Chronologically matched toenail-Hg to hair-Hg ratio: temporal analysis within the Japanese community (U.S.).

BACKGROUND: Toenail-Hg levels are being used as a marker of methylmercury (MeHg) exposure in efforts to associate exposure with effects such as cardiovascular disease. There is a need to correlate this marker with more established biomarkers that presently underlie existing dose-response relationships in order to compare these relationships across studies. METHODS: As part of the Arsenic Mercury Intake Biometric Study, toenail clippings were collected at three time points over a period of one year amongst females from within the population of Japanese living near Puget Sound in Washington State (US). Variability in temporal intra-individual toenail-Hg levels was examined and chronologically matched hair and toenail samples were compared to more accurately define the toxicokinetic variability of Hg levels observed between the two compartments. RESULTS: Mean toenail-Hg values (n=43) for the 1st, 2nd and 3rd visits were 0.60, 0.60 and 0.56 ng/mg. Correlations were as follows: r=0.92 between 1st and 2nd clinic visits, r=0.75 between 1st and 3rd visits and r=0.87 between 2nd and 3rd visits. With few exceptions, toenail-Hg values from any visit were within 50-150% of the individual's mean toenail-Hg level. Nearly all participants had less than a two-fold change in toenail-Hg levels across the study period. A regression model of the relationship between toenail-Hg and hair-Hg (n = 41) levels representing the same time period of exposure, gave a slope (Hg ng/mg) of 2.79 for hair relative to toenail (r=0.954). CONCLUSIONS: A chronologically matched hair-Hg to toenail-Hg ratio has been identified within a population that consumes fish regularly and in quantity. Intra-individual variation in toenail-Hg levels was less than two-fold and may represent dietary-based fluctuations in body burden for individuals consuming various fish species with different contaminant levels. The chronologically matched ratio will be useful for relating MeHg exposure and dose-response derived from toenail-Hg measurements to those derived from hair-Hg measurements in other studies, and may be useful in future investigations as an indicator of stable MeHg body burden within a population.

Single blood-Hg samples can result in exposure misclassification: temporal monitoring within the Japanese community (United States).

BACKGROUND: The most prominent non-occupational source of exposure to methylmercury is the consumption of fish. In this study we examine a fish consuming population to determine the extent of temporal exposure and investigate the extent to which single time estimates of methylmercury exposure based on blood-Hg concentration can provide reliable estimates of longer-term average exposure. METHODS: Blood-mercury levels were obtained from a portion of the Arsenic Mercury Intake Biometric Study (AMIBS) cohort. Specifically, 56 Japanese women residing in the Puget Sound area of Washington State, US were sampled on three occasions across a one-year period. RESULTS: An average of 135 days separated samples, with mean blood-mercury levels for the visits being 5.1, 6.6 and 5.0 µg/l and geometric means being 2.7, 4.5 and 3.1 µg/l. The blood-mercury levels in this group exceed national averages with geometric means for two of the visits being between the 90th and 95th percentiles of nationally observed levels and the lowest geometric mean being between the 75th and 90th percentile. Group means were not significantly different across sampling periods suggesting that exposure of combined subjects remained relatively constant. Comparing intra-individual results over time did not reveal a strong correlation among visits (r = 0.19, 0.50, 0.63 between 1st and 2nd, 2nd and 3rd, and 1st and 3rd sample results, respectively). In comparing blood-mercury levels across two sampling interval combinations (1st and 2nd, 2nd and 3rd, and 1st and 3rd visits, respectively), 58% (n = 34), 53% (n = 31) and 29% (n = 17) of the individuals had at least a 100% difference in blood-Hg levels. CONCLUSIONS: Point estimates of blood-mercury, when compared with three sample averages, may not reflect temporal variability and individual exposures estimated on the basis of single blood samples should be treated with caution as indicators of long-term exposure. Reliance on single blood samples can make predicting ongoing methylmercury exposure highly speculative due to the large intra-individual variability.

Comparative analysis of state fish consumption advisories targeting sensitive populations.

OBJECTIVE: Fish consumption advisories are issued to warn the public of possible toxicological threats from consuming certain fish species. Although developing fetuses and children are particularly susceptible to toxicants in fish, fish also contain valuable nutrients. Hence, formulating advice for sensitive populations poses challenges. We conducted a comparative analysis of advisory Web sites issued by states to assess health messages that sensitive populations might access. DATA SOURCES: We evaluated state advisories accessed via the National Listing of Fish Advisories issued by the U.S. Environmental Protection Agency. DATA EXTRACTION: We created criteria to evaluate advisory attributes such as risk and benefit message clarity. DATA SYNTHESIS: All 48 state advisories issued at the time of this analysis targeted children, 90% (43) targeted pregnant women, and 58% (28) targeted women of childbearing age. Only six advisories addressed single contaminants, while the remainder based advice on 2-12 contaminants. Results revealed that advisories associated a dozen contaminants with specific adverse health effects. Beneficial health effects of any kind were specifically associated only with omega-3 fatty acids found in fish. CONCLUSIONS: These findings highlight the complexity of assessing and communicating information about multiple contaminant exposure from fish consumption. Communication regarding potential health benefits conferred by specific fish nutrients was minimal and focused primarily on omega-3 fatty acids. This overview suggests some lessons learned and highlights a lack of both clarity and consistency in providing the breadth of information that sensitive populations such as pregnant women need to make public health decisions about fish consumption during pregnancy.

