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- Original Article Relationship between shark meat intake and blood mercury concentration in Korean adolescents
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Jeong A Chang1
, Jeong Woo Park2,3,*, Joon SaKong2,3 -
Annals of Occupational and Environmental Medicine 2026;38:e28.
DOI: https://doi.org/10.35371/aoem.2026.38.e28
Published online: July 13, 2026
1Department of Radiology, Seoul National University Bundang Hospital, Seongnam, Korea
2Department of Occupational and Environmental Medicine, Yeungnam University Medical Center, Daegu, Korea
3Department of Preventive Medicine and Public Health, Yeungnam University College of Medicine, Daegu, Korea
- *Corresponding author: Jeong Woo Park Department of Occupational and Environmental Medicine, Yeungnam University Medical Center, 170 Hyeonchung-ro, Nam-gu, Daegu 42415, Korea E-mail: pjw6671@ymc.yu.ac.kr
• Received: April 15, 2026 • Revised: July 1, 2026 • Accepted: July 2, 2026
© 2026 Korean Society of Occupational & Environmental Medicine
This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (https://creativecommons.org/licenses/by-nc/4.0/) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.
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Abstract
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Background Mercury exposure through seafood consumption poses health risks, yet limited research has examined shark meat—a large predatory fish still consumed in Korea—and its association with blood mercury levels in adolescents.
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Methods This cross-sectional study used data from the 3rd Korean National Environmental Health Survey (KoNEHS). Multiple linear and logistic regression analyses were performed to assess the association between shark meat intake and blood mercury levels and to estimate the odds ratios for exceeding the reference blood mercury level, adjusting for potential confounders.
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Results Of the 912 participants, 50 (5.5%) were identified as shark meat consumption group. Shark meat consumption was associated with higher blood mercury concentrations (β = 0.41; 95% confidence interval [CI]: 0.23–0.59), with the highest levels observed among those who consumed shark meat within the past 30 days (β = 1.19; 95% CI: 0.30–2.08), those who preferred shark meat (β = 0.67; 95% CI: 0.26–1.08), and those with higher annual intake (β = 0.71; 95% CI: 0.00–1.43). Shark meat consumers had substantially higher odds of exceeding the blood mercury reference level (≥5.8 µg/L; odds ratio: 35.84; 95% CI: 3.39–378.84), with an estimated attributable risk of 97.2% (95% CI: 70.5%–99.7%) and a population attributable risk of 65.7% (95% CI: 11.6%–95.4%). Of the estimated 25,740 (95% range: 11,905–54,913) adolescents aged 12–17 years potentially exceeding this threshold, approximately 16,911 (95% CI: 2,986–24,556) cases may be attributable to shark meat consumption, though these estimates should be interpreted cautiously given the wide confidence intervals.
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Conclusions Shark meat consumption was associated with elevated blood mercury levels in Korean adolescents. Targeted education on its potential health risks is needed to reduce unintended exposure, while maintaining the nutritional benefits of fish consumption.
BACKGROUND
Adolescents are more vulnerable to dietary exposure to environmental pollutants than adults, as they consume a greater amount of food relative to their body weight during periods of growth.1 The characteristic and sustained growth during adolescence confers a unique physiological susceptibility not observed in adults. This underscores the globally recognized imperative to protect adolescents from long-lasting environmental contaminants such as mercury.2 Environmental pollutants have been shown to interfere with endocrine regulation during puberty development through mechanisms such as tissue cytotoxicity, alterations in hormone concentrations, and interference with steroidogenesis pathways.3 Mercury, in particular, has been reported to exert neurotoxic effects on the developing adolescent nervous system.3,4
Fish contain a variety of nutrients essential for adolescent development, and moderate consumption of fish and shellfish is important for growth. However, consideration must be given to the risk of mercury accumulation in seafood, particularly in the form of methylmercury. Methylmercury is formed when inorganic mercury, released from various pollution sources, enters aquatic environments such as lakes, rivers, and oceans and is converted by aquatic bacteria.5 Due to biomagnification and bioaccumulation processes, higher trophic level marine predators tend to accumulate elevated concentrations of methylmercury. Mercury levels in these species can reach concentrations thousands to millions of times greater than those found in ambient water.6 Common examples of such large predatory fish include sharks, tuna, and swordfish. When these species are consumed as food, over 95% of the ingested methylmercury is absorbed through the gastrointestinal tract. Methylmercury forms complexes with the amino acid cysteine, which enables it to cross the blood–brain barrier and accumulate in the central nervous system, making the nervous system the most sensitive target organ of mercury exposure.7
Numerous epidemiological studies have investigated the effects of methylmercury exposure on children. One of the earliest reports of adverse effects in offspring related to maternal consumption of fish and shellfish during pregnancy was documented in New Zealand.8 In the Seychelles Child Development Study, an association was observed between prenatal exposure to methylmercury and decreased cognitive function.9,10 Similar findings were confirmed in a prospective cohort study conducted in the Faroe Islands, which assessed the impact of maternal seafood consumption on child health. The study reported that even low-level exposure to methylmercury during early developmental stages could lead to neurobehavioral deficits, including impairments in memory, attention, language, visuospatial abilities, and motor function.11 Notably, prenatal exposure to methylmercury was found to have lasting effects on the autonomic nervous system up to 14 years of age,4 highlighting the importance of considering not only childhood but also adolescent health outcomes in relation to mercury exposure.
