The research community has focused considerable attention on analytical methods development (negative binomial models, simultaneous equations, etc.), on better experimental designs (before after studies, comparison sites, etc.), on improving exposure measures, and on model specification improvements (additive terms, non-linear relations, etc.).
Future studies should focus on improving exposure measurements, e.g., estimating or measuring traffic-related pollutants near homes and schools, and including time/activity patterns in the prediction models.
Researchers must think critically about what can be measured, when to measure it, and the associated costs, because improved exposure assessment will lead to decreased measurement error and significantly increased study power (Armstrong 1996; London 2007; Wong et al. 2003).
Here a biomarker of exposure was defined as a biological measure which is correlated with the quantity of the xenobiotic ingested, resulting in improved exposure classification over more traditional approaches [ 2].
Recent studies have attempted to improve exposure assessment by using individual exposure measures combining routinely collected water system THM measurements with a measure of ingestion, such as number of glasses or water drank per day.
There needs to be a shift from what scientists can readily measure to what truly needs to be measured to improve exposure assessments, evaluations of health impacts, and regulations.
Therefore, including these characteristics in the PDD model did not significantly improve the exposure measure or change which subjects were considered exposed and to what level they were exposed.
Since 1989, advancements in the technology to analyze BCd and UCd have improved the reliability of human exposure measures (Tsalev 1995); however, the use of these biomarkers has been inconsistent across epidemiological studies of HTN and BP.
Correcting exposure measures and improving study designs with this approach may permit mitigating biases related to selective daily mobility.
