Ancestry-environment interactions and asthma risk among Puerto Ricans.
BACKGROUND
Puerto Ricans, an admixed population of African, European, and Native American ancestries, have the highest asthma prevalence, morbidity, and mortality rates of any United States' population. Although socioeconomic status (SES) is negatively correlated with asthma incidence in most populations, no such relationship has been identified among Puerto Ricans. We hypothesized that, in this admixed population, the association between SES and asthma may interact with genetic ancestry.


METHODS
We analyzed 135 Puerto Rican subjects with asthma and 156 control subjects recruited from six different recruitment centers in Puerto Rico. Individual ancestry for each subject was estimated using 44 ancestry informative markers. SES was assigned using the census tracts' median family income. Analyses of SES were based on the SES of the clinic site from which the subjects were recruited and on a subset of individuals on whom home address-based SES was available.


RESULTS
In the two (independent) analyses, we found a significant interaction between SES, ancestry, and asthma disease status. At lower SES, European ancestry was associated with increased risk of asthma, whereas African ancestry was associated with decreased risk. The opposite was true for their higher SES counterparts.


CONCLUSIONS
The observed interaction may help to explain the unique pattern of risk for asthma in Puerto Ricans and the lack of association with SES observed in previous studies when not accounting for varying proportions of ancestry.
Choudhry
Shweta
S
University of California, San Francisco, San Francisco, CA 94143-2911, USA.
Burchard
Esteban González
EG
Borrell
Luisa N
LN
Tang
Hua
H
Gomez
Ivan
I
Naqvi
Mariam
M
Nazario
Sylvette
S
Torres
Alphonso
A
Casal
Jesus
J
Martinez-Cruzado
Juan Carlos
JC
Ziv
Elad
E
Avila
Pedro C
PC
Rodriguez-Cintron
William
W
Risch
Neil J
NJ
D000293:Adolescent; D000328:Adult; D001249:Asthma / Q000208:ethnology* / Q000235:genetics*; D002648:Child; D005260:Female; D020022:Genetic Predisposition to Disease; D006630:Hispanic or Latino; D006801:Humans; D008297:Male; D011647:Puerto Rico / Q000208:ethnology; D012923:Social Class