Linking the oceans to public health: current efforts and future directions.

We review the major linkages between the oceans and public health, focusing on exposures and potential health effects due to anthropogenic and natural factors including: harmful algal blooms, microbes, and chemical pollutants in the oceans; consumption of seafood; and flooding events. We summarize briefly the current state of knowledge about public health effects and their economic consequences; and we discuss priorities for future research.We find that:* There are numerous connections between the oceans, human activities, and human health that result in both positive and negative exposures and health effects (risks and benefits); and the study of these connections comprises a new interdisciplinary area, "oceans and human health."* The state of present knowledge about the linkages between oceans and public health varies. Some risks, such as the acute health effects caused by toxins associated with shellfish poisoning and red tide, are relatively well understood. Other risks, such as those posed by chronic exposure to many anthropogenic chemicals, pathogens, and naturally occurring toxins in coastal waters, are less well quantified. Even where there is a good understanding of the mechanism for health effects, good epidemiological data are often lacking. Solid data on economic and social consequences of these linkages are also lacking in most cases.* The design of management measures to address these risks must take into account the complexities of human response to warnings and other guidance, and the economic tradeoffs among different risks and benefits. Future research in oceans and human health to address public health risks associated with marine pathogens and toxins, and with marine dimensions of global change, should include epidemiological, behavioral, and economic components to ensure that resulting management measures incorporate effective economic and risk/benefit tradeoffs.

Mercury exposure from fish consumption within the Japanese and Korean communities.

Public health guidance pertaining to fish consumption requires that we be cognizant of the health concerns associated with eating contaminated fish and the nutritional benefits obtained from fish consumption. In doing so, a need exists for an improved understanding of the extent of contamination within various fish species consumed by populations of concern and the extent of exposure to contamination by these populations. As part of the Arsenic Mercury Intake Biometric Study involving the Japanese and Korean communities, it was possible to obtain fish intake data, determine mercury (Hg) fish tissue concentrations for various species consumed, and examine hair for Hg levels of study participants. This longitudinal study (n = 214) included 106 Japanese and 108 Korean women of childbearing age. Hair Hg levels for the two populations and weight-normalized, species-specific, individual-consumption pattern data that estimated Hg intake levels were compared with published National Health and Nutrition Examination Survey (NHANES) data. Sensitivity analyses and population-specific probabilistic assessments of exposure were conducted. The estimated Hg intake levels for the Japanese (0.09 microg/kg/d) and Koreans (0.05 microg/kg/d) were above the NHANES estimates (0.02 microg/kg/d), as were the hair Hg levels (1.23, 0.61, 0.2 ppm, respectively). Results indicate that (1) there are significant differences between the fish-species-consumption behavior of these two populations; (2) even when fish-consumption rates are equal between two populations, Hg intakes between them can vary significantly; and (3) these population and Hg intake differences present public health challenges when attempting to provide fish consumption guidance.

Higher satiety ratings following yogurt consumption relative to fruit drink or dairy fruit drink.

OBJECTIVES: To compare the satiating power of semisolid and liquid yogurts with fruit beverages and dairy fruit drinks. DESIGN AND PROCEDURES: Thirty-two volunteers (16 men and 16 women), ages 18 to 35 years, consumed a 200-kcal preload stimulus on four separate occasions. A tray lunch was presented 90 minutes after the preload and food consumption was measured. METHODS: The stimuli were: a semisolid yogurt containing pieces of peach and eaten with a spoon (378 g), the same yogurt in a drinkable homogenized form (378 g), a peach-flavored dairy beverage (400 mL), and a peach juice beverage (400 mL). Participants rated hunger, thirst, satiety, and desire to eat at baseline and at 20-minute intervals after ingestion. RESULTS: The two yogurts (semisolid and liquid) led to lower hunger and higher fullness ratings as compared with the fruit drink or dairy fruit drink. There was no difference in satiety profiles between the yogurt that was eaten with a spoon and the drinkable version. Energy intakes at lunch were the same across all four conditions (mean+/-standard deviation, 806+/-43 kcal). CONCLUSIONS: The two yogurts were more satiating than the two beverages. However, lower hunger and higher fullness ratings after yogurt consumption did not lead to energy compensation at the next meal.

