Epidemiology

ToxStrategies professionals have decades of experience in conducting original research, critically evaluating epidemiologic studies, and using human health data for risk assessments and causation evaluations. We are recognized as experts in the field of epidemiology. Areas of experience in this field include the following.

Original research

  • Study protocol and Institutional Review Board applications
  • Study recruitment materials and informed-consent forms
  • Exposure assessment strategy
    • Use of air monitoring data to characterize residential exposures from point and mobile sources
    • Use of industrial hygiene data (personal, general area) and occupational histories to develop cohort-specific job exposure matrix
  • Case ascertainment
  • Statistical tests and models
  • Examples:
    • Longitudinal asthma study of air pollution effects on children
    • Cohort mortality studies of workers exposed to hexavalent chromium
    • Cohort mortality study of Vietnam veterans exposed to dioxin
    • Cross-sectional survey of workers exposed to beryllium
    • Cross-sectional survey of goitrogens and thyroid effects
    • Repeated open-application testing for allergic contact dermatitis due to hexavalent chromium

Application of epidemiologic data for dose-response modeling and risk assessment

  • Inhalation risk assessment of hexavalent chromium and lung cancer
    • Cox regression models
    • Poisson regression models
  • Inhalation risk assessment of beryllium and chronic beryllium disease
    • Benchmark dose models
    • Spline regression models

Critical evaluations of epidemiologic data and studies

  • Study design and limitations
    • Presence of bias (selection bias, observation bias, misclassification)
    • Uncontrolled confounding and effect modification
    • Review of bias-adjusted analyses for random error, accuracy, and precision
    • Generalizability
  • Technical comments to agencies and entities, including ACGIH, ECHA, EPA, OEHHA, OSHA, NIOSH, and SCOEL
  • Weight-of-evidence reviews
  • Systematic reviews and meta-analyses
    • Risk of bias for internal validity
    • Presence of publication bias and heterogeneity (funnel plots, trim and fill tests)
    • Sensitivity analyses
    • Body-of-evidence integration
  • Evidence-based causation analyses
    • Bradford-Hill criteria
    • Causal diagrams (component causes)

Software tools

  • R
  • SEER*Stat
  • Meta Data Viewer
  • Epi Info
  • GIS

Databases used

  • Surveillance, Epidemiology, and End Results Program (SEER)
  • National Health and Nutrition Examination Survey (NHANES)
  • National Death Index (NDI)
  • California Pesticide Illness Surveillance Program
  • Asthma surveillance
  • Birth defects registries