Influence of geolocation and ethnicity on the phenotypic expression of primary Sjögren’s syndrome at diagnosis in 8310 patients: A cross-sectional study from the Big Data Sjögren’s Project Consortium

Objectives To analyse the influence of geolocation
and ethnicity on the clinical presentation of primary
Sjögren’s syndrome (SjS) at diagnosis.
Methods The Big Data Sjögren Project Consortium is
an international, multicentre registry designed in 2014.
By January 2016, 20 centres from five continents were
participating. Multivariable logistic regression analyses
were performed.
Results We included 7748 women (93%) and 562
men (7%), with a mean age at diagnosis of primary SjS
of 53 years. Ethnicity data were available for 7884
patients (95%): 6174 patients (78%) were white, 1066
patients (14%) were Asian, 393 patients (5%) were
Hispanic, 104 patients (1%) were black/African-
American and 147 patients (2%) were of other
ethnicities. SjS was diagnosed a mean of 7 years earlier
in black/African-American compared with white patients;
the female-to-male ratio was highest in Asian patients
(27:1) and lowest in black/African-American patients
(7:1); the prevalence of sicca symptoms was lowest in
Asian patients; a higher frequency of positive salivary
biopsy was found in Hispanic and white patients.
A north-south gradient was found with respect to a
lower frequency of ocular involvement in northern
countries for dry eyes and abnormal ocular tests in
Europe (OR 0.46 and 0.44, respectively) and Asia (OR
0.18 and 0.49, respectively) compared with southern
countries. Higher frequencies of antinuclear antibodies
(ANAs) were reported in northern countries in America
(OR=1.48) and Asia (OR=3.80) while, in Europe,
northern countries had lowest frequencies of ANAs
(OR=0.67) and Ro/La (OR=0.69).
Conclusions This study provides the first evidence of a
strong influence of geolocation and ethnicity on the
phenotype of primary SjS at diagnosis.