Food
Draft Report of Quantitative Risk and Benefit Assessment of Consumption of Commercial Fish, Focusing on Fetal Neurodevelopmental Effects (Measured by Verbal Development in Children) and on Coronary Heart Disease and Stroke in the General Population: Appendix B, Modeling Results
January 15, 2009
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Return to Draft Risk and Benefit Report Tabe of Contents
(a) Baseline Estimates
The estimates generated by the model for the U.S. population are presented in this section. Results are presented for each of four population groups, Younger Women aged 15-45, Younger Men aged 15-45, Older Women aged 46 and older, and Older Men aged 46 and older. The results for the first group, which includes women of childbearing age, also address neurobehavioral effects on children resulting from maternal exposure.
Fish Consumption
The distributions for fish consumption of each subpopulation are presented in Table AB-1.
Population Percentile | Women 15-45 | Women 46+ | Men 15-45 | Men 46+ |
---|---|---|---|---|
Average | 13.1 (12.4, 13.8) | 14.9 (14.3, 15.7) | 17.9 (16.8, 19.0) | 18.8 (17.7, 20.0) |
10th Percentile | 0.1 (0.0, 0.9) | 0.2 (0.0, 1.3) | 0.2 (0.0, 1.3) | 0.2 (0.0, 1.7) |
25th Percentile | 2.8 (2.0, 3.4) | 3.4 (2.5, 4.3) | 3.7 (2.5, 4.6) | 4.5 (3.1, 5.6) |
Median | 7.0 (6.1, 7.7) | 8.2 (7.2, 8.9) | 9.3 (8.1, 10.4) | 10.7 (9.1, 11.6) |
75th Percentile | 16.0 (14.8, 17.3) | 18.0 (16.8, 19.2) | 21.3 (19.1, 23.1) | 22.3 (20.4, 24.1) |
90th Percentile | 31.3 (29.2, 33.9) | 36.3 (33.3, 38.7) | 42.9 (39.2, 47.5) | 43.9 (39.8, 49.0) |
95th Percentile | 45.4 (41.2, 51.3) | 53.3 (47.7, 59.8) | 63.9 (58.4, 73.2) | 64.8 (57.4, 77.5) |
99th Percentile | 88.0 (73.6, 112.9) | 100.0 (84.9, 126.6) | 132.4 (109.7, 170.3) | 127.4 (100.8, 167.7) |
NHANES Average | 10.3 | 14.2 | 16.8 | 20.8 |
Because our model is based in part on data from 1989-1991, the table includes average daily consumption taken from the 2003-2004 NHANES survey in order to verify that our results are consistent with current consumption patterns. The reference for this is the Documentation, Codebook, and Frequencies, Dietary Interview - Individual Foods (First Day), for the National Health and Nutrition Examination Survey for 2003-2004 (USDA/HHS 2007). This document is primarily involved with survey methodology. The data we used are in a file referenced in the document, i.e., SAS Transport File DR1IFF_C and DR2IFF_C.XTP.
Blood and Hair Mercury Levels
The distributions for blood and hair mercury levels in younger women are presented in Table AB-2. For purposes of comparison, the model estimates are compared to results from NHANES in Figures AB-1 and AB-2. It may be observed that the blood levels model are generally 20-25 percent lower than the levels observed in NHANES, while the hair levels are 30-40 percent lower. These discrepancies may be explained, at least in part, by two factors:
- While the NHANES measurements are for total mercury in both blood and hair, the model is intended to estimate concentrations on just methylmercury.
- The model has been updated with more recent (2005) market data indicating that the consumption patterns have changed somewhat so that the average commercial fish weighted by frequency of consumption, now has less methylmercury in it than when the most recently reported NHANES mercury biomarker survey data were conducted (2000 for hair and 2002 for blood).