Longitudinal mercury monitoring within the Japanese and Korean communities (United States): implications for exposure determination and public health protection.

BACKGROUND: Estimates of exposure to toxicants are predominantly obtained from single time-point data. Fish consumption guidance based on these data may be incomplete, as recommendations are unlikely to consider impact from factors such as intraindividual variability, seasonal differences in consumption behavior, and species consumed. OBJECTIVES/METHODS: We studied populations of Korean (n = 108) and Japanese (n = 106) women living in the Puget Sound area in Washington State to estimate mercury exposure based on fish intake and hair Hg levels at two and three time points, respectively. Our goals were to examine changes in hair Hg levels, fish intake behavior, and Hg body burden over time; and to determine if data from multiple time points could improve guidance. RESULTS/CONCLUSION: More than 50 fish species were consumed, with eight species representing approximately three-fourths of fish consumed by the Japanese and 10 species representing approximately four-fifths of fish intake by the Koreans. Fish species responsible for most Hg intake did not change over time; < 10 species accounted for most of the Hg body burden in each population. Longitudinal variability of hair Hg levels changed slowly across the study period. Japanese with hair Hg levels > 1.2 ppm (mean, 2.2 ppm) consumed approximately 150% more fish than those with levels < or = 1.2 ppm (mean, 0.7 ppm). However, because many participants consumed substantial amounts of fish while having hair-Hg levels < or = 1.2 ppm, the nutritional benefits offered from fish consumption should be obtainable without exceeding the RfD. We observed a 100% difference in fish intake between open-ended and 2-week recall fish consumption surveys. Open-ended survey data better represent Hg intake as determined from hair Hg levels. Single time-point fish intake data appear to be adequate for deriving guidance, but caution is warranted, as study is required to determine the significance of the different outcomes observed using the two survey time frames.

Arsenic exposure within the Korean community (United States) based on dietary behavior and arsenic levels in hair, urine, air, and water.

BACKGROUND: Determining arsenic exposure in groups based on geographic location, dietary behaviors, or lifestyles is important, as even moderate exposures may lead to health concerns. OBJECTIVES/METHODS: The Korean community in Washington State, represents a group warranting investigation, as they consume foods (e.g., shellfish, rice, finfish, and seaweed) known to contain arsenic. As part of the Arsenic Mercury Intake Biometric Study, we examined the arsenic levels in hair and urine along with the diets of 108 women of childbearing age from within this community. Arsenic levels in indoor air and drinking water were also investigated, and shellfish commonly consumed were collected and analyzed for total and speciated arsenic. RESULTS: The six shellfish species analyzed (n = 667) contain total arsenic (range, 1-5 microg/g) but are a small source of inorganic arsenic (range, 0.01-0.12 microg/g). Six percent of the individuals may have elevated urinary inorganic arsenic levels (> 10 microg/L) due to diet. Seaweed, rice, shellfish, and finfish are principal sources for total arsenic intake/excretion based on mass balance estimates. Rice consumption (163 g/person/day) may be a significant source of inorganic arsenic. Air and water are not significant sources of exposure. Hair is a poor biometric for examining arsenic levels at low to moderate exposures. CONCLUSIONS: We conclude that a portion of this community may have dietary inorganic arsenic exposure resulting in urine levels exceeding 10 microg/L. Although their exposure is below that associated with populations exposed to high levels of arsenic from drinking water (> 100 microg/L), their exposure may be among the highest in the United States.

Fish intake guidelines: incorporating n-3 fatty acid intake and contaminant exposure in the Korean and Japanese communities.

BACKGROUND: Fish consumption advisories are developed to prevent overexposure to various contaminants. Recently, discussion has centered on the need to consider the benefits of fish consumption alongside possible risks when providing guidance. OBJECTIVE: As part of the Arsenic Mercury Intake Biometric Study involving the Japanese and Korean communities living in Washington State, we obtained fish and nutrient intake data. Japanese and Korean women of childbearing age (n = 214) participated in this longitudinal study. We used these data, along with hair-mercury data to determine the need for both the nutritional benefits and concern about contaminants to be included when providing guidance. DESIGN: We examined the intake of 2 n-3 long-chain fatty acids, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), found in fish and associated with a variety of beneficial health effects. Intakes of these lipids were used as surrogates to characterize the beneficial effect from fish consumption, and the intake of mercury was used to establish the risk from consumption. RESULTS: These 2 populations provided an ideal basis from which to examine this issue because their fish consumption rates were identical and higher than national rates, but their mercury intakes vary substantially because of different consumption behaviors. Results indicate that basing fish consumption guidelines on contaminant concentrations alone can have the unintended consequence of causing a portion of the population to have inadequate intake of required nutrients. CONCLUSION: Public health goals may be better served if nutritional elements and contaminant concerns are quantitatively incorporated into fish consumption guidelines.