An approach for quantitatively balancing methylmercury risk and omega-3 benefit in fish consumption advisories

Exposome-wide association study of cognition among older adults in the National Health and Nutrition Examination Survey

Cognitive impairment among older adults is a growing public health challenge and environmental chemicals may be modifiable risk factors. A wide array of chemicals has not yet been tested for association with cognition in an environment-wide association framework. In the US National Health and Nutrition Examination Survey (NHANES) 1999-2000 and 2011-2014 cross-sectional cycles, cognition was assessed using the Digit Symbol Substitution Test (DSST, scores 0-117) among participants aged 60 years and older. Concentrations of environmental chemicals measured in blood or urine were log2 transformed and standardized. Chemicals with at least 50% of measures above the lower limit of detection were included (nchemicals=147, nclasses=14). We tested for associations between chemical concentrations and cognition using parallel survey-weighted multivariable linear regression models adjusted for age, sex, race/ethnicity, education, smoking status, fish consumption, cycle year, urinary creatinine, and cotinine. Participants with at least one chemical measurement (n=4,982) were mean age 69.8 years, 55.0% female, 78.2% non-Hispanic White, and 77.0% at least high school educated. The mean DSST score was 50.4 (standard deviation (SD)=17.4). In adjusted analyses, 5 of 147 exposures were associated with DSST at p-value<0.01. Notably, a SD increase in log2-scaled cotinine concentration was associated with 2.71 points lower DSST score (95% CI -3.69, -1.73). A SD increase in log2-scaled urinary tungsten concentration was associated with 1.34 points lower DSST score (95% CI -2.11, -0.56). Exposure to environmental chemicals, particularly heavy metals and tobacco smoke, may be modifiable factors for cognition among older adults.

Mercury exposure in the Norwegian Mother, Father, and Child Cohort Study - measured and predicted blood concentrations and associations with birth weight

Background

Blood total mercury concentration (BTHg) predominantly contains methyl Hg from seafood, and less inorganic Hg. Measured BTHg is often available only in a small proportion of large cohort study samples. Associations between estimated dietary intake of total Hg (THg) and lower birth weight within strata of maternal seafood intake was previously reported in the Norwegian Mother, Father, and Child Cohort Study (MoBa). However, maternal seafood consumption was associated with increased birth weight, indicating negative confounding by seafood in the association between THg intake and birth weight. Using predicted BTHg as a proxy for measured BTHg, we hypothesized that predicted BTHg would be associated with decreased birth weight.

Objectives

To develop and validate a prediction model for BTHg in MoBa and to examine the association between predicted BTHg and birth weight in the MoBa population.

Methods

Using linear regression, measured maternal BTHg (n = 1437) was used to build the best fitting model (highest R-squared value). Model validation (n = 1436) was based on correlation and weighted Kappa (Кw). Associations between predicted BTHg in the MoBa population (n = 86,775) or measured BTHg (n = 3590) and birth weight were assessed by multivariate linear regression models.

Results

The best fitting model had R-squared = 0.3 and showed strong correlation (r = 0.53, p < 0.001) between predicted and measured BTHg. Cross-classification (quintiles) showed 73 % correctly classified and 3.3 % grossly misclassified, with Кw of 0.37. Measured BTHg was not associated with birth weight. Predicted BTHg was significantly associated with higher birth weight. There were no trends in birth weight with increasing quintiles of measured or predicted BTHg after stratification into high or low seafood consumption.

Conclusions

The results indicate that prediction of BTHg did not overcome negative confounding of the association between Hg exposure and birth weight by seafood intake. Furthermore, effect on birth weight of toxicological concern is unexpected in our observed BTHg range.

Weight Changes, Nutritional Intake, Food Contaminants, and Supplements in Women of Childbearing Age, including Pregnant Women: Guidelines for Interventions during the Perinatal Period from the French National College of Midwives

Adequate maternal nutrition is crucial for a healthy pregnancy and optimal fetal growth. Many women in France of childbearing age start their pregnancy in an unfavorable nutritional status. Recent studies highlight the value of paying attention to weight issues from the preconceptional period. It is important to call attention to the need for folate supplementation and to promote a varied and balanced diet throughout pregnancy to cover essential nutritional needs.