In South Korea, nationwide data on mercury exposure among adolescents have been derived from the Korea National Health and Nutrition Examination Survey (KNHANES).12 However, this study has primarily identified general dietary intake, including consumption of fish and seafood, as the major route of mercury exposure without distinguishing specific high-risk fish species such as shark.
Shark meat, a representative large predatory fish in the marine ecosystem, is widely distributed under the name dombae-gi in the Gyeongsangbuk-do region of South Korea. In this area, it is regarded as a traditional food that is relatively accessible in households and is commonly consumed by family units, including children and adolescents. Given the potential for repeated and continuous consumption among adolescents, concerns have been raised regarding the bioaccumulation of mercury in this population.
Heo et al.13 reported that among 105 shark meat (dombae-gi) samples collected from traditional markets in the Gyeongsangbuk-do region, the geometric mean mercury concentration was 1.44 µg/g (range: 0.06–8.93 µg/g), and 77 samples exceeded the threshold of 1 µg/g. These findings indicate that shark meat containing elevated levels of mercury is being actively distributed in local markets. Consistent with this, individuals who consumed shark meat (dombae-gi) exhibited significantly higher blood mercury concentrations compared with those who did not consume shark meat in the Gyeongsangbuk-do region, suggesting that shark meat consumption is a major contributor to increased blood mercury levels.14
This issue is not confined to a specific region. To date, no study has examined the association between shark meat consumption and blood mercury concentrations among adolescents at the national level in Korea. Therefore, the present study was conducted to evaluate shark meat consumption, representing the consumption of a large predatory fish, and its impact on blood mercury concentrations among Korean adolescents. The ultimate aim is to provide scientific evidence to better characterize mercury exposure during adolescence and to inform future food safety management and public health policies.
METHODS
This study utilized data from the third Korean National Environmental Health Survey (KoNEHS), a nationwide biomonitoring program representing the general population of Korea. The third cycle of KoNEHS was conducted between 2015 and 2017. The target population included individuals aged 3 years and older residing in Korea. The sample size was determined based on the precision of estimates for major variables obtained in the second cycle, and participants were selected using a stratified two-stage cluster sampling method within a complex sampling design. A total of 6,167 individuals aged 3 years and older were surveyed from 233 regions and 183 childcare and educational institutions across the country. For this study, 912 adolescents aged 12 to 17 years who responded to the questionnaire on shark meat consumption and had available blood mercury concentration data were included in the analysis.
Participant characteristics included variables such as sex, age, smoking status, and the frequency of large fish and shellfish consumption. Variables related to shark meat consumption comprised consumption status, annual intake frequency, time since last consumption, and preference. Participants were classified into two groups based on shark meat consumption status: consumers and non-consumers. Annual consumption frequency was categorized into three groups: 3–6 times, 1–2 times, and 0 times (non-consumers). The time since last consumption was grouped into three groups: ≤30 days, 31–60 days, and >60 days. Preference for shark meat was categorized as “preferred,” “less preferred,” “not preferred,” and “does not consume.” Reference levels for blood mercury concentration were set at 15.0 µg/L, 5.8 µg/L, 5.0 µg/L, and 3.5 µg/L. The levels of 15.0 µg/L and 5.0 µg/L correspond to the Human Biomonitoring (HBM) II and HBM I value, respectively, as proposed by the German Federal Environmental Agency.15
HBM II indicates a concentration above which adverse health effects are possible and immediate exposure reduction is recommended, whereas HBM I indicates a level below which no harmful effects are expected. The threshold of 5.8 µg/L is based on the mercury concentration in umbilical cord blood corresponding to the U.S. Environmental Protection Agency’s reference dose of 0.1 µg/kg body weight/day. The 3.5 µg/L level is a recommended maternal blood mercury concentration, estimated based on the assumption that cord blood mercury levels are approximately 1.7 times higher than those in maternal blood.16,17
The characteristics of the participants were compared according to shark meat consumption by using χ2 tests. To compare blood mercury concentrations across participant characteristics by shark meat consumption status, independent t-tests and analysis of variance (ANOVA) were performed. Multiple linear regression analysis was conducted to evaluate the association between shark meat consumption and blood mercury levels, adjusting for potential confounders including sex, age, smoking status, and consumption of large fish and shellfish. A generalized linear model with a log-link function was additionally employed to estimate geometric mean blood mercury concentrations and their ratios across groups, given the skewed distribution of blood mercury levels. The odds ratios (ORs) for exceeding the reference level of blood mercury concentration according to shark meat consumption were calculated using logistic regression analysis. All analyses accounting for the KoNEHS complex survey design—stratified two-stage cluster sampling with participant weights—were performed using the svy prefix in Stata, which applies design-based variance estimation. All statistical analyses were performed using Stata version 18.1 (StataCorp., College Station, TX, USA).
The data used in this study were obtained from the 3rd KoNEHS, a publicly available dataset with all personally identifiable information removed prior to release. Ethical approval was granted by the Institutional Review Board of Yeungnam University (IRB No. 7002016-E-2025-134). As this study involved secondary analysis of publicly available, de-identified data, the requirement for informed consent was waived.
