Factors influencing findings across studies (e.g. definition and validation of UGIC, exposure assessment, analysis of new vs prevalent users) and the scarce data on the effect of dose and duration of use of NSAIDs and on concurrent use of other medications need to be addressed in future studies, including SOS.
The present analyses indicate that personal exposure to the EC portion of PM2.5, which in our exposure assessment analysis was strongly affected by diesel exhaust emissions in this locale (Spira-Cohen et al. 2010), is most associated with several adverse respiratory outcomes in a group of inner-city elementary school children with asthma.
Risk assessment, exposure assessment, and analysis of occupa tional cohort studies are examples of the methodologic issues addressed.
Data categories comprised referencing, study design, subject selection, exposure assessment, statistical analysis, and results.
JW, PAJ, TW, and VV provided technical input to data collection, exposure assessment, data analysis, and manuscript preparation.
EDF participated in the study design and in the manuscript preparation and coordinated the exposure assessment (laboratory analysis).
JMC contributed to the study design, data collection and exposure assessment, statistical analysis and review of the manuscript.
A standard data abstraction form was prepared and piloted to collect relevant data related to referencing, study design, subject selection, exposure assessment, statistical analysis, and results.
The impact on the findings across studies related to varying study design approaches — including choices in the definition and validation of UGIC, exposure assessment and analysis of new or prevalent users — should be taken into account when designing new studies.
For each study, we obtained information on the estimated effect size to calculate the standardized mean difference (unitless) and determined the potential for errors in exposure assessment and analysis of each of the biomarkers, for total and stratified formal meta-analyses.
The panel was comprised of eight academic specialists (two of the authors, K.S. and S.H.L., served as panel members, and the other three, D.M., H.B., and P.J.L., served as staff) from five local universities with a range of expertise, including toxicology, epidemiology, exposure assessment, risk analysis, occupational medicine, pediatric pulmonology, and chemical engineering.