Balancing the health effect between risks of methylmercury and benefits of nutrients in consumption of Chinese mitten crab (Eriocheir sinensis) in China

Aquatic products contain both beneficial substances such as polyunsaturated fatty acids and harmful compounds such as methylmercury, and their combined health effects should be assessed at a common end point for a rational analysis. We used a risk-benefit model to assess net IQ point gain from consumption of Chinese mitten crabs (Eriocheir sinensis) from Jiangsu Province. Levels of methylmercury in the edible parts of the crabs ranged from 0.79 to 69.47 μg/kg (mean: 26.88 ± 15.09 μg/kg). Levels of methylmercury did not differ by sampling location. In aquaculture experiments, we simulated artificial pond farming using either iced trash fish or formulated feed. Crabs fed iced trash fish contained 28.72 ± 2.30 mg/g of eicosapentaenoic acid and docosahexaenoic acid and crabs fed formulated feed contained 19.64 ± 3.62 mg/g of eicosapentaenoic acid and docosahexaenoic acid. Model calculations estimated a gain of 7.52 IQ points from consumption of crabs fed formulated feed and 11.00 IQ points from consumption of crabs fed iced trash fish. They are all above the maximum theoretical IQ point gain value. Chinese mitten crab is a kind of high-quality food which is beneficial to the neural development of infants. Our findings may assist in improving crab farming methods and consumption patterns, accelerating the sustainable development of the Chinese mitten crab industry.

Examining Links Between Diet and Lead Exposure in Young Children: 2009 to 2014 National Health and Nutrition Examination Survey

OBJECTIVE

Despite recommendations to consume iron-, calcium-, and vitamin C-rich foods for managing blood lead levels (BLLs), limited evidence exists on how specific foods affect children's BLLs. Using data from 12- to 36-month olds (n = 992) from the 2009 to 2014 National Health and Nutrition Examination Survey, we assessed how foods rich in these nutrients associate with BLLs, and with potential inadvertent exposures to cadmium and mercury.

METHODS

Food intake was assessed from one 24-hour dietary recall. Foods were categorized into 10 energy-adjusted groups, with intake categorized as none (reference) and tertiles. BLLs were natural log-transformed. Linear regressions tested associations between food groups and BLLs. Logistic regressions were conducted for blood cadmium and mercury.

RESULTS

Median (5%, 95% range) BLLs were 1.01 (0.39, 3.21) µg/dL. Majority of food groups (7 of 10) showed little association with BLLs. Compared to no intake, cereal (tertile 3: β [95% confidence interval] = -0.22 [-0.41, -0.02]) and milk (P_trend < 0.002; nonsignificant tertiles) consumption was associated with lower BLLs. Meat (tertile 2: 0.23 [0.01, 0.45]) and fruit drink (tertile 2: 0.20 [0.03, 0.38]; tertile 3: 0.25 [0.02, 0.49]) intake was associated with higher BLLs. Fruit drink consumption was associated with lower likelihood of having blood cadmium >0.11 µg/dL (tertile 3: odds ratio: 0.05 [0.01, 0.36]). No associations were observed with blood mercury.

CONCLUSIONS

Among young children, consumption of iron-, calcium-, and vitamin C-rich foods showed weak or no association with BLLs. Few associations were observed for blood cadmium or mercury. Food-based approaches to BLL management may have limited utility when exposure is low.

Current status of food safety hazards and health risks connected with aquatic food products from Southeast Asian region

Food safety issues associated with aquatic food products become more important with the increasing consumption and followed by its ongoing challenges. The objective of this paper is to review the food safety hazards and health risks related to aquatic food products for the Southeast Asian region. These hazards can be categorized as microplastics (MPs) hazard, biological hazards (pathogenic bacteria, biogenic amines, viruses, parasites), and chemical hazards (antimicrobial, formaldehyde, heavy metal). In different Southeast Asian countries, the potential health risks of aquatic food products brought by food hazards to consumers were at different intensity and classes. Among all these hazards, pathogenic bacteria, antimicrobials, and heavy metal were a particular concern in the Southeast Asian region. With environmental changes, evolving consumption patterns, and the globalization of trade, new food safety challenges are created, which put forward higher requirements on food technologies, food safety regulations, and international cooperation.