RESULTS
Table 1 presents the distribution of shark meat consumption according to participants’ characteristics. Among the 912 study participants, 50 participants (5.5%) reported consuming shark meat. Shark meat consumption differed significantly by age and frequency of big fish intake. Adolescents aged 15–17 years were more likely to consume shark meat than those aged 12–14 years (7.3% vs. 3.7%). Additionally, participants who consumed large predatory fish at least once a month reported a higher prevalence of shark meat consumption compared to those who rarely consumed large fish (8.5% vs. 3.3%). No significant differences in shark meat consumption were observed by sex, smoking status, obesity or the consumption of small pelagic fish, crab, seaweed, or shellfish.
Table 2 presents the geometric mean blood mercury concentrations according to shark meat consumption status and participant characteristics. The geometric mean blood mercury concentration among adolescents was 1.38 µg/L. Blood mercury levels were higher in the shark meat consumption group than in the non-consumption group (1.95 vs. 1.36 µg/L). Males exhibited significantly higher blood mercury levels than females (1.45 vs. 1.33 µg/L), and participants with obesity had higher levels than those without obesity (1.50 vs. 1.36 µg/L), regardless of shark meat consumption. Regarding seafood dietary variables, blood mercury levels were higher in the ≥1/month and ≥1/week groups compared with the rarely consuming group. In the non-consumption group, blood mercury levels increased with higher frequency of intake, and the associations were statistically significant except seaweed consumption. In the consumption group, blood mercury levels were often higher in the ≥1/month category compared with other groups, although these differences did not reach statistical significance.
Table 3 presents the geometric mean blood mercury concentration according to shark meat consumption habits and their association with log-transformed blood mercury concentrations using linear regression analysis. In the adjusted model, blood mercury levels were higher among adolescents who consumed shark meat compared with non-consumers (β = 0.41; 95% confidence interval [CI]: 0.23–0.59). Mercury concentrations were highest in participants who consumed shark meat within the past 30 days (β = 1.19; 95% CI: 0.30–2.08) and decreased with longer intervals since last consumption. Higher mercury levels were also observed with greater preference for shark meat, with significant associations in the less preferred (β = 0.47; 95% CI: 0.24–0.71) and preferred groups (β = 0.67; 95% CI: 0.26–1.08), whereas no significant difference was observed in the not preferred group. Similarly, increasing annual intake frequency was associated with higher blood mercury concentrations, with a significant association observed in those consuming shark meat 1–2 times per year (β = 0.40; 95% CI: 0.21–0.58), while the highest intake group showed borderline significance (β = 0.71; 95% CI: 0.00–1.43).
Due to the limited number of participants exceeding these predefined thresholds, we additionally defined elevated blood mercury levels based on the 75th percentile to ensure sufficient statistical power. Supplementary Table 1 summarizes the ORs for elevated blood mercury according to shark meat consumption habits. Compared with the non-consumption group, shark meat consumption had significantly higher odds of elevated mercury levels (adjusted OR: 2.69; 95% CI: 1.47–4.94). Participants who consumed shark meat within the past 30 days had the highest risk (adjusted OR: 8.46; 95% CI: 1.46–48.87), followed by those who consumed 31–60 days earlier (adjusted OR: 5.37; 95% CI: 1.83–15.75), while no significant increase was observed among those who had consumed more than 60 days prior (adjusted OR: 1.43; 95% CI: 0.62–3.29). Regarding preference, participants reporting a lower preference for shark meat had higher odds of elevated mercury (adjusted OR: 3.03; 95% CI: 1.50–6.12), whereas those who preferred shark meat showed a markedly increased risk, albeit with a wide confidence interval (adjusted OR: 6.80; 95% CI: 1.03–44.83). In terms of annual intake frequency, participants consuming shark meat 1–2 times per year exhibited significantly higher odds of high mercury levels (adjusted OR: 2.62; 95% CI: 1.39–4.93). Although the point estimate was highest for those consuming 3–6 times annually (adjusted OR: 3.71; 95% CI: 0.48–28.66), the association did not reach statistical significance due to the small sample size. Supplementary Fig. 1 presents a forest plot of the results shown in Supplementary Table 1, showing ORs and 95% CI for elevated blood mercury levels.
Table 4 presents the proportions of participants exceeding each blood mercury threshold. For concentrations ≥3.5 µg/L, 12.0% of consumers and 2.7% of non-consumers exceeded the threshold, yielding an OR of 6.35 (p < 0.001). For concentrations ≥5.0 µg/L, the respective proportions were 10.0% and 0.7%, with an OR of 16.96 (p < 0.001). For concentrations ≥5.8 µg/L, the proportions were 10.0% in the shark meat consumption group and 0.2% in the non-consumption group, corresponding to an OR of 35.84 (p < 0.001).
In Table 5, the estimated attributable risks of shark meat consumption for exceeding each threshold were 84.3% (95% CI: 50.0%–95.0%) for 3.5 µg/L, 94.1% (95% CI: 72.3%–98.7%) for 5.0 µg/L, and 97.2% (95% CI: 70.5%–99.7%) for 5.8 µg/L. The corresponding population attributable risks were 22.7% (95% CI: 5.2%–51.3%), 46.7% (95% CI: 12.6%–81.2%), and 65.7% (95% CI: 11.6–95.4%), respectively. Based on the average national population of adolescents aged 12–17 years in Korea from 2015 to 2017 (n = 3,217,506), the total estimated numbers of adolescents exceeding each threshold were 102,960 (3.5 µg/L), 38,610 (5.0 µg/L), and 25,740 (5.8 µg/L). The numbers of exceeders estimated to be attributable to shark meat consumption were approximately 23,372 (95% CI: 5,354–52,818), 18,031 (95% CI: 4,865–31,351), and 16,911 (95% CI: 2,986–24,556), respectively. These estimates should be interpreted cautiously given the wide confidence intervals.
