Biogeographic Ancestry in the African Descent and Glaucoma Evaluation Study (ADAGES): Association With Corneal and Optic Nerve Structure.
OBJECTIVE
We determined if quantitative measurements of biogeographic ancestry (BGA) correlate with variations in optic disc area, corneal thickness (CCT), and retinal nerve fiber layer (RNFL) thickness.


METHODS
Data were obtained from 656 participants in the African Descent and Glaucoma Evaluation Study (ADAGES) cohort who consented to BGA testing. Data for CCT, optic disc area, and RNFL thickness were obtained from subjects in the ADAGES study who also had participated in the current substudy. A total of 31 ancestry informative markers (AIMs) with large allele frequencies differences between populations was used to calculate admixture proportion (implemented in STRUCTURE). Correlations with BGA adjusted for diagnosis, age, and sex for CCT and optic disc area using the whole group and RNFL thickness adjusted for age and sex for the normal study participants were determined.


RESULTS
The mean percentage of African admixture was 79.6% in the self-described African Descent (AD) group and 3.5% in the European Descent (ED) group. Percent African ancestry was significantly correlated with CCT (ρ = -0.27, P < 0.0001) and disc area (ρ = 0.15, P < 0.0001), but only marginally associated with RNFL thickness (ρ = 0.20, P = 0.092) in adjusted models.


CONCLUSIONS
The BGA correlates with variation in ocular features that significantly differ across racial groups and that have been associated with the development of glaucoma. While BGA can provide an objective measurement of the biologic component of self-described race for ocular research, for most nongenetic epidemiologic studies, self-described race may adequately describe the associations with these ocular characteristics. (ClinicalTrials.gov number, NCT00221923.).
Department of Ophthalmology, University of Alabama at Birmingham, Birmingham, Alabama, United States.
Christopher A
CA
Girkin
Department of Psychiatry, University of California, San Diego, San Diego, California, United States.
Caroline M
CM
Nievergelt
Department of Ophthalmology, University of California, San Diego, San Diego, California, United States Pathway Genomics Corporation, San Diego, California, United States.
Jane Z
JZ
Kuo
Department of Psychiatry, University of California, San Diego, San Diego, California, United States.
Adam X
AX
Maihofer
Department of Ophthalmology, University of Alabama at Birmingham, Birmingham, Alabama, United States.
Carrie
C
Huisingh
Columbia University Medical Center, New York, New York, United States.
Jeffrey M
JM
Liebmann
Department of Ophthalmology, University of California, San Diego, San Diego, California, United States.
Radha
R
Ayyagari
Department of Ophthalmology, University of California, San Diego, San Diego, California, United States.
Robert N
RN
Weinreb
Department of Ophthalmology, New York Eye and Ear Infirmary, New York, New York, United States.
Robert
R
Ritch
Department of Ophthalmology, University of California, San Diego, San Diego, California, United States.
Linda M
LM
Zangwill
D000368:Aged; D044383:Black People; D015331:Cohort Studies; D003315:Cornea / Q000473:pathology*; D005260:Female; D005902:Glaucoma, Open-Angle / Q000208:ethnology* / Q000235:genetics / Q000473:pathology; D006801:Humans; D008297:Male; D008875:Middle Aged; D009412:Nerve Fibers / Q000473:pathology*; D009898:Optic Disk / Q000473:pathology*; D012044:Regression Analysis; D012165:Retinal Ganglion Cells / Q000473:pathology*
biogeographic ancestry; corneal thickness; optic disc; race; retinal nerve fiber layer