Risk-Benefit Modeling to Guide Health Research in Collaboration with Great Lakes Fish Consuming Native American Communities

It is well documented that fish consumption imparts both health risks and benefits. Furthermore, fish harvest and consumption are an essential part of Great Lakes Native American cultures. Quantitative models that compare risk and benefits to potential consumption scenarios can help guide future health research as well as consumption advice for potentially sensitive populations. This article presents fish consumption scenarios based on self-reported meal plans constructed by tribal members in eastern upper peninsula and northern lower Michigan Anishinaabe. Two risk-benefit models were applied to these scenarios to estimate the potential neurodevelopmental and cardiovascular risks (either increased or reduced risk) from dioxin-like polychlorinated biphenyls (DL-PCBs), methylmercury (MeHg), and omega-3 polyunsaturated fatty acids (n3-PUFA). All scenarios except maximum exposure estimates (i.e. 25^th-75^th percentile MeHg, DL-PCB, and n3-PUFA intakes) predicted reduced cardiovascular risk and improved neurodevelopmental outcomes. The greatest predicted benefits (adjusted for risks) occurred at the 75^th percentile intake of MeHg, DL-PCB, and n3-PUFA scenarios: 5.0 visual recall memory (VRM) and 4.41 Intelligence Quotient (IQ) benefits, and 28% reduced risk of cardio-vascular disease. Scenarios based on maximum self-reported intake, however, predicted health detriments. These results suggest that most fish consumption scenarios as constructed in collaboration with Native American communities could impart health benefits despite the presence of contaminants. However, high-end consumption estimates warrant caution as well as the need for well-crafted advice. Potential benefits further underscore the value of reducing contamination burdens in Great Lakes fisheries. Future priorities of ongoing contamination monitoring and health research are discussed.

Risk tradeoffs associated with traditional food advisories for Labrador Inuit

The traditional Inuit diet includes wild birds, fish and marine mammals, which can contain high concentrations of the neurotoxicant methylmercury (MeHg). Hydroelectric development may increase MeHg concentrations in traditional foods. Consumption advisories are often used to mitigate such risks and can result in reduced intake of traditional foods. Data from a dietary survey, MeHg exposure assessment and risk analysis for individuals in three Inuit communities in Labrador, Canada (n = 1145) in 2014 indicate reducing traditional food intake is likely to exacerbate deficiencies in n-3 polyunsaturated fatty acids and vitamins B12 and B2. Traditional foods accounted for < 5% of per-capita calories but up to 70% of nutrients consumed. Although consumption advisories could lower neurodevelopmental risks associated with an increase in MeHg exposure (90th-percentile ∆IQ = - 0.12 vs. - 0.34), they may lead to greater risks of cardiovascular mortality (90th-percentile increase: + 58% to + 116% vs. + 25%) and cancer mortality (90th-percentile increase + 2% to + 4% vs. no increase). Conversely, greater consumption of locally caught salmon mostly unaffected by hydroelectric flooding would lower all these risks (90th-percentile ∆IQ = + 0.4; cardiovascular risk: - 45%; cancer risk: - 1.4%). We thus conclude that continued consumption of traditional foods is essential for Inuit health in these communities.

Mercury, Polychlorinated Biphenyls, Selenium, and Fatty Acids in Tribal Fish Harvests of the Upper Great Lakes

The Chippewa Ottawa Resource Authority monitors fish contaminants in Anishinaabe (Great Lake Native American) tribal fisheries. This article updates previously reported trends in two persistent bioaccumulative toxic (PBT) substances that are the primary contributors to consumption advisory limits for these fish: methylmercury (MeHg) and polychlorinated biphenyls (PCBs). Also, we report, for the first time, an analysis of nutritional benefit bioindicators and metrics in these same Upper Great Lakes fish harvests: selenium (Se) and omega-3 fatty acids (PUFA-3s). A novel risk/benefit quantification originally presented by Ginsberg et al. is reported here to characterize the tradeoffs between fatty acid benefits and toxic MeHg health outcomes. We also report a Se benefit metric to characterize the possible protective value against MeHg neurotoxicity based on Ralston et al. Congruent with Anishinaabe cultural motivations to consume fish from their ancestral fisheries, nutritional content was high in locally caught fish and, in some respects, superior to farmed/store-bought fish. These Great Lakes fish still contained levels of PBTs that require careful education and guidance for consumers. However, the contaminant trends suggest that these fish need not be abandoned as important (both culturally and nutritionally) food sources for the Anishinaabe who harvested them.