Population Percentile | Dietary Hg from Fish (µg/day) | Blood Hg (µg/L): | Hair Hg (ppm) |
---|---|---|---|
Average | 1.4 (1.3, 1.4) | 1.2 (1.2, 1.3) | 0.3 (0.2, 0.3) |
10th Percentile | 0.0 (0.0, 0.1) | 0.1 (0.1, 0.1) | 0.0 (0.0, 0.0) |
25th Percentile | 0.2 (0.1, 0.3) | 0.3 (0.2, 0.3) | 0.0 (0.0, 0.1) |
Median | 0.7 (0.6, 0.7) | 0.6 (0.5, 0.7) | 0.1 (0.1, 0.1) |
75th Percentile | 1.6 (1.5, 1.8) | 1.5 (1.3, 1.6) | 0.3 (0.2, 0.3) |
90th Percentile | 3.4 (3.1, 3.6) | 2.9 (2.7, 3.2) | 0.6 (0.5, 0.7) |
95th Percentile | 4.9 (4.5, 5.5) | 4.3 (3.8, 4.8) | 1.0 (0.8, 1.2) |
99th Percentile | 10.3 (8.1, 12.8) | 8.8 (7.4, 10.7) | 2.2 (1.8, 2.7) |
Population Percentile | Dietary Hg from Fish (µg/day) | Blood Hg (µg/L) | Hair Hg (ppm) |
---|---|---|---|
Average | 1.8 (1.7, 1.9) | 1.4 (1.3, 1.5) | 0.3 (0.3, 0.4) |
10th Percentile | 0.0 (0.0, 0.1) | 0.1 (0.1, 0.1) | 0.0 (0.0, 0.0) |
25th Percentile | 0.3 (0.2, 0.4) | 0.3 (0.2, 0.4) | 0.1 (0.0, 0.1) |
Median | 0.9 (0.7, 1.0) | 0.7 (0.6, 0.8) | 0.1 (0.1, 0.2) |
75th Percentile | 2.1 (1.9, 2.3) | 1.7 (1.5, 1.9) | 0.3 (0.3, 0.4) |
90th Percentile | 4.3 (3.9, 4.7) | 3.3 (3.0, 3.7) | 0.7 (0.6, 0.8) |
95th Percentile | 6.4 (5.6, 7.5) | 5.0 (4.4, 5.7) | 1.1 (0.9, 1.3) |
99th Percentile | 13.4 (10.9, 17.3) | 10.4 (8.5, 12.8) | 2.4 (2.0, 3.2) |
Figure AB-1: Quantile-Quantile Comparison of Model Estimates of Blood Mercury with Values from NHANES
NHANES survey data are taken from the 199-200, 2001-2002, and 2003-2004 surveys (CDC 2004). The following percentiles are plotted: 10^{th}, 25^{th}, 50^{th}, 75^{th}, 90^{th}, 95^{th}, 99^{th}. 99.5^{th}, and 99.9^{th}. Percentiles were calculated with the demographic weights provided with the survey data.
Figure AB-2: Quantile-Quantile Comparison of Model Estimates of Hair Mercury with Values from NHANES
NHANES survey data are taken from CDC (2001), which reflects data collected from 1999-2000. The following percentiles are plotted: 10^{th}, 25^{th}, 50^{th}, 75^{th}, 90^{th}, and 95^{th}.
Neurobehavioral Effects Attributable to Methylmercury Exposure
The predicted neurobehavioral effects resulting from current levels of methylmercury on verbal performance in toddlers with and without taking into account potential offsetting effects from fish consumption are presented in Table AB-4. Since the endpoints or responses modeled are not identical, the results are all represented as a Z-score where the outcome is expressed relative to normal variation (i.e. each Z unit = one standard deviation). The Carrington and Bolger (2000) model for delayed talking was normalized using the standard deviation from Seychelles of 2.76 months. In order to investigate the possible consequences of beneficial effects of maternal consumption of fish, a simulation model was constructed that included both methylmercury effects characterized with the Carrington and Bolger (2000) delayed talking analysis, and an uncertain range of beneficial effects based on the verbal comprehension regression analyses from the Daniels et al. (2004) study. This analysis presumes that the contribution of fish to the slope for delayed talking (which was dominated by the data from Iraq, where methylmercury was ingested in bread) and the contribution of mercury to the apparent benefit observed in the Daniels study are both negligible.
