Measurement Error in Population Health Inequity Research using Novel Biomeasures-Supplement
Investigators: Arline T. Geronimus, Javier Rodriguez
Funding: National Institute on Aging, 2014-2019 (3 R01 AG 047167 01 S1)
In the parent project to this supplement, we are addressing the question of whether DNA from blood or saliva banked with large population-based data sets is valid for use in population health studies of telomere length (TL) – an intriguing new biomeasure of stress-mediated health, development, and aging – and, if so, what sample sizes are needed. This component project extends the analytic aims to determine whether blood DNA collected through finger prick blood spot (DBS) is valid for estimating TL in health disparities research.
The state-of-the-art approach to measuring TL is via leukocyte-derived DNA extracted from fresh venous blood samples. Data collection activities that include venous blood draws, molecular measurements and the broad swath of social, environmental, behavioral, and health variables needed is costly, requires clinical expertise for blood collection, and takes years before data can be analyzed. However, extant population-based data collections are increasingly isolating blood DNA for storage in specimen repositories either through DBS or after the cells have been transformed and immortalized using Epstein-Barr Virus (EBV); or storing DNA in saliva. The critical unanswered question is whether the error introduced in these TL measures is random or systematic with respect to original TL or to populations of interest in disparities studies.
Because until recently it was thought that DBS was unsuitable for TL measurement, we did not include estimating its validity in the parent project. However, the question of whether DBS might be suitable has been re-opened in the field and some researchers have begun to use it. We will estimate the validity of using DNA extracted from blood cells collected via DBS to estimate population differences in TL in samples stratified by key axes of comparison – race/ethnicity, socioeconomic status, stress-level, and neighborhood – and using sophisticated measurement error statistical techniques. Findings can be applied immediately toward increasing the pace of health disparities research, whatever the conclusion on the validity of using DBS to measure TL.