Fish for Dinner? Balancing Risks, Benefits, and Values in Formulating Food Consumption Advice

Many and complex factors underlie seemingly simple decisions about what to eat. This is particularly so for foods such as fish, which present consumers with both risks and benefits. Advice about what type of and how much fish to consume is abundant, but that advice is often confusing or contradictory, reflecting the differing mandates and orientations of those advising. We survey a range of issues that can and should be incorporated into dietary advice, and offer tools for health agencies tasked with providing it. We argue that risks and benefits should not be limited to direct physical health. Rather, socioeconomic and community factors, unintended or indirect effects, and nonhuman-health outcomes such as animal welfare and planetary health should also be considered and weighed. We provide examples of existing fish consumption guidance to highlight the conflicting messages that emerge when different sources of advice with singular aims of avoiding risk, gaining nutritional benefit, or sustaining fish populations are juxtaposed. We then offer tools borrowed from health and other fields to guide health agencies toward developing more comprehensive advice and targeting that advice for specific populations.

Maternal intake of seafood and supplementary long chain n-3 poly-unsaturated fatty acids and preterm delivery

BACKGROUND

Preterm delivery increases the risk of neonatal morbidity and mortality. Studies suggest that maternal diet may affect the prevalence of preterm delivery. The aim of this study was to assess whether maternal intakes of seafood and marine long chain n-3 polyunsaturated fatty acids (LCn-3PUFA) from supplements were associated with preterm delivery.

METHODS

The study population included 67,007 women from the Norwegian Mother and Child Cohort Study. Maternal food and supplement intakes were assessed by a validated self-reported food frequency questionnaire in mid-pregnancy. Information about gestational duration was obtained from the Medical Birth Registry of Norway. We used Cox regression to estimate hazard ratios (HR) with 95% confidence intervals (CI) for associations between total seafood, lean fish, fatty fish, and LCn-3PUFA intakes and preterm delivery. Preterm was defined as any onset of delivery before gestational week 37, and as spontaneous or iatrogenic deliveries and as preterm delivery at early, moderate, and late preterm gestations.

RESULTS

Lean fish constituted 56%, fatty fish 34% and shellfish 10% of seafood intake. Any intake of seafood above no/rare intake (>5 g/d) was associated with lower prevalence of preterm delivery. Adjusted HRs were 0.76 (CI: 0.66, 0.88) for 1-2 servings/week (20-40 g/d), 0.72 (CI: 0.62, 0.83) for 2-3 servings/week (40-60 g/d), and 0.72 (CI: 0.61, 0.85) for ≥3 servings/week (>60 g/d), p-trend <0.001. The association was seen for lean fish (p-trend: 0.005) but not for fatty fish (p-trend: 0.411). The intake of supplementary LCn-3PUFA was associated only with lower prevalence of early preterm delivery (before 32 gestational weeks), while increasing intake of LCn-3PUFA from food was associated with lower prevalence of overall preterm delivery (p-trend: 0.002). Any seafood intake above no/rare was associated with lower prevalence of both spontaneous and iatrogenic preterm delivery, and with lower prevalence of late preterm delivery.

CONCLUSIONS

Any intake of seafood above no/rare consumption was associated with lower prevalence of preterm delivery. The association was stronger for lean than for fatty fish. Intake of supplementary LCn-3PUFA was associated only with early preterm delivery. The findings corroborate the current advice to include fish and seafood as part of a balanced diet during pregnancy.

Risk-benefit of consuming Lake Erie fish

BACKGROUND

Consumption of fish is promoted as a healthy way to obtain essential fatty acids (EFA) in the diet, yet the risk of ingesting harmful contaminants remains a concern. A recent study concluded that the risk-benefit of consuming fish from the North American Laurentian Great Lakes, which sustain important commercial and recreational fisheries, is currently unclear. We report the fatty acid (FA) content in skin-off fillets of fifteen fish species from Lake Erie and assess whether recommended dietary requirements for two EFA (EPA and DHA) can be met by safely consuming Lake Erie fishes, as an example of a risk-benefit analysis.

METHODS

A total of 146 samples were analyzed for FA and contaminant content. A simulated fish consumption advisory (maximum recommended number of meals per month, up to 32) was calculated for each sample, and used to calculate the maximum amount of EPA+DHA that would be consumed if the consumption advisory was followed.

RESULTS

All fifteen species had nutritionally desirable PUFA:SAFA (>0.4) and n-3:n-6 (>1). Large, fatty species had the highest EPA+DHA content, but had the most restrictive consumption advisories due to high PCB concentrations. To minimize contaminant exposure while maximizing EPA+DHA intake, consumers should consider small lake whitefish and lake trout, small panfish species, and/or walleye. However, very few species had an EPA+DHA content sufficient to safely meet the highest dietary guidelines while following advisories.

CONCLUSIONS

Consumption of certain Lake Erie fish, an important recreational and commercial fishery, within the limits of our simulated fish consumption advisories, can be a good supplemental source of beneficial n-3 long chain PUFA.

