Adjustment for Urinary Creatinine or Serum Lipids for Analytes Assayed in Pooled Specimens

Area of Science:

• Environmental epidemiology
• Biomarker analysis
• Case-control studies

Background:

• Specimen pooling in case-control studies offers cost-effectiveness and specimen conservation for expensive biomarker assays.
• Pooling designs maintain estimation precision and can increase participant numbers for a fixed assay cost.
• A key limitation has been the inability to adjust for urinary creatinine or serum lipids in pooled samples.

Purpose of the Study:

• To develop practical strategies for adjusting pooled biospecimens for urinary creatinine and serum lipids.
• To enable valid biomarker analysis in pooled urine and serum samples within case-control studies.

Main Methods:

• Developed strategies involving differential dilution or unequal aliquot pooling based on individual specimen adjustment factors.
• Incorporated methods to account for factors influencing creatinine levels.
• Utilized simulations under various causal scenarios to evaluate the strategies.

Main Results:

• The proposed strategies effectively estimate the same adjusted association parameters as individual specimen assays.
• Simulations confirmed the validity and performance of the developed adjustment methods.

Conclusions:

• Implementing these strategies significantly enhances the efficiency of case-control studies using pooled biospecimens.
• Facilitates cost-effective analysis of expensive-to-assay biomarkers in large-scale epidemiological research.