DISCUSSION
In this study, we evaluated blood mercury concentrations among Korean adolescents and examined the association with shark meat consumption. The geometric mean blood mercury concentration was 1.38 µg/L, and levels were significantly higher in the shark meat consumption group compared with the non-consumption group. These findings suggest that shark meat intake is an important contributor to mercury exposure in Korean adolescents.
Compared with previous biomonitoring studies conducted in Germany, Sweden, Italy, the United States, and Canada, where mean blood mercury concentrations among adolescents ranged from 0.23 to 1.1 µg/L, the levels observed in the present study were relatively higher.18-22 Even adolescents who did not consume shark meat showed a mean blood mercury concentration of 1.36 µg/L, exceeding levels reported in most other countries. This finding indicates that overall mercury exposure among Korean adolescents is elevated, likely reflecting high fish consumption patterns. Korea’s geographical characteristics as a peninsula and the cultural dietary pattern with frequent seafood intake may contribute to this increased exposure.
Despite the relatively higher blood mercury concentrations, previous risk assessment studies have suggested that mercury exposure through seafood consumption in Korea remains within tolerable limits.23,24 The European Food Safety Authority has proposed provisional tolerable weekly intake (PTWI) values of 4.0 µg/kg body weight/week for total mercury and 1.3 µg/kg body weight/week for methylmercury.25 The estimated weekly intake of total mercury and methylmercury through seafood consumption was reported to be 0.463, 0.338 µg/kg body weight/week, corresponding to 11.6%, 26.0% of the PTWI.26 These findings indicate that, at the population level, seafood consumption may not pose a significant health risk. However, our results suggest that specific dietary behaviors, particularly the consumption of large predatory fish such as shark, may lead to substantially higher individual exposure levels, which could exceed recommended safety thresholds in certain subgroups.
Consistent with this, we observed a clear dose–response relationship between shark meat consumption patterns and blood mercury concentrations. More recent consumption, higher preference, and increased annual intake frequency were all associated with elevated mercury levels. Furthermore, the proportion of adolescents exceeding established blood mercury thresholds was markedly higher in the shark consumption group, indicating a substantial increase in risk associated with shark meat intake. These findings highlight the importance of considering not only overall seafood intake but also specific high-risk species in assessing mercury exposure.
Importantly, regional and cultural factors may further amplify mercury exposure in certain populations. Previous studies have reported that blood mercury levels among individuals in Gyeongsangbuk-do were significantly higher than those in other regions of Korea, and the use of shark meat in traditional ancestral rites (Jesa) was identified as a major source of exposure.14,27 In line with these findings, studies conducted among workers in Gyeongsangbuk-do reported geometric mean blood mercury concentrations of 4.11 µg/L overall, with significantly higher levels observed in the shark consumption group (4.58 µg/L) compared with the non-consumption group (3.68 µg/L). These levels are comparable to or slightly higher than those reported in national surveys, such as KNHANES in 2010 (2.22 µg/L).12 Collectively, these findings suggest that repeated and culturally driven consumption of shark meat, particularly through Jesa rituals, may contribute to sustained elevations in mercury exposure beyond general dietary intake.
Many countries have established detailed dietary guidelines to reduce mercury exposure from fish consumption, particularly for vulnerable populations. For example, the U.S. Environmental Protection Agency recommends avoiding high-mercury fish such as shark and swordfish among pregnant and breastfeeding women and provides differentiated guidance based on fish size.28 In Canada, intake guidelines for tuna, shark, and swordfish are stratified by general adults, pregnant or breastfeeding women, and children aged 1–4 and 5–11 years.29 Similarly, Japan’s Ministry of Health, Labour and Welfare recommends specific weekly limits for the consumption of whale, shark, and swordfish among pregnant and childbearing-age women.30 These international guidelines emphasize the importance of targeted risk communication and species-specific recommendations. In Korea, the Ministry of Food and Drug Safety has issued detailed guidelines for fish intake by categorizing populations into adults, pregnant or breastfeeding women, and children under 10 years old (1–2, 3–6, and 7–10 years), with intake recommendations specified for two types of fish groups: tuna/swordfish/shark and general fish/canned tuna.31 However, despite these efforts, there are currently no specific intake guidelines for adolescents. Given that adolescence is a critical developmental period and that our findings demonstrate relatively high mercury exposure in this population, the absence of tailored recommendations represents an important gap in current public health policy.