Assessment of dietary fish consumption in pregnancy: comparing one-, four- and thirty-six-item questionnaires

OBJECTIVE

Fish consumption influences a number of health outcomes. Few studies have directly compared dietary assessment methods to determine the best approach to estimating intakes of fish and its component nutrients, including DHA, and toxicants, including methylmercury. Our objective was to compare three methods of assessing fish intake.

DESIGN

We assessed 30 d fish intake using three approaches: (i) a single question on total fish consumption; (ii) a brief comprehensive FFQ that included four questions about fish; and (iii) a focused FFQ with thirty-six questions about different finfish and shellfish.

SETTING

Obstetrics practices in Boston, MA, USA.

SUBJECTS

Fifty-nine pregnant women who consumed ≤2 monthly fish servings.

RESULTS

Estimated intakes of fish, DHA and Hg were lowest with the one-question screener and highest with the thirty-six-item fish questionnaire. Estimated intake of DHA with the thirty-six-item questionnaire was 4·4-fold higher (97 v. 22 mg/d), and intake of Hg was 3·8-fold higher (1·6 v. 0·42 μg/d), compared with the one-question screener. Plasma DHA concentration was correlated with fish intake assessed with the one-question screener (Spearman r = 0·27, P = 0·04), but not with the four-item FFQ (r = 0·08, P = 0·54) or the thirty-six-item fish questionnaire (r = 0·01, P = 0·93). In contrast, blood and hair Hg concentrations were similarly correlated with fish and Hg intakes regardless of the assessment method (r = 0·35 to 0·52).

CONCLUSIONS

A longer questionnaire provides no advantage over shorter questionnaires in ranking intakes of fish, DHA and Hg compared with biomarkers, but estimates of absolute intakes can vary by as much as fourfold across methods.

Role of fruits, grains, and seafood consumption in blood cadmium concentrations of Jamaican children with and without Autism Spectrum Disorder

Human exposure to cadmium has adverse effects on the nervous system. Utilizing data from 110 age- and sex-matched case-control pairs (220 children) ages 2-8 years in Kingston, Jamaica, we compared the 75th percentile of blood cadmium concentrations in children with and without Autism Spectrum Disorder (ASD). In both univariable and multivariable Quantile Regression Models that controlled for potential confounding factors, we did not find any significant differences between ASD cases and typically developing (TD) controls with respect to the 75th percentile of blood cadmium concentrations, (P > 0.22). However, we found a significantly higher 75th percentile of blood cadmium concentrations in TD Jamaican children who consumed shellfish (lobsters, crabs) (P <0.05), fried plantain (P <0.01), and boiled dumpling (P <0.01). We also observed that children living in Jamaica have an arithmetic mean blood cadmium concentration of 0.16μg/L which is similar to that of the children in developed countries and much lower than that of children in developing countries. Although our results do not support an association between blood cadmium concentrations and ASD, to our knowledge, this study is the first to report levels of blood cadmium in TD children as well as those with ASD in Jamaica.

Environmental risk score as a new tool to examine multi-pollutants in epidemiologic research: an example from the NHANES study using serum lipid levels

Objective

A growing body of evidence suggests that environmental pollutants, such as heavy metals, persistent organic pollutants and plasticizers play an important role in the development of chronic diseases. Most epidemiologic studies have examined environmental pollutants individually, but in real life, we are exposed to multi-pollutants and pollution mixtures, not single pollutants. Although multi-pollutant approaches have been recognized recently, challenges exist such as how to estimate the risk of adverse health responses from multi-pollutants. We propose an “Environmental Risk Score (ERS)” as a new simple tool to examine the risk of exposure to multi-pollutants in epidemiologic research.

Methods and Results

We examined 134 environmental pollutants in relation to serum lipids (total cholesterol, high-density lipoprotein cholesterol (HDL), low-density lipoprotein cholesterol (LDL) and triglycerides) using data from the National Health and Nutrition Examination Survey between 1999 and 2006. Using a two-stage approach, stage-1 for discovery (n = 10818) and stage-2 for validation (n = 4615), we identified 13 associated pollutants for total cholesterol, 9 for HDL, 5 for LDL and 27 for triglycerides with adjustment for sociodemographic factors, body mass index and serum nutrient levels. Using the regression coefficients (weights) from joint analyses of the combined data and exposure concentrations, ERS were computed as a weighted sum of the pollutant levels. We computed ERS for multiple lipid outcomes examined individually (single-phenotype approach) or together (multi-phenotype approach). Although the contributions of ERS to overall risk predictions for lipid outcomes were modest, we found relatively stronger associations between ERS and lipid outcomes than with individual pollutants. The magnitudes of the observed associations for ERS were comparable to or stronger than those for socio-demographic factors or BMI.