Population Percentile | Carrington (2000), Age of Talking | Net Verbal ΔZ |
---|---|---|
Average | -2.9E-3 (-4.5E-3, -6.1E-4) | 0.008 (0.000, 0.012) |
1st Percentile | -2.7E-2 (-4.2E-2, -8.5E-3) | -0.001 (-0.020, 0.000) |
5th Percentile | -1.2E-2 (-1.8E-2, -3.3E-3) | 0.000 (-0.006, 0.001) |
10th Percentile | -7.3E-3 (-1.1E-2, -1.7E-3) | 0.001 (-0.003, 0.002) |
25th Percentile | -3.2E-3 (-4.8E-3, 2.2E-4) | 0.002 (0.000, 0.004) |
Median | -1.1E-3 (-1.8E-3, 0.0E0) | 0.005 (0.000, 0.008) |
75th Percentile | -2.9E-4 (-5.2E-4, 0.0E0) | 0.010 (0.001, 0.016) |
90th Percentile | 0.0E0 (-6.8E-5, 0.0E0) | 0.020 (0.003, 0.030) |
95th Percentile | 0.0E0 (6.8E0, 0.0E0) | 0.026 (0.005, 0.039) |
99th Percentile | 0.0E0 (0.0E0, 0.0E0) | 0.035 (0.010, 0.048) |
For comparison, predicted neurobehavioral effects for several other dose-response functions are presented in Table AB-5. Since IQ is defined as the Z score x 15, the Axelrad et al. (2007) and Cohen et al. (2005b) models were converted by dividing by 15. The Carrington (2000) model for delayed walking was normalized using the standard deviation from Seychelles of 1.96 months.
Population Percentile | Carrington (2000), Age of Walking | Cohen et al. (2005b) IQ | Axelrad et al. (2007) IQ |
---|---|---|---|
Average | -6.0E-3 (-9.3E-3, | -1.8E-3 (-1.3E-2, 1.3E-3) | -3.0E-3 (-5.6E-3, -7.0E-4) |
1st Percentile | -6.0E-2 (-1.0E-1, 0.0E0) | -1.6E-2 (-1.2E-1, 0.0E0) | -2.6E-2 (-5.0E-2, -6.1E-3) |
5th Percentile | -2.4E-2 (-3.7E-2, 0.0E0) | -7.1E-3 (-5.2E-2, 0.0E0) | -1.2E-2 (-2.2E-2, -2.8E-3) |
10th Percentile | -1.4E-2 (-2.3E-2, 0.0E0) | -4.5E-3 (-3.2E-2, 7.4E-6) | -7.5E-3 (-1.4E-2, -1.6E-3) |
25th Percentile | -5.8E-3 (-1.0E-2, 0.0E0) | -2.0E-3 (-1.5E-2, 1.5E-4) | -3.4E-3 (-6.4E-3, -7.5E-4) |
Median | -1.8E-3 (-3.5E-3, 0.0E0) | -7.4E-4 (-5.6E-3, 5.5E-4) | -1.3E-3 (-2.4E-3, -2.7E-4) |
75th Percentile | -3.7E-4 (-9.3E-4, 0.0E0) | -2.1E-4 (-1.7E-3, 1.4E-3) | -3.6E-4 (-7.6E-4, -7.8E-5) |
90th Percentile | 0.0E0 (-1.2E-4, 0.0E0) | 0.0E0 (-1.9E-4, 3.1E-3) | -4.1E-6 (-1.0E-4, 0.0E0) |
Cardiovascular Effects Attributable to Fish Consumption
Table AB-6 and Table AB-7 give the estimated annual reduction in the rate of occurrence of CHD Death and Stroke Death attributable to current levels of fish consumption.
