Table 1 Summary of input parameters and assumptions in the Monte Carlo simulation of the FIS results adjusted for outcome misclassification, selection bias and confounding

Observed exposure: mercury concentration in cord blood (mg/L),

Mean_x = 31.99, SD_x = 25.53

Budtz-Jorgensen et al. 2005; based on median and 99^th percentile in a log-normal distribution (39)

Observed outcome: Score on Boston naming test

Mean_y = 25, SD_y = 5.3

Mean: Grandjean et al. 1997 (4), SD from Budtz-Jorgensen et al. 2004

Observed b₁

N (-0.019, 0.0063)

Budtz-Jorgensen et al. 2005 (39)

Observed b₀

= 25 - 31.99 × Observed b₁

Derived using standard linear regression formula (b₀ = -b₁ )

P1: proportion of exposed with a1 (negative) adjustment

U (0.1,0.3)

Hypothetical (no data available)

P2: proportion of exposed with a2 (positive) adjustment

U (0.1,0.3)

a1: relative adjustment in outcome for proportion p1 of subjects

U (0.0,0.31)

Hypothetical (no data available), limits chosen to allow BNT score vary between 0 and 60

a2: relative adjustment in outcome for proportion p2 of subjects

U (0.0,0.48)

Observed exposure: mercury concentration in cord blood (mg/L),

See above

10,000 vectors (Mean_y, Sd_y, b₀, b₁) adjusted for information bias

Output of Information Bias module

Number of subjects included in the analysis

866

Grandjean et al. 1997; N in Boston Naming Test "no cues" (4)

Number of eligible subjects

1362

Calculated as 1022/0.75 (1022 are ~75% of all births (44)

Number of subjects excluded from the analysis

496

Derived as 1362-866

Relative difference between mean exposure of subjects not included and mean exposure of included subjects

U (-5%,5%)

Hypothetical (no data available)

Relative difference between mean outcome of subjects not included and mean outcome of included subjects

U (-10%,10%)

Hypothetical (no data available)

Slope multiplier (to get to slope of non-included subjects)

U (0,2)

Hypothetical (no data available)

10,000 vectors (Mean_x, SD_x, Mean_y, SD_y, b₀, b₁) adjusted for information and selection bias

Output of Selection Bias Module

Pearson correlation between confounder (WAIS) and exposure

U (-0.5, 0.5)

Hypothetical (no data available)

Pearson correlation between confounder (WAIS) and outcome

U (0.2, 0.8)

Hypothetical (no data available)