Conclusions

This study suggests ERS is a promising tool for characterizing disease risk from multi-pollutant exposures. This new approach supports the need for moving from a single-pollutant to a multi-pollutant framework.

Can fish consumption advisories do better? Providing benefit and risk information to increase knowledge

Humans exposed to methylmercury (MeHg) can suffer from adverse health impacts, e.g., serious neurological damage; however, fish is also a good source of omega-3 fish oils which promotes infants' neurological development. Because eating fish is the primary mechanism of MeHg exposure, federal and state agencies issue fish consumption advisories to inform the public about the risks of eating contaminated fish. An advisory's purpose is to provide information to consumers to increase their knowledge of specific product attributes; however, the difficulty in communicating both the risks and benefits of eating fish leads readers of fish advisories to over-restrict their fish consumption. Because the effectiveness of fish consumption advisories are not often evaluated by states, we help fill this gap by evaluating the effectiveness of Maine's fish consumption advisory in terms of improving knowledge. The results suggest the advisory successfully increased women's knowledge of both the benefits and risks of consuming fish while pregnant. The advisory also increased their ability to differentiate fish by their MeHg content, knowledge of both low and high-MeHg fish and knowledge of detailed attributes of seemingly substitutable goods, such as white tuna, light tuna and pre-packaged salmon. People who did not read the advisory lack the knowledge of how to identify fish that provide: health benefits like Omega-3 fatty acids, or health risks like MeHg; reading the advisory reduces this lack of knowledge. Readers increased ability to make specific substitutions to minimize risk while maintaining the benefits of fish eating suggests the advisory has the potential of reducing MeHg-related health risks while avoiding the drop in fish consumption show in other studies.

Selenium and mercury molar ratios in commercial fish from New Jersey and Illinois: variation within species and relevance to risk communication

There is an emerging consensus that people consuming large amounts of fish with selenium:mercury ratios below 1 are at higher risk from mercury toxicity. As the relative amount of selenium increases compared to mercury, risk may be lowered, but it is unclear how much excess selenium is required. It would be useful if the selenium:mercury ratio was relatively consistent within a species, but this has not been the case in our studies of wild-caught fish. Since most people in developed countries and urban areas obtain their fish and other seafood commercially, we examined selenium:mercury molar ratios in commercial fish purchased in stores and fish markets in central New Jersey and Chicago. There was substantial interspecific and intraspecific variation in molar ratios. Across species the selenium:mercury molar ratio decreased with increasing mean mercury levels, but selenium variation also contributed to the ratio. Few samples had selenium:mercury molar ratios below 1, but there was a wide range in ratios, complicating the interpretation for use in risk management and communication. Before ratios can be used in risk management, more information is needed on mercury:selenium interactions and mutual bioavailability, and on the relationship between molar ratios and health outcomes. Further, people who are selenium deficient may be more at risk from mercury toxicity than others.

Associations of blood and urinary mercury with hypertension in U.S. adults: the NHANES 2003-2006

BACKGROUND

Few studies have examined the association between hypertension and mercury exposure in the general population. We examined cross-sectional associations between blood (mainly methylmercury) or urinary mercury (mainly inorganic mercury) and hypertension in representative U.S. adults and effect modifications by dietary omega-3 fatty acids and serum selenium.

METHODS

We examined 6607 adults aged 20 years or older, using the National Health and Nutrition Examination Survey (NHANES) from 2003/2004 to 2005/2006 (2201 adults were available for urinary mercury from NHANES 2003-2006; 2117 available for serum selenium from NHANES 2003-2004 aged 40 years or older). The average of omega-3 fatty acids from two 24-h recalls was calculated.

RESULTS

The weighted prevalence of hypertension was 32.2%. The geometric means (95% confidence intervals) of blood total and urinary mercury were 1.03 (0.95, 1.11)μg/L and 0.51 (0.47, 0.54)μg/L, respectively. The adjusted odds ratios for a doubling increase in blood mercury and urinary mercury were 0.94 (0.87 to 1.01) and 0.87 (0.78 to 0.99), respectively, after adjusting for potential confounders. The associations remained similar, even after adjusting for either omega-3 fatty acids or selenium or both. No significant effect modification by either omega-3 fatty acids or selenium was observed.