Population Group | CHD Death Cases Per Person-Year Pooled Analysis Model | CHD Death Cases Per Person-Year Meta-Analysis Model |
---|---|---|
Women 15-45 | -1.1E-6 (-2.2E-5, 2.6E-6) | -6.8E-7 (-1.3E-6, -1.3E-7) |
Women 46+ | -2.8E-4 (-4.2E-3, 9.2E-4) | -2.2E-4 (-4.3E-4, -4.0E-5) |
Men 15-45 | -1.1E-5 (-1.2E-4, 3.4E-5) | -8.9E-6 (-1.7E-5, -1.6E-6) |
Men 46+ | -4.7E-4 (-8.8E-3, 6.5E-4) | -3.7E-4 (-7.2E-4, -6.6E-5) |
Population Group | Stroke Death Cases Per Person-Year Pooled Analysis Model | Stroke Death Cases Per Person-Year Meta-Analysis Model |
---|---|---|
Women 15-45 | -3.7E-6 (-3.1E-5, 1.5E-6) | -3.0E-6 (-5.6E-6, -9.1E-7) |
Women 46+ | -2.2E-4 (-2.7E-3, 1.4E-4) | -2.2E-4 (-4.1E-4, -7.1E-5) |
Men 15-45 | -4.0E-6 (-3.1E-5, 3.1E-6) | -3.2E-6 (-6.1E-6, -1.1E-6) |
Men 46+ | -2.4E-4 (-2.0E-3, 9.2E-5) | -1.8E-4 (-3.4E-4, -6.6E-5) |
(b) Intervention Scenarios
Advisory Scenario: 12 oz Limits for Women of Childbearing Age
To examine the impact of fish consumption advisories, several scenarios were developed. The first scenario introduced a 12 oz. per week consumption limit for all women of childbearing age. This modification of the exposure model involved truncating consumption of fish at the specified limit. Whereas individuals coming more that 12 oz. /week are reduced to 12 oz., those individuals who are already consuming under that limit do not modify their consumption. The impact of the advisory on neurobehavioral outcome occurring as a result of the reduction in exposure to methylmercury, expressed as a Z-score, is presented in Table AB-8.
Population Percentile | Carrington (2000), Age of Talking | Axelrad (2007) IQ | Net Verbal ΔZ |
---|---|---|---|
Average | 2.6E-4 (3.7E-5, 4.5E-4) | 2.2E-4 (4.6E-4, 7.1E-5) | -7.3E-4 (-1.5E-3, -2.8E-5) |
1st Percentile | 0.0E0 (0.0E0, 0.0E0) | 0.0E0 (0.0E0, 0.0E0) | -1.3E-1 (-3.0E-1, -3.0E-2) |
5th Percentile | 0.0E0 (0.0E0, 0.0E0) | 0.0E0 (0.0E0, 0.0E0) | -2.1E-2 (-4.6E-2, -2.7E-3) |
10th Percentile | 0.0E0 (0.0E0, 0.0E0) | 0.0E0 (0.0E0, 0.0E0) | 0.0E0 (-1.3E-3, 0.0E0) |
25th Percentile | 0.0E0 (0.0E0, 0.0E0) | 0.0E0 (0.0E0, 0.0E0) | 0.0E0 (0.0E0, 0.0E0) |
Median | 0.0E0 (0.0E0, 0.0E0) | 0.0E0 (0.0E0, 0.0E0) | 0.0E0 (0.0E0, 0.0E0) |
75th Percentile | 0.0E0 (0.0E0, 0.0E0) | 0.0E0 (0.0E0, 0.0E0) | 0.0E0 (0.0E0, 0.0E0) |
90th Percentile | 0.0E0 (0.0E0, 0.0E0) | 0.0E0 (0.0E0, 0.0E0) | 0.0E0 (0.0E0, 0.0E0) |
95th Percentile | 0.0E0 (0.0E0, 3.2E-4) | 0.0E0 (2.6E-4, 0.0E0) | 0.0E0 (0.0E0, 0.0E0) |
99th Percentile | 7.8E-3 (1.8E-4, 1.3E-2) | 6.8E-3 (1.3E-2, 1.9E-3) | 0.0E0 (0.0E0, 0.0E0) |
A second scenario used a 12 oz limit in conjunction with a stipulation that only fish species with average concentrations below 12 ppb are consumed by all women of childbearing age. This modification of the exposure model involved substituting fish species below the concentration limit for species above the limit. The impact of the advisory, relative to current levels of consumption, is presented in Table AB-9.
