatively small sample size and possible confounding by other dietary nutrients, additional studies with sufficient power to assess multiple nutrient and toxic interactions are required to confirm these findings.
Assuntos
Catarata/epidemiologia , Dieta/estatística & dados numéricos , Compostos de Metilmercúrio/sangue , Selênio/sangue , Poluentes Químicos da Água/sangue , Adulto , Fatores Etários , Idoso , Idoso de 80 Anos ou mais , Antioxidantes/metabolismo , Brasil/epidemiologia , Exposição Ambiental/análise , Exposição Ambiental/estatística & dados numéricos , Feminino , Humanos , Modelos Logísticos , Masculino , Compostos de Metilmercúrio/toxicidade , Pessoa de Meia-Idade , Análise Multivariada , Razão de Chances , Poluentes Químicos da Água/toxicidadeRESUMO
Selenium (Se) intake is generally from food, whose Se content depends on soil Se and plant accumulation. For humans, adequate Se intake is essential for several selenoenzymes. In the Lower Tapajós region of the Brazilian Amazon, Se status is elevated with large inter-community variability. Se intake in this region, where Hg exposure is among the highest in the world, may be important to counteract mercury (Hg) toxicity. The present study was conducted in 2006 with 155 persons from four communities of the Lower Tapajós. The objectives were: i) to evaluate Se content in their typical diet and drinking water; ii) to compare food Se concentrations with respect to geographic location; and iii) to examine the contribution of consumption of different food items to blood Se. More than 400 local foods and 40 drinking water samples were collected. Participants responded to an interview-administered food frequency questionnaire and provided blood samples. Food, water and blood Se levels were assessed by ICP-MS. Since Brazil nuts may also contain significant levels of barium (Ba) and strontium (Sr), these elements were likewise analyzed in nuts. The highest Se concentrations were found in Brazil nuts, but concentrations were highly variable (median: 13.9 microg/g; range: 0.4-158.4 microg/g). Chicken, game meat, eggs and beef also contained considerable levels of Se, with median concentrations from 0.3 to 1.4 microg/g. There was no particular geographic distribution of food Se. Se concentration in drinking water was very low (< 1.4 microg/L). Blood Se covered a (103-1500 microg/L), and was positively related to regular consumption of Brazil nuts, domestic chicken and game meat. Brazil nuts were found to contain highly variable and often very high concentrations of Ba (88.0 microg/g, 1.9-1437 microg/g) and Sr (38.7 microg/g, 3.3-173 microg/g).
Assuntos
Dieta , Exposição Ambiental/análise , Monitoramento Ambiental , Poluentes Ambientais/metabolismo , Rios/química , Selênio/metabolismo , Brasil , Ingestão de Alimentos , Exposição Ambiental/estatística & dados numéricos , Poluentes Ambientais/análise , Alimentos/estatística & dados numéricos , Selênio/sangue , Poluentes Químicos da Água/análise , Poluentes Químicos da Água/metabolismo , Abastecimento de Água/análiseRESUMO
Mercury (Hg) contamination in the Brazilian Amazon constitutes a serious environmental and public health issue. This study is part of the CARUSO Project, which uses an ecosystem approach to human health to examine the sources, transmission, and effects of Hg in the Brazilian Amazon, with a view to developing preventive intervention strategy. To date, studies have focused on measures of Hg exposure through fish consumption in relation to health effects; little attention has been given to quality of life (QoL). The objective of this study was to examine the relations between QoL and health perceptions, Hg exposure, sociodemographics, living conditions, and lifestyle in communities along the Tapajós River. A total of 456 adults from 13 villages were interviewed and provided hair samples for Hg analysis. Results showed that perceptions of QoL and health are relatively positive, despite elevated Hg exposure. Logistic regression analyses showed that a positive perception of QoL was associated with the absence of chronic illnesses, not smoking, fruit consumption, residing on the banks of the Tapajós, and living in an in-migrants' community. The positive perception of health was associated with younger age, the absence of reported symptoms of chronic illnesses, and drinking alcoholic beverages. Cluster analysis revealed that the group that reported the highest QoL had a traditional lifestyle, involving daily fishing and high fish consumption. However, this traditional lifestyle is associated with elevated Hg levels and early reported symptoms potentially linked to Hg exposure. These findings underline the importance of understanding the factors underlying QoL to develop adequate strategies to reduce Hg exposure and promote well-being.
Assuntos
Dieta , Peixes , Contaminação de Alimentos/análise , Nível de Saúde , Mercúrio/análise , Qualidade de Vida/psicologia , Adolescente , Adulto , Idoso , Animais , Brasil , Análise por Conglomerados , Estudos Transversais , Ecossistema , Feminino , Humanos , Estilo de Vida , Masculino , Pessoa de Meia-Idade , Percepção , Poluentes Químicos da Água/análise , Adulto JovemRESUMO
Mercury (Hg) exposure causes health problems that may result from increased oxidative stress and matrix metalloproteinase (MMP) levels. We investigated whether there is an association between the circulating levels of MMP-2, MMP-9, their endogenous inhibitors (the tissue inhibitors of metalloproteinases; TIMPs) and the circulating Hg levels in 159 subjects environmentally exposed to Hg. Blood and plasma Hg were determined by inductively coupled plasma-mass spectrometry (ICP-MS). MMP and TIMP concentrations were measured in plasma samples by gelatin zymography and ELISA respectively. Thiobarbituric acid-reactive species (TBARS) were measured in plasma to assess oxidative stress. Selenium (Se) levels were determined by ICP-MS because it is an antioxidant. The relations between bioindicators of Hg and the metalloproteinases levels were examined using multivariate regression models. While we found no relation between blood or plasma Hg and MMP-9, plasma Hg levels were negatively associated with TIMP-1 and TIMP-2 levels, and thereby with increasing MMP-9/TIMP-1 and MMP-2/TIMP-2 ratios, thus indicating a positive association between plasma Hg and circulating net MMP-9 and MMP-2 activities. These findings provide a new insight into the possible biological mechanisms of Hg toxicity, particularly in cardiovascular diseases.