CONCLUSIONS

In this cross-sectional study of the U.S. general population, we found no association of hypertension with blood mercury but a suggestive inverse association with urinary mercury. Future prospective studies are warranted to confirm these findings.

Seafood consumption and blood mercury concentrations in Jamaican children with and without autism spectrum disorders

Mercury is a toxic metal shown to have harmful effects on human health. Several studies have reported high blood mercury concentrations as a risk factor for autism spectrum disorders (ASDs), while other studies have reported no such association. The goal of this study was to investigate the association between blood mercury concentrations in children and ASDs. Moreover, we investigated the role of seafood consumption in relation to blood mercury concentrations in Jamaican children. Based on data for 65 sex- and age-matched pairs (2-8 years), we used a General Linear Model to test whether there is an association between blood mercury concentrations and ASDs. After controlling for the child's frequency of seafood consumption, maternal age, and parental education, we did not find a significant difference (P = 0.61) between blood mercury concentrations and ASDs. However, in both cases and control groups, children who ate certain types of seafood (i.e., salt water fish, sardine, or mackerel fish) had significantly higher (all P < 0.05) geometric means blood mercury concentration which were about 3.5 times that of children living in the US or Canada. Our findings also indicate that Jamaican children with parents who both had education up to high school are at a higher risk of exposure to mercury compared to children with at least one parent who had education beyond high school. Based on our findings, we recommend additional education to Jamaican parents regarding potential hazards of elevated blood mercury concentrations, and its association with seafood consumption and type of seafood.

Risk trade-offs in fish consumption: a public health perspective

Fish consumption advisories instruct vulnerable consumers to avoid high mercury fish and to limit total fish intake to reduce neurotoxic risk. Consumption data from the U.S. suggest that nontarget consumers also respond to such advice. These consumers reduce exposure to mercury and other toxicants at the cost of reduction in cardioprotective fatty acids. We present a probabilistic model to assess these risk trade-offs. We use NHANES consumption data to simulate exposure to contaminants and nutrients in fish, employ dose-response relationships to convert exposure to health end points, and monetize them using benefit transfer. Our results suggest that newborns gained on average 0.033 IQ points from their mothers' compliance with the prominent FDA/EPA advisory. The welfare gain for a birth cohort is estimated at $386 million. This gain could be fully offset by increments in cardiovascular risk if 0.6% of consumers aged 40 and older reduced fish intake by one monthly meal until they reached the age of 60 or if 0.1% of them permanently reduced fish intake.

Myocardial infarction in relation to mercury and fatty acids from fish: a risk-benefit analysis based on pooled Finnish and Swedish data in men

BACKGROUND

Exposure to methylmercury from fish has been associated with increased risk of myocardial infarction (MI) in some studies. At the same time, marine n-3 (omega-3) PUFAs are an inherent constituent of fish and are regarded as beneficial. To our knowledge, no risk-benefit model on the basis of data on methylmercury, PUFA, and MI risk has yet been presented.

OBJECTIVE

The objective of this study was to describe how exposure to both marine n-3 PUFAs and methylmercury relates to MI risk by using data from Finland and Sweden.

DESIGN

We used matched case-control sets from Sweden and Finland that were nested in population-based, prospective cohort studies. We included 361 men with MI from Sweden and 211 men with MI from Finland. MI risk was estimated in a logistic regression model with the amount of mercury in hair (hair-Hg) and concentrations of n-3 PUFAs (EPA and DHA) in serum (S-PUFA) as independent variables.

RESULTS

The median hair-Hg was 0.57 μg/g in Swedish and 1.32 μg/g in Finnish control subjects, whereas the percentage of S-PUFA was 4.21% and 3.83%, respectively. In combined analysis, hair-Hg was associated with higher (P = 0.005) and S-PUFA with lower (P = 0.011) MI risk. Our model indicated that even a small change in fish consumption (ie, by increasing S-PUFA by 1%) would prevent 7% of MIs, despite a small increase in mercury exposure. However, at a high hair-Hg, the modeled beneficial effect of PUFA on MI risk was counteracted by methylmercury.

CONCLUSIONS

Exposure to methylmercury was associated with increased risk of MI, and higher S-PUFA concentrations were associated with decreased risk of MI. Thus, MI risk may be reduced by the consumption of fish high in PUFAs and low in methylmercury.