While our findings underscore the contribution of shark meat to mercury exposure, the nutritional benefits of fish consumption must also be considered when interpreting these results. Fish is the principal dietary source of long-chain omega-3 polyunsaturated fatty acids such as eicosapentaenoic acid and docosahexaenoic acid, which are essential for brain and visual development, and it also provides high-biological-value protein, fat-soluble vitamins, and trace elements.32 During pregnancy, regular maternal fish intake has been associated with improved offspring neurodevelopment despite concurrent methylmercury exposure, reflecting the net balance between nutrient benefits and contaminant risks.33,34 Adolescence is likewise a period of continued neurocognitive maturation; accordingly, the goal of mercury risk communication should not be to discourage fish consumption in general.34,35
Crucially, however, this risk–benefit balance is strongly species-dependent. Quantitative assessments comparing the methylmercury content and omega-3 fatty acid content of commonly consumed species have shown that the omega-3 benefits outweigh the mercury risks for low-mercury species such as farmed salmon, herring, and trout, whereas the opposite holds for high-mercury predatory species, most notably shark and swordfish, for which the net effect is unfavorable.36 As an apex predator, shark accumulates high concentrations of methylmercury through biomagnification, while offering no nutritional advantage that cannot be obtained from safer, lower-mercury species. From a risk–benefit perspective, therefore, the elevated mercury exposure associated with shark meat consumption observed in our study is unlikely to be offset by its nutritional value.
Taken together, our findings suggest that certain dietary patterns—particularly shark meat consumption— can significantly increase mercury exposure. Therefore, the development of age-specific and culturally informed dietary guidelines, including clear recommendations on shark meat intake, is warranted to reduce potential health risks among Korean adolescents.
CONCLUSIONS
This study identified an association between shark meat consumption and blood mercury levels, as shark—a large predatory fish at the top of the food chain—contains a high accumulation of mercury. To prevent unintentional exposure among children and adolescents, education on the potential health risks associated with mercury exposure from shark meat should be provided in schools. However, such education should be carefully designed to avoid causing excessive concern or overlooking the nutritional benefits of fish and shellfish consumption.
Abbreviations
ANOVA
analysis of variance
aOR
adjusted odds ratios
CI
confidence interval
HBM
Human Biomonitoring
KoNEHS
Korean National Environmental Health Survey
KNHANES
Korea National Health and Nutrition Examination Survey
OR
odds ratio
PTWI
provisional tolerable weekly intake
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Funding
This research was supported by the Environmental Health Center for Training Environmental Medicine Professionals at Inha University Hospital, funded by the Ministry of Environment, Republic of Korea.
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Competing interests
The authors declare that they have no competing interests.
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Author contributions
Conceptualization: Park JW. Data curation: Chang JA. Formal analysis: Chang JA, Park JW. Funding acquisition: Park JW. Investigation: Chang JA, Park JW. Methodology: Park JW. Project administration: Park JW. Supervision: Park JW. Validation: SaKong J. Visualization: Chang JA, SaKong J. Writing - original draft: Chang JA, Park JW. Writing - review & editing: SaKong J.
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Acknowledgments
This study was used the Korean National Environmental Health Survey (KoNEHS) Cycle 3 (2015-2017) data, made by National Institute of Environmental Research (NIER-2017-01-01-001).
NOTES
SUPPLEMENTARY MATERIAL
Supplementary Table 1.
The ORs (95% CI) for elevated blood mercury level (≥75th percentile), according to shark meat consumption habits (frequency, timing, and preference of shark meat), estimated by logistic regression analysis.
Supplementary Fig. 1.
Forest plot of odds ratios for elevated blood mercury levels according to shark meat consumption habits.
Table 1.
Distribution of shark meat consumption according to participants’ characteristics
Table 2.
Geometric mean blood mercury concentration according to shark meat consumption and participants’ characteristics
Table 3.
Geometric blood mercury concentrations according to shark meat consumption habits (time since last consumption, preference and annual intake) and their association with log-transformed blood mercury concentrations
Table 4.
Prevalence and odds of exceeding blood mercury reference levels according to shark meat consumption using logistic regression analysis
| Reference level (µg/L) | No. (%) | aOR (95% CI) | p-value | |
|---|---|---|---|---|
| Consumption (n = 50) | Non-consumption (n = 862) | |||
| ≥3.5a | 6 (12.0) | 23 (2.7) | 6.35 (2.00–20.11) | <0.001 |
| ≥5.0b | 5 (10.0) | 6 (0.7) | 16.96 (3.61–79.62) | <0.001 |
| ≥5.8c | 5 (10.0) | 2 (0.2) | 35.84 (3.39–378.84) | <0.001 |
| ≥15.0d | 0 (0) | 0 (0) | NE | – |
Values are the number (%) of participants whose blood mercury concentration met or exceeded each reference level.
Adjusted odds ratios (aOR) were obtained from multivariable logistic regression with the shark-meat non-consumption group as reference, adjusted for sex, age, smoking, obesity, and consumption of large predatory fish, small pelagic fish, seaweed, crab, and shellfish. Estimates based on small cell counts should be interpreted with caution.
CI: confidence interval; NE: not estimable (no participant exceeded this level).
a3.5 µg/L: recommended maternal blood mercury level, estimated on the assumption that cord blood mercury is approximately 1.7 times higher than maternal blood16,17;
b5.0 µg/L: Human Biomonitoring (HBM) I value proposed by the German Federal Environmental Agency, below which no adverse health effects are expected15;
c5.8 µg/L: derived from the cord blood mercury concentration corresponding to the U.S. Environmental Protection Agency reference dose of 0.1 µg/kg body weight/day16;
d15.0 µg/L: HBM II value proposed by the German Federal Environmental Agency, above which adverse health effects are possible and immediate exposure reduction is recommended15.
