Epidemiology

In response to citizens' concerns, Gradient investigated the incidence rate of several cancers in residents living near a municipal landfill to determine whether it was elevated relative to rates in the general population. We described the findings to city officials and residents at public meetings.

Gradient modeled chlorinated solvents exposure from drinking water and showering, and we used questionnaire data on disease status and other population characteristics to assess the association between exposures and disease rates in a community living near a Superfund site.

Gradient conducted a meta-analysis and meta-regression of data on airway hyper responsiveness from clinical studies of asthmatic volunteers exposed to NO₂ while exercising or at rest.

Gradient analyzed the statistical basis for a dose-response relationship between blood lead and neurocognitive impairment. We evaluated the extent to which the relationship could be ascribed to the statistical elements of the modeling or was indicative of the underlying relationship between the two parameters.

Gradient conducted a weight-of-evidence evaluation of the association between ozone exposure and cardiovascular effects. We developed and applied a methodological framework to review epidemiology, toxicity, and mechanistic literature to determine whether there was sufficient evidence of a causal association.