Population Percentile | Carrington (2000), Age of Talking | Axelrad (2007) IQ | Net Verbal ΔZ |
---|---|---|---|
Average | 1.3E-3 (1.6E-4, 1.9E-3) | 1.2E-3 (4.3E-4, 2.0E-3) | 5.2E-4 (-8.7E-4, 1.4E-3) |
1st Percentile | 0.0E0 (0.0E0, 0.0E0) | -4.1E-5 (-2.4E-4, -6.4E-6) | -3.4E-2 (-6.8E-2, -9.3E-3) |
5th Percentile | 0.0E0 (0.0E0, 0.0E0) | 0.0E0 (0.0E0, 0.0E0) | -1.3E-2 (-2.3E-2, -3.1E-3) |
10th Percentile | 0.0E0 (0.0E0, 0.0E0) | 0.0E0 (0.0E0, 0.0E0) | -6.5E-3 (-1.2E-2, - 1.5E-3) |
25th Percentile | 2.5E-5 (0.0E0, 7.1E-5) | 2.9E-5 (2.3E-6, 8.4E-5) | -1.5E-3 (-3.2E-3, -1.3E-4) |
Median | 3.1E-4 (0.0E0, 4.6E-4) | 3.1E-4 (1.0E-4, 5.5E-4) | 3.7E-5 (0.0E0, 4.9E-4) |
75th Percentile | 1.1E-3 (0.0E0, 1.6E-3) | 1.0E-3 (3.5E-4, 1.8E-3) | 2.9E-3 (1.3E-3, 4.9E-3) |
90th Percentile | 3.0E-3 (7.5E-5, 4.3E-3) | 2.6E-3 (9.3E-4, 4.5E-3) | 9.2E-3 (4.1E-3, 1.5E-2) |
95th Percentile | 5.3E-3 (3.8E-4, 7.8E-3) | 4.6E-3 (1.7E-3, 7.7E-3) | 1.6E-2 (7.0E-3, 2.3E-2) |
99th Percentile | 1.7E-2 (3.0E-3, 2.5E-2) | 1.4E-2 (5.1E-3, 2.5E-2) | 2.8E-2 (1.6E-2, 4.2E-2) |
The change in cardiovascular risk for both these scenarios (fish consumption is identical) are presented in Tables AB-10 and AB-11.
Population Group | CHD Death Cases Per Person-Year Pooled Analysis Model | CHD Death Cases Per Person-Year Meta-Analysis Model |
---|---|---|
Women 15-45 | 0.0E0 (-3.7E-8, 1.3E-7) | 7.1E-8 (1.3E-8, 1.6E-7) |
Population Group | Stroke Death Cases Per Person-Year Pooled Analysis Model | Stroke Death Per Person-Year Meta-Analysis Model |
---|---|---|
Women 15-45 | 0.0E0 (-3.1E-8, 8.0E-8) | 6.3E-8 (-1.3E-7, 2.4E-7) |
As a third variation on the 12 oz limitation, a scenario where all women of childbearing age consume exactly 12 oz of fish was examined. For this scenario, the methylmercury concentration was presumed to correspond to the market average of 0.086 ppm, resulting in an exposure of 4.3 µg/day of methylmercury. The impact of the advisory, relative to current levels of consumption, is presented in Table AB-12.