Table 5.
ORs and attributable risks for elevated blood mercury levels at different thresholds according to shark meat consumption
| Consumption rate (%) | Blood mercurya (µg/L) | aORb (95% CI) | Attributable risk (%)c (95% CI) | Attributable risk for the total population (%)d (95% CI) | Proportion of reference level exceeder (%) (95% CI) | Total reference level exceeder (n)e (95% range) | Exceeders attributable to shark meat consumption (n)f (95% CI) |
|---|---|---|---|---|---|---|---|
| 5.5 | 3.5 | 6.35 (2.00–20.11) | 84.3 (50.0–95.0) | 22.7 (5.2–51.3) | 3.2 (2.2–4.6) | 102,960 (71,430–147,683) | 23,372 (5,354–52,818) |
| 5.0 | 16.96 (3.61–79.62) | 94.1 (72.3–98.7) | 46.7 (12.6–81.2) | 1.2 (0.7–2.1) | 38,610 (21,235–66,923) | 18,031 (4,865–31,351) | |
| 5.8 | 35.84 (3.39–378.84) | 97.2 (70.5–99.7) | 65.7 (11.6–95.4) | 0.8 (0.4–1.7) | 25,740 (11,905–54,913) | 16,911 (2,986–24,556) |
aOR: adjusted odds ratio; CI: confidence interval; OR: odds ratio.
aBlood mercury concentration applied as the reference level for defining exceedance at each threshold;
bValues were adjusted for sex, age, smoking, obesity, consumption of large predatory fish, small pelagic fish, seaweed, crab, and shellfish;
cAttributable risk (%) = [(OR – 1)/OR] × 100;
dAttributable risk for the total population (%) = [Consumption rate(OR – 1)/(Consumption rate(OR – 1) + 1)] × 100;
eReference level exceeder (n) = Proportion of reference level exceeder × average number of aged 12–17 in South Korea from 2015 to 2017 (3,217,506). The 95% range was derived by applying the 95% CI of the weighted proportion to this reference population;
fExceeders attributable to shark meat consumption (n) = Total reference level exceeders (N) × population attributable risk for total population (%)/100.
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XML DownloadRelationship between shark meat intake and blood mercury concentration in Korean adolescents
Relationship between shark meat intake and blood mercury concentration in Korean adolescents
| Characteristic | No. (%) | Shark meat consumption | p-value | |
|---|---|---|---|---|
| Consumption | Non-consumption | |||
| Sex | 0.678 | |||
| Male | 430 (47.1) | 25 (5.8) | 405 (94.2) | |
| Female | 482 (52.9) | 25 (5.2) | 457 (94.8) | |
| Age (years) | 0.017 | |||
| 12–14 | 460 (50.4) | 17 (3.7) | 443 (96.3) | |
| 15–17 | 452 (49.6) | 33 (7.3) | 419 (92.7) | |
| Smoking | 0.704 | |||
| Never-smoker | 865 (94.8) | 48 (5.5) | 817 (94.5) | |
| Ever smoker | 47 (5.2) | 2 (4.3) | 45 (95.7) | |
| Obesity | 0.887 | |||
| Without obesity | 778 (85.3) | 43 (5.5) | 735 (94.5) | |
| With obesity | 134 (14.7) | 7 (5.2) | 127 (94.8) | |
| Large predatory fish consumption | 0.004 | |||
| Rarely | 518 (56.8) | 17 (3.3) | 501 (96.7) | |
| ≥1/month | 271 (29.7) | 23 (8.5) | 248 (91.5) | |
| ≥1/week | 123 (13.5) | 10 (8.1) | 113 (91.9) | |
| Small pelagic fish consumption | 0.227 | |||
| Rarely | 159 (17.4) | 11 (6.9) | 148 (93.1) | |
| ≥1/month | 453 (49.7) | 28 (6.2) | 425 (93.8) | |
| ≥1/week | 300 (32.9) | 11 (3.7) | 289 (96.3) | |
| Crab consumption | 0.094 | |||
| Rarely | 410 (45.0) | 18 (4.4) | 392 (95.6) | |
| ≥1/month | 419 (45.9) | 30 (7.2) | 389 (92.8) | |
| ≥1/week | 83 (9.1) | 2 (2.4) | 81 (97.6) | |
| Seaweed consumption | 0.177 | |||
| Rarely | 110 (12.1) | 5 (4.5) | 105 (95.5) | |
| ≥1/month | 343 (37.6) | 25 (7.3) | 318 (92.7) | |
| ≥1/week | 459 (50.3) | 20 (4.4) | 439 (95.6) | |
| Shellfish consumption | 0.769 | |||
| Rarely | 468 (51.3) | 26 (5.6) | 442 (94.4) | |
| ≥1/month | 364 (39.9) | 21 (5.8) | 343 (94.2) | |
| ≥1/week | 80 (8.8) | 3 (3.8) | 77 (96.3) | |
| Total | 912 (100) | 50 (5.5) | 862 (94.5) | |
| Characteristic | Blood mercury concentration (95% CI) (µg/L) | |||||
|---|---|---|---|---|---|---|
| Consumption | p-value | Non-consumption | p-value | Total | p-value | |
