ERF of methyl mercury on intelligence quotient: Difference between revisions
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'''Scope'''<br> | '''Scope'''<br> | ||
''' | '''[[ERF]] of methyl mercury on intelligence quotient''' describes the quantitative relationship between exposure to (prenatal) methyl mercury exposure and intelligence quotient (IQ) score (in children). | ||
== Definition == | == Definition == | ||
=== Causality === | === Causality === | ||
List of parents: | List of parents: | ||
* None | * None | ||
=== Data === | === Data === | ||
'''Actual content''' | |||
Prenatal MeHg exposure sufficient to increase the concentration of mercury in maternal hair at parturition by 1 ug/g decreases IQ by 0.7 points (min and max 0 and 1.5, respectively). | |||
=== Unit == | |||
'''Narrative description''' | |||
Every 1 ug/g of methylmercury in mothers hair decreases IQ of a child by 0.7 points. Study by Cohen et al<ref name="cohenMMVa">Methyl mercury: Cohen et al 2005a</ref> finds that prenatal MeHg exposure sufficient to increase the concentration of mercury in maternal hair at parturition by 1 ug/g decreases IQ by 0.7 points. The paper identifies important sources of uncertainty influencing this estimate, concluding that the plausible range of values for this loss is 0 to 1.5 IQ points.<ref name="cohenMMVa"/> | |||
A triangular distribution with parameters: min = 0, mode = 0.7 and max = 1.5 was created. Distribution by author judgement. {{disclink|Author judgement about the chosen distribution}} | |||
This variable includes conversion from mercury intake to mercury concentration in hair. Firstly, WHO(1990) suggests the use of a single-compartment model, through which the steady-state Hg concentration in blood (C) in ug/l is related to the average daily dietary intake (d) in ug of Hg, as follows: C = 0.95 * d. Secondly, blood mercury was converted to total hair mercury using a 1:250 ratio (New Zealand and Seychilles Island studies) and an assumption of equivalent maternal and cord levels.<ref>Methyl mercury: Bidone_et_al(2004)</ref> {{disclink|Toxicologicy of methylmercury}} | |||
=== Formula === | |||
Analytica_id: | |||
<Anacolde>triangular(-1.5,-0.7,0)*Blood_to_hair</Anacode> | |||
== Unit == | |||
IQ points / 1 ug/g increase in maternal hair | |||
== Result == | == Result == | ||
0.7333 | |||
==References== | |||
<references/> | |||
Revision as of 12:32, 9 February 2008
Scope
ERF of methyl mercury on intelligence quotient describes the quantitative relationship between exposure to (prenatal) methyl mercury exposure and intelligence quotient (IQ) score (in children).
Definition
Causality
List of parents:
- None
Data
Actual content
Prenatal MeHg exposure sufficient to increase the concentration of mercury in maternal hair at parturition by 1 ug/g decreases IQ by 0.7 points (min and max 0 and 1.5, respectively).
Narrative description
Every 1 ug/g of methylmercury in mothers hair decreases IQ of a child by 0.7 points. Study by Cohen et al[1] finds that prenatal MeHg exposure sufficient to increase the concentration of mercury in maternal hair at parturition by 1 ug/g decreases IQ by 0.7 points. The paper identifies important sources of uncertainty influencing this estimate, concluding that the plausible range of values for this loss is 0 to 1.5 IQ points.[1]
A triangular distribution with parameters: min = 0, mode = 0.7 and max = 1.5 was created. Distribution by author judgement. D↷
This variable includes conversion from mercury intake to mercury concentration in hair. Firstly, WHO(1990) suggests the use of a single-compartment model, through which the steady-state Hg concentration in blood (C) in ug/l is related to the average daily dietary intake (d) in ug of Hg, as follows: C = 0.95 * d. Secondly, blood mercury was converted to total hair mercury using a 1:250 ratio (New Zealand and Seychilles Island studies) and an assumption of equivalent maternal and cord levels.[2] D↷
Formula
Analytica_id:
<Anacolde>triangular(-1.5,-0.7,0)*Blood_to_hair</Anacode>
Unit
IQ points / 1 ug/g increase in maternal hair
Result
0.7333