Risk of dental aberrations in children in Beneris

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Scope

Risk for dental aberrations in children describes the risk of developmental dental defects in children associated with exposure to PCBs and PCDD/Fs though fish ingestion in the Finnish population.

Definition

Risk for dental aberrations in children is represented as a function of parent variables and is indexed by variable age. It applies to age groups 0-2yr and 2-18yr.

Causality

List of parents:

Data

Exposure-response 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 steady-state this conversion is:

Fat_concnetration_PCDD/Fs(PCBs)(ng/kg body fat) = (0.001*Intake_PCDD/Fs(PCBs)_Fish(pg/kg bw-day)*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 half-life (assumed to be 2337.5 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 0-2yr and 2-18yr 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*Gender-5.4, where Gender is 1 for males and 0 for females. For 2-18yr 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]).

Since the exposure-response 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/(1-Baseline_risk_of_dental_aberrations))-ERF_of_dioxin_on_dental_aberrations*(LOG_PCB_Fat_Concentration-Average_LOG_PCB_Fat_Concentration+LOG_Dioxin_Fat_Concentration-Average_LOG_Dioxin_Fat_Concentration)))

Unit

Result

References

  1. ↑ H.Park et al. Congener-specific approach to human PCB concentrations by serum analysis. Chemosphere, 2007.
  2. ↑ Doctoral thesis by H.Kiviranta. Exposure and human PCDD/F and PCB body burden in Finland. 2005.
  3. ↑ Dahl et al. Absorption of polychlorinated biphenyls dibenzo-p-dioxins and dibenzofurans by breast-fed infants. Chemosphere, 1995.
  4. ↑ Juan et al. An input-output balance study for PCBs in humans. Environment International, 2002.
  5. ↑ 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 dioxin-like PCBs - impact exposure and food supply in the Nordic countries (table A4 in the Appendix)
  6. ↑ http://www.halls.md/bmi/fat.htm
  7. ↑ 7.0 7.1 Population of Finland years 1980 - 2007. http://en.opasnet.org/w/Image:Population_of_Finland_years_1980-2007.xls
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