| Sex | 0.018 | 0.032 | 0.006 | |||
| Male | 2.37 (1.83–3.06) | 1.41 (1.35–1.47) | 1.45 (1.39–1.52) | |||
| Female | 1.61 (1.31–1.96) | 1.31 (1.25–1.37) | 1.33 (1.27–1.39) | |||
| Age (years) | 0.971 | 0.509 | 0.811 | |||
| 12–14 | 1.96 (1.39–2.77) | 1.37 (1.31–1.44) | 1.39 (1.33–1.45) | |||
| 15–17 | 1.95 (1.60–2.36) | 1.34 (1.28–1.40) | 1.38 (1.32–1.44) | |||
| Smoking | 0.943 | 0.102 | 0.139 | |||
| Never smoker | 1.95 (1.64–2.32) | 1.35 (1.30–1.39) | 1.38 (1.33–1.42) | |||
| Ever smoker | 1.89 (0.05–76.52) | 1.52 (1.29–1.79) | 1.54 (1.31–1.80) | |||
| Obesity | 0.387 | 0.017 | 0.043 | |||
| Without obesity | 2.01 (1.66–2.43) | 1.33 (1.29–1.38) | 1.36 (1.32–1.41) | |||
| With obesity | 1.63 (1.38–1.92) | 1.49 (1.37–1.63) | 1.50 (1.38–1.63) | |||
| Large predatory fish consumption | 0.901 | 0.023 | 0.007 | |||
| Rarely | 1.88 (1.40–2.51) | 1.31 (1.26–1.37) | 1.33 (1.27–1.38) | |||
| ≥1/month | 2.03 (1.58–2.61) | 1.39 (1.31–1.48) | 1.44 (1.36–1.53) | |||
| ≥1/week | 1.89 (1.29–2.77) | 1.49 (1.36–1.63) | 1.52 (1.39–1.66) | |||
| Small pelagic fish consumption | 0.672 | <0.001 | <0.001 | |||
| Rarely | 1.90 (1.32–2.72) | 1.15 (1.07–1.25) | 1.19 (1.10–1.29) | |||
| ≥1/month | 2.07 (1.65–2.60) | 1.36 (1.30–1.42) | 1.39 (1.33–1.46) | |||
| ≥1/week | 1.72 (1.20–2.47) | 1.47 (1.39–1.56) | 1.48 (1.40–1.57) | |||
| Crab consumption | 0.624 | 0.003 | 0.002 | |||
| Rarely | 1.80 (1.36–2.38) | 1.28 (1.22–1.34) | 1.30 (1.24–1.36) | |||
| ≥1/month | 2.08 (1.67–2.58) | 1.40 (1.34–1.47) | 1.44 (1.38–1.51) | |||
| ≥1/week | 1.57 (0.67–3.64) | 1.51 (1.36–1.68) | 1.51 (1.36–1.69) | |||
| Seaweed consumption | 0.387 | 0.167 | 0.050 | |||
| Rarely | 1.47 (0.87–2.49) | 1.29 (1.17–1.41) | 1.30 (1.18–1.42) | |||
| ≥1/month | 2.14 (1.69–2.71) | 1.41 (1.34–1.49) | 1.45 (1.38–1.53) | |||
| ≥1/week | 1.86 (1.43–2.42) | 1.34 (1.28–1.40) | 1.36 (1.29–1.42) | |||
| Shellfish consumption | 0.376 | <0.001 | <0.001 | |||
| Rarely | 1.75 (1.39–2.20) | 1.27 (1.21–1.33) | 1.29 (1.24–1.35) | |||
| ≥1/month | 2.16 (1.67–2.80) | 1.45 (1.38–1.53) | 1.49 (1.41–1.57) | |||
| ≥1/week | 2.44 (1.24–4.83) | 1.45 (1.30–1.61) | 1.48 (1.33–1.65) | |||
| Total | 1.95 (1.65–2.30) | 1.36 (1.31–1.40) | 1.38 (1.34–1.43) | |||
| No. (%) | Blood mercury level (µg/L) | Crude | Adjusted | |||
|---|---|---|---|---|---|---|
| Estimate (95% CI) | p-value | Estimate (95% CI) | p-value | |||
| All subjects | ||||||
| Non-consumption | 862 (94.5) | 1.36 | Ref | Ref | ||
| Consumption | 50 (5.5) | 1.95 | 0.41 (0.23 to 0.59) | <0.001 | 0.41 (0.23 to 0.59) | <0.001 |
| Time since last consumption | ||||||
| Non-consumption | 862 (94.5) | 1.36 | Ref | Ref | ||
| >60 days | 29 (3.2) | 1.67 | 0.28 (0.10 to 0.45) | 0.002 | 0.27 (0.09 to 0.44) | 0.003 |
| 31–60 days | 15 (1.6) | 2.16 | 0.53 (0.24 to 0.81) | <0.001 | 0.52 (0.24 to 0.80) | <0.001 |
| ≤30 days | 6 (0.7) | 3.17 | 1.13 (0.24 to 2.01) | 0.013 | 1.19 (0.30 to 2.08) | 0.009 |
| Shark meat preference | ||||||
| Non-consumption | 862 (94.5) | 1.36 | Ref | Ref | ||
| Not preferred | 9 (1.0) | 1.42 | 0.16 (–0.01 to 0.34) | 0.068 | 0.14 (–0.06 to 0.35) | 0.173 |
| Less preferred | 36 (4.0) | 2.03 | 0.48 (0.24 to 0.71) | <0.001 | 0.47 (0.24 to 0.71) | <0.001 |
| Preferred | 5 (0.6) | 2.56 | 0.58 (0.17 to 1.00) | 0.006 | 0.67 (0.26 to 1.08) | 0.001 |
| Annual intake (times per year) | ||||||
| Non-consumption | 862 (94.5) | 1.36 | Ref | Ref | ||
| 1–2 | 46 (5.0) | 1.85 | 0.40 (0.22 to 0.58) | <0.001 | 0.40 (0.21 to 0.58) | <0.001 |
| 3–6 | 4 (0.4) | 3.49 | 0.72 (–0.06 to 1.50) | 0.070 | 0.71 (0.00 to 1.43) | 0.050 |
| Reference level (µg/L) | No. (%) | aOR (95% CI) | p-value | |
|---|---|---|---|---|
| Consumption (n = 50) | Non-consumption (n = 862) | |||
| ≥3.5 |
6 (12.0) | 23 (2.7) | 6.35 (2.00–20.11) | <0.001 |
| ≥5.0 |
5 (10.0) | 6 (0.7) | 16.96 (3.61–79.62) | <0.001 |
| ≥5.8 |