Which fish should I eat? Perspectives influencing fish consumption choices

BACKGROUND

Diverse perspectives have influenced fish consumption choices.

OBJECTIVES

We summarized the issue of fish consumption choice from toxicological, nutritional, ecological, and economic points of view; identified areas of overlap and disagreement among these viewpoints; and reviewed effects of previous fish consumption advisories.

METHODS

We reviewed published scientific literature, public health guidelines, and advisories related to fish consumption, focusing on advisories targeted at U.S. populations. However, our conclusions apply to groups having similar fish consumption patterns.

DISCUSSION

There are many possible combinations of matters related to fish consumption, but few, if any, fish consumption patterns optimize all domains. Fish provides a rich source of protein and other nutrients, but because of contamination by methylmercury and other toxicants, higher fish intake often leads to greater toxicant exposure. Furthermore, stocks of wild fish are not adequate to meet the nutrient demands of the growing world population, and fish consumption choices also have a broad economic impact on the fishing industry. Most guidance does not account for ecological and economic impacts of different fish consumption choices.

CONCLUSION

Despite the relative lack of information integrating the health, ecological, and economic impacts of different fish choices, clear and simple guidance is necessary to effect desired changes. Thus, more comprehensive advice can be developed to describe the multiple impacts of fish consumption. In addition, policy and fishery management interventions will be necessary to ensure long-term availability of fish as an important source of human nutrition.

Selenium and mercury molar ratios in saltwater fish from New Jersey: individual and species variability complicate use in human health fish consumption advisories

Balancing risk versus benefits to humans and other organisms from consuming fish is a national concern in the USA, as well as in many other parts of the world. Protecting public health is both a federal and state responsibility, and states respond by issuing fish consumption advisories, particularly for mercury. Recently it has been emphasized that the protective role of selenium against mercury toxicity depends on their molar ratios, which should be evaluated as an indication of selenium's protective capacity, and incorporated in risk assessments for fish consumption. However, there is no single "protective" ratio agreed upon. In this paper we examine the selenium:mercury (Se:Hg) molar ratios in a wide range of saltwater fish caught and eaten by recreational fishers along the New Jersey coast. We were particularly interested in interspecific and intraspecific variability, and whether the molar ratios were consistent within a species, allowing for its use in managing risk. The selenium-mercury molar ratio showed significant variation among and within fish species. The molar ratio decreased with the size of the fish species, decreased with the mercury levels, and within a fish species, the selenium:mercury ratio decreased with fish size. As an essential element, selenium undergoes some homeostatic regulation, but it is also highly toxic. Within species, mercury level tends to increase with size, accounting for the negative relationship between size and ratio. This variability may make it difficult to use the selenium:mercury molar ratio in risk assessment, risk management, and risk communication at this time, and more information is needed on how mercury and selenium actually interact and on the relationship between the molar ratios and health outcomes.

Risk-benefit evaluation of fish from Chinese markets: nutrients and contaminants in 24 fish species from five big cities and related assessment for human health

The risks and benefits of fish from markets in Chinese cities have not previously been fully evaluated. In the present study, 24 common fish species with more than 400 individual samples were collected from markets from five big Chinese cities in 2007. The main nutrients and contaminants were measured and the risk-benefit was evaluated based on recommended nutrient intakes and risk level criteria set by relevant authorities. The comprehensive effects of nutrients and contaminants in marine oily fish were also evaluated using the data of two related human dietary intervention trials performed in dyslipidemic Chinese men and women in 2008 and 2010, respectively. The results showed that concentrations of contaminants analyzed including DDT, PCB(7), arsenic and cadmium were much lower than their corresponding maximum limits with the exception of the mercury concentration in common carp. Concentrations of POPs and n-3 LCPUFA, mainly EPA and DHA, were positively associated with the lipid content of the fish. With a daily intake of 80-100g marine oily fish, the persistent organic pollutants in fish would not counteract the beneficial effects of n-3 LCPUFA in reducing cardiovascular disease (CVD) risk markers. Marine oily fish provided more effective protection against CVD than lean fish, particularly for the dyslipidemic populations. The risk-benefit assessment based on the present daily aquatic product intake in Chinese urban residents (44.9 and 62.3g for the average values for all cities and big cities, respectively) indicated that fish, particularly marine oily fish, can be regularly consumed to achieve optimal nutritional benefits from n-3 LCPUFA, without causing significant contaminant-related health risks. However, the potential health threat from contaminants in fish should still be emphasized for the populations consuming large quantities of fish, particularly wild fish.