Risk of dental aberrations in children in Beneris
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Question
Risk for dental aberrations in children describes the risk of developmental dental defects in children associated with exposure to PCBs and PCDD/Fs through fish ingestion.
Answer
Rationale
Risk for dental aberrations in children is represented as a function of parent variables and is indexed by variable age and gender. It applies to age groups 02yr and 218yr.
Causality
List of parents:
 Baseline risk of dental aberrations
 Intake of PCDD/F from fish in Beneris
 Intake of PCB from fish in Beneris
 ERF of dioxin on dental aberrations
 ERF of PCB on dental aberrations
Data
Exposureresponse factors of PCDD/Fs and PCBs on developmental dental defects (enamel defects of all permanent teeth except wisdom) correspond to concentrations of PCDD/Fs and PCBs in serum lipid. In order to measure the impact of child's exposure to PCDD/Fs and PCBs from fish on the health endpoint of interest the conversion of the average daily intake of these contaminants into the serum lipid concentration was used. Assuming that the concnetration of PCDD/Fs and PCBs in body lipids is at a steadystate this conversion is:
Fat_concnetration_PCDD/Fs(PCBs)(ng/kg body fat) = (0.001*Intake_PCDD/Fs(PCBs)_Fish(pg/kg bwday)*t(1/2)(days)*f)/(a*0.693*BF%(kg fat/kg bw))
where:
 Intake_PCDD/Fs(PCBs)_Fish is the average daily intake of PCDD/Fs (PCBs) from fish (all fish species),
 t(1/2) is the halflife (assumed to be 2737.5 days (7.5yr) for PCDD/Fs and 1460 days (4yr) for PCBs^{[1]} ^{[2]}),
 f is fraction absorbed from GI tract (assumed 0.95 for PCDD/Fs^{[3]} and 0.85 for PCBs ^{[4]}),
 BF% is the body fat percentage in children (see below),
 a is the proportion of daily dietary intake of PCDD/Fs (PCBs) that comes from fish (0.82 for PCDD/Fs and 0.89 for PCBs ^{[5]}).
Body fat percentage (BF%) in 02yr and 218yr males and females was estimated using the Deurnenberg formulas ^{[6]}. For children aged 15 years and younger the formula is 1.51*BMI(kg/m^2)0.7*Age(yr)3.6*Gender+1.4 and for individuals over 15 years the formula reads 1.2*BMI(kg/m^2)+0.23*Age(yr)10.8*Gender5.4, where Gender is 1 for males and 0 for females. For 218yr old children the combination of two Deurenberg formulas was used. In every age/sex group the BMI was estimated based on child's body weight and height as 1000*BW(kg)/(Height(cm)^2) and age was assumed to follow an uniform distribution (see population data ^{[7]}). Also the information about Spearmans's rank correlations between weight and age and between height and age in every age/sex group was used in the calculations. Moreover, for 218yr children, distributions of BF% were truncated with a miniumum BF% of 12% in females and with minimum of 3% in males.
Since the exposureresponse factors of PCDD/Fs and PCBs were derived for children in general the gender combined serum concentrations of PCDD/Fs and PCBs were estimated and used in the risk model. Proportions of males and females applied can be found here ^{[7]}.
Formula
Risk = 1/(1+exp(log(Baseline_risk_of_dental_aberrations/(1Baseline_risk_of_dental_aberrations))ERF_of_dioxin_on_dental_aberrations*(LOG_PCB_Fat_ConcentrationAverage_LOG_PCB_Fat_Concentration+LOG_Dioxin_Fat_ConcentrationAverage_LOG_Dioxin_Fat_Concentration)))
where LOG_PCB_Fat_Concentration = ln(PCB_Fat_Concentration+1) and LOG_Dioxin_Fat_Concentration = ln(Dioxin_Fat_Concentration+1)
See also
 Mocarelli et al EHP 2008: Dioxin Exposure, from Infancy through Puberty, Produces Endocrine Disruption and Affects Human Semen Quality
 Alaluusua et al 2004: Developmental dental aberrations after the dioxin accident in Seveso.
 ERF of dioxin
References
 ↑ H.Park et al. Congenerspecific approach to human PCB concentrations by serum analysis. Chemosphere, 2007.
 ↑ Doctoral thesis by H.Kiviranta. Exposure and human PCDD/F and PCB body burden in Finland. 2005.
 ↑ Dahl et al. Absorption of polychlorinated biphenyls dibenzopdioxins and dibenzofurans by breastfed infants. Chemosphere, 1995.
 ↑ Juan et al. An inputoutput balance study for PCBs in humans. Environment International, 2002.
 ↑ M.L.Wiborg, H.K.Knutsen, O.Andersson, A.Buchert, T.Cederberg, P.O.Darnerud, A.Hallikainen, H.Kiviranta, K.Olafsdottir, K.Peters, EU maximum levels for dioxins and dioxinlike PCBs  impact exposure and food supply in the Nordic countries (table A4 in the Appendix)
 ↑ http://www.halls.md/bmi/fat.htm
 ↑ ^{7.0} ^{7.1} Population of Finland years 1980  2007. http://en.opasnet.org/w/Image:Population_of_Finland_years_19802007.xls