5 (10.0) | 2 (0.2) | 35.84 (3.39–378.84) | <0.001 |
| ≥15.0 |
0 (0) | 0 (0) | NE | – |
| Consumption rate (%) | Blood mercury |
aOR |
Attributable risk (%) |
Attributable risk for the total population (%) |
Proportion of reference level exceeder (%) (95% CI) | Total reference level exceeder (n) |
Exceeders attributable to shark meat consumption (n) |
|---|---|---|---|---|---|---|---|
| 5.5 | 3.5 | 6.35 (2.00–20.11) | 84.3 (50.0–95.0) | 22.7 (5.2–51.3) | 3.2 (2.2–4.6) | 102,960 (71,430–147,683) | 23,372 (5,354–52,818) |
| 5.0 | 16.96 (3.61–79.62) | 94.1 (72.3–98.7) | 46.7 (12.6–81.2) | 1.2 (0.7–2.1) | 38,610 (21,235–66,923) | 18,031 (4,865–31,351) | |
| 5.8 | 35.84 (3.39–378.84) | 97.2 (70.5–99.7) | 65.7 (11.6–95.4) | 0.8 (0.4–1.7) | 25,740 (11,905–54,913) | 16,911 (2,986–24,556) |
Table 1. Distribution of shark meat consumption according to participants’ characteristics
Values are presented as number (%).
Table 2. Geometric mean blood mercury concentration according to shark meat consumption and participants’ characteristics
CI: confidence interval.
Table 3. Geometric blood mercury concentrations according to shark meat consumption habits (time since last consumption, preference and annual intake) and their association with log-transformed blood mercury concentrations
Estimates represent β coefficients for log-transformed blood mercury concentrations. Adjusted for sex, age, smoking, obesity, consumption of large predatory fish, small pelagic fish, seaweed, crab, and shellfish. CI: confidence interval.
Table 4. Prevalence and odds of exceeding blood mercury reference levels according to shark meat consumption using logistic regression analysis
Values are the number (%) of participants whose blood mercury concentration met or exceeded each reference level. Adjusted odds ratios (aOR) were obtained from multivariable logistic regression with the shark-meat non-consumption group as reference, adjusted for sex, age, smoking, obesity, and consumption of large predatory fish, small pelagic fish, seaweed, crab, and shellfish. Estimates based on small cell counts should be interpreted with caution. CI: confidence interval; NE: not estimable (no participant exceeded this level). 3.5 µg/L: recommended maternal blood mercury level, estimated on the assumption that cord blood mercury is approximately 1.7 times higher than maternal blood 5.0 µg/L: Human Biomonitoring (HBM) I value proposed by the German Federal Environmental Agency, below which no adverse health effects are expected 5.8 µg/L: derived from the cord blood mercury concentration corresponding to the U.S. Environmental Protection Agency reference dose of 0.1 µg/kg body weight/day 15.0 µg/L: HBM II value proposed by the German Federal Environmental Agency, above which adverse health effects are possible and immediate exposure reduction is recommended
Table 5. ORs and attributable risks for elevated blood mercury levels at different thresholds according to shark meat consumption
aOR: adjusted odds ratio; CI: confidence interval; OR: odds ratio. Blood mercury concentration applied as the reference level for defining exceedance at each threshold; Values were adjusted for sex, age, smoking, obesity, consumption of large predatory fish, small pelagic fish, seaweed, crab, and shellfish; Attributable risk (%) = [(OR – 1)/OR] × 100; Attributable risk for the total population (%) = [Consumption rate(OR – 1)/(Consumption rate(OR – 1) + 1)] × 100; Reference level exceeder (n) = Proportion of reference level exceeder × average number of aged 12–17 in South Korea from 2015 to 2017 (3,217,506). The 95% range was derived by applying the 95% CI of the weighted proportion to this reference population; Exceeders attributable to shark meat consumption (n) = Total reference level exceeders (N) × population attributable risk for total population (%)/100.