Population Percentile | Carrington (2000), Age of Talking | Cohen (2005b) IQ | Axelrad (2007) IQ |
---|---|---|---|
Average | -5.2E-3 (-7.2E-3, -4.0E-4) | -3.1E-3 (-2.3E-2, 2.3E-3) | -4.6E-3 (-8.1E-3, -1.6E-3) |
1st Percentile | -2.1E-2 (-3.4E-2, -7.4E-3) | -2.3E-2 (-1.8E-1, -1.5E-3) | -1.5E-2 (-3.2E-2, -5.4E-3) |
5th Percentile | -1.5E-2 (-2.1E-2, -3.6E-3) | -1.1E-2 (-8.4E-2, -8.3E-4) | -1.1E-2 (-2.0E-2, -4.1E-3) |
10th Percentile | -1.2E-2 (-1.7E-2, -2.1E-3) | -8.1E-3 (-6.0E-2, -1.7E-4) | -9.6E-3 (-1.7E-2, -3.4E-3) |
25th Percentile | -7.9E-3 (-1.1E-2, 0.0E0) | -6.8E-3 (-5.0E-2, 2.6E-4) | -7.0E-3 (-1.2E-2, -2.4E-3) |
Median | -4.8E-3 (-6.7E-3, 0.0E0) | -4.7E-3 (-3.6E-2, 1.3E-3) | -4.5E-3 (-7.7E-3, -1.5E-3) |
75th Percentile | -2.5E-3 (-3.6E-3, 0.0E0) | -3.0E-3 (-2.4E-2, 2.2E-3) | -2.6E-3 (-4.6E-3, -8.3E-4) |
90th Percentile | -4.5E-4 (-1.1E-3, 0.0E0) | -1.7E-3 (-1.3E-2, 3.5E-3) | -5.3E-4 (-1.3E-3, 0.0E0) |
95th Percentile | 1.8E-3 (0.0E0, 3.2E-3) | -2.0E-4 (-3.7E-3, 4.7E-3) | 1.7E-3 (4.7E-4, 3.3E-3) |
99th Percentile | 1.4E-2 (1.7E-3, 2.1E-2) | 1.9E-3 (1.2E-4, 9.5E-3) | 1.2E-2 (4.4E-3, 2.2E-2) |
The change in cardiovascular and stroke risk for the fixed 12 oz scenario are presented in Table AB-13 and Table AB-14, respectively.
Population Group | CHD Death Cases Per Person-Year Pooled Analysis Model | CHD Death Cases Per Person-Year Meta-Analysis Model |
---|---|---|
Women 15-45 | -1.4E-6 (-9.7E-6, 2.9E-6) | -1.7E-6 (-3.3E-6, -1.8E-7) |
Population Group | Stroke Death Cases Per Person-Year Pooled Analysis Model | Stroke Death Cases Per Person-Year Meta-Analysis Model |
---|---|---|
Women 15-45 | -3.9E-6 (-1.3E-5, 4.0E-6) | -2.2E-6 (-6.5E-6, 2.0E-6) |
As an exploration of potential unintended consequences of an advisory, the impact of reductions in the fish consumption in other population groups was modeled. Tables AB-15 through AB-18 present the estimate changes in CHD and cardiovascular death rates resulting from either a 10 percent reduction in the amount of fish consumed by all consumers or a one percent increase in the number of consumers who do not eat fish at all.
