For prospective analyses (starting 1 year after the age at the time of the C8 Health Project), estimates were calibrated to the measured serum PFOA concentrations using Bayesian calibration, with measurements weighted more heavily for estimates closer in time to the measurements.
To account for the uncertainty in the origin of the measurement, the extended likelihood data association method [10] incorporates local attribute information of measurements weighted by probabilistic data association (PDA) for correctly identifying the measurement from the target as against the clutter.
For each patient, the average variance was calculated over the different slice measurements, weighted with the number of pixels.
Using these posteriors, the updated value x ′ p r is given by the mean of the technical replicate measurements, weighted by their posteriors (31) x ′ p r = ∑ i x p r i p (i | x p r i, x p r, σ r 2, ρ r ) ∑ i p (i | x p r i, x p r, σ r 2, ρ r ).
The two key parameters are identified using the measurement error weighted least squares linear regression.
In models using arsenic exposure as a continuous variable and accounting for exposure measurement error (weighted by the inverse of exposure variance), an IQR increase in blood arsenic concentration was associated with 1.65 times higher odds of impaired GTT (> 140 mg/dL) (95% CI, 1.52 1.79) and with 1.73 higher odds of impaired GTT (> 130 mg/dL) (95% CI, 1.61 1.87) (Table 2).
A moderate agreement was found between reported tea drinking temperature and actual temperature measurements (weighted κ 0.49).
Each virtual subject's relative contribution to virtual population measurements is weighted by a virtual subject specific prevalence weight; a simple weighting scheme was applied by which each virtual subject was assigned a weight of either 1 or 0 to optimize the fit to clinical data distributions.
Fractions for the different measurements were weighted into snap cap vials and stored in the fridge until measurement.