Population Group | CHD Death Cases Per Person-Year Pooled Analysis Model | CHD Death Cases Per Person-Year Meta-Analysis Model |
---|---|---|
Women 46+ | 2.9E-6 (-9.9E-6, 4.7E-5) | 2.3E-6 (3.5E-7, 5.1E-6) |
Men 15-45 | 1.2E-7 (-3.5E-7, 1.3E-6) | 9.2E-8 (1.4E-8, 2.1E-7) |
Men 46+ | 5.4E-6 (-7.9E-6, 1.1E-4) | 3.9E-6 (6.0E-7, 8.7E-6) |
Population Group | Stroke Death Cases Per Person-Year Pooled Analysis Model | Stroke Death Cases Per Person-Year Meta-Analysis Model |
---|---|---|
Women 46+ | 2.5E-6 (-1.5E-6, 3.2E-5) | 2.4E-6 (7.1E-7, 4.6E-6) |
Men 15-45 | 4.3E-8 (-2.8E-8, 3.4E-7) | 3.5E-8 (1.1E-8, 6.8E-8) |
Men 46+ | 2.8E-6 (-9.1E-6, 2.1E-5) | 1.9E-6 (6.0E-7, 4.0E-6) |
Population Group | CHD Death Cases Per Person-Year Pooled Analysis Model | CHD Death Cases Per Person-Year Meta-Analysis Model |
---|---|---|
Women 46+ | 1.2E-5 (-3.4E-5, 1.4E-4) | 2.2E-5 (4.0E-6, 4.3E-5) |
Men 15-45 | 4.5E-7 (-1.5E-6, 3.7E-6) | 8.9E-7 (1.6E-7, 1.7E-6) |
Men 46+ | 2.9E-5 (-3.5E-5, 2.2E-4) | 3.7E-5 (6.6E-6, 7.2E-5) |
Population Group | Stroke Death Cases Per Person-Year Pooled Analysis Model | Stroke Death Cases Per Person-Year Meta-Analysis Model |
---|---|---|
Women 46+ | 1.3E-5 (-1.2E-5, 5.7E-5) | 9.6E-6 (-2.2E-6, 2.2E-5) |
Men 15-45 | 2.1E-7 (-2.0E-7, 7.2E-7) | 1.4E-7 (-5.6E-8, 3.4E-7) |
Men 46+ | 1.2E-6 (-8.6E-5, 3.8E-5) | 7.3E-6 (-4.4E-6, 1.9E-5) |
Advisory Scenario: Limiting Species Without Limiting Amount Consumed
This scenario limited the species consumed without altering the amount consumed. Specifically, this putative advisory stipulates that only fish species with average concentrations below 12 ppb (see Table AA-2 in "methodology" Appendix A) are consumed by all women of childbearing age. This modification of the exposure model involved substituting fish species below the average concentration limit for species above the limit. The impact of the advisory, relative to current levels of consumption, is presented in Table AB-19. The presence of the negative values at the first percentile is a result of the possibility of substituting an individual fish from a species with a lower average concentration with a mercury level that higher than the individual fish that would have been consumed from the species with a higher average concentration. Since the amount of fish consumed is unchanged in this scenario, there is no impact on neurobehavioral benefits from fish or on cardiovascular endpoints, and as a result, the predicted effects with and without the inclusion of the Daniels benefit dose-response function are identical.
Population Percentile | Carrington (2000), Age of Talking | Axelrad (2007) IQ | Net Verbal ΔZ |
---|---|---|---|
Average | 1.1E-3 (0.0E0, 1.7E-3) | 1.0E-3 (0.0E0, 1.7E-3) | 1.1E-3 (0.0E0, 1.7E-3) |
1st Percentile | -3.9E-5 (0.0E0, 0.0E0) | -4.2E-5 (0.0E0, -6.8E-6) | -3.9E-5 (0.0E0, 0.0E0) |
5th Percentile | 0.0E0 (0.0E0, 0.0E0) | 0.0E0 (0.0E0, 0.0E0) | 0.0E0 (0.0E0, 0.0E0) |
10th Percentile | 0.0E0 (0.0E0, 0.0E0) | 0.0E0 (0.0E0, 0.0E0) | 0.0E0 (0.0E0, 0.0E0) |
25th Percentile | 2.5E-5 (0.0E0, 7.0E-5) | 2.9E-5 (0.0E0, 8.3E-5) | 2.5E-5 (0.0E0, 7.0E-5) |
Median | 3.0E-4 (0.0E0, 4.6E-4) | 3.0E-4 (0.0E0, 5.4E-4) | 3.0E-4 (0.0E0, 4.6E-4) |
75th Percentile | 1.1E-3 (0.0E0, 1.5E-3) | 1.0E-3 (0.0E0, 1.7E-3) | 1.1E-3 (0.0E0, 1.5E-3) |
90th Percentile | 2.8E-3 (0.0E0, 4.1E-3) | 2.5E-3 (0.0E0, 4.3E-3) | 2.8E-3 (0.0E0, 4.1E-3) |
95th Percentile | 4.8E-3 (0.0E0, 6.9E-3) | 4.1E-3 (0.0E0, 6.9E-3) | 4.8E-3 (0.0E0, 6.9E-3) |
99th Percentile | 1.3E-2 (0.0E0, 1.9E-2) | 1.1E-2 (0.0E0, 1.9E-2) | 1.3E-2 (0.0E0, 1.9E-2) |
Advisory Scenario: 50 Percent Increased Fish Consumption
This scenario examines the potential impact of an advisory that recommends increasing fish consumption. The model was modified by presuming an across the board increase in fish consumption of 50 percent. Table AB-20 and Table AB-21 present the estimated changes in CHD and Stroke Death relative to current levels of exposure, respectively.
Population Group | CHD Death Pooled Analysis Model | CHD Death Meta-Analysis Model |
---|---|---|
Women 15-45 | -1.7E-7 (-2.7E-6, 4.2E-7) | -3.4E-7 (-6.7E-7, -6.7E-8) |
Women 46+ | -4.1E-5 (-5.3E-4, 1.3E-4) | -1.1E-4 (-2.1E-4, -2.0E-5) |
Men 15-45 | -1.9E-6 (-1.4E-5, 5.8E-6) | -4.4E-6 (-8.6E-6, -8.0E-7) |
Men 46+ | -1.1E-4 (-1.0E-3, 1.4E-4) | -1.9E-4 (-3.6E-4, -3.3E-5) |
Population Group | Stroke Death Pooled Analysis Model | Stroke Death Meta-Analysis Model |
---|---|---|
Women 15-45 | -8.1E-7 (-3.0E-6, 6.0E-7) | -5.4E-7 (-1.3E-6, 2.2E-7) |
Women 46+ | -5.1E-5 (-1.9E-4, 5.5E-5) | -3.9E-5 (-1.0E-4, 2.5E-5) |
Men 15-45 | -8.0E-7 (-2.5E-6, 8.6E-7) | -6.0E-7 (-1.6E-6, 5.7E-7) |
Men 46+ | -4.4E-5 (-1.3E-4, 3.7E-5) | -3.1E-5 (-8.4E-5, 3.5E-5) |
Descriptions of Figures
- Figure AB-1: Quantile-Quantile Comparison of Model Estimates of Blood Mercury with Values from NHANES
Figure AB-1 is a quantile-quantile comparison for survey values from NHANES and model estimates for mercury in blood in women of childbearing age. Confidence intervals are given for the model estimates only. A line equality demarcates where the plotted values would if they were equal. The values plotted range from 0 to 25 micrograms per liter. The values below 5 micrograms per liter are all very close to the line of equality, indicating that the model estimates are very close to the survey values. At higher levels, above 5 micrograms per liter, the model estimates appear to be about 20% lower than the survey values. - Figure AB-2: Quantile-Quantile Comparison of Model Estimates of Hair Mercury with Values from NHANES
Figure AB-2 is a quantile-quantile comparison for survey values from NHANES and model estimates for mercury in hair in women of childbearing age. Confidence intervals are given for both the model estimates and the survey values. A line equality demarcates where the plotted values would if they were equal. The values plotted range from 0 to ppm. The model values are all lower than the survey values, with greater discrepancies at the higher percentiles. At levels below 1 ppm, the model estimates are less than 20% below the survey values. Above 1 ppm, the model estimates are about 40% lower than the survey values.