Ethnicity and Neonatal Lupus Erythematosus Manifestations Risk in a Large Multi-Ethnic Cohort.

OBJECTIVE To evaluate the association between ethnicity and neonatal lupus erythematosus (NLE), as well as specific NLE manifestations in a large multi-ethnic population. METHODS We conducted a cohort study of the children (≤1 year of age) seen in the NLE clinic at SickKids, between January 2011 and April 2019. The cohort was divided into European, non-European and Mixed European-Non-European groups according to parent reported child's ethnicity (Canada census categories). Outcomes were NLE and specific NLE manifestations (cardiac, cutaneous, cytopenias, transaminitis and macrocephaly). The frequency of NLE and specific manifestations were compared between ethnic groups (Fisher's exact test). We tested the association between ethnicity and 1) NLE risk and 2) specific NLE manifestations with logistic regression models, including covariates for child's sex, maternal rheumatic disease status during pregnancy, and maternal use of antimalarials during pregnancy (multiple comparisons threshold p-value<0.008). RESULTS We included 324 children born to 270 anti-Ro antibody positive mothers. Median age at first visit: 1.8 months (IQR: 1.4, 2.3 months). Median follow-up time: 12 months (IQR: 2,24months). The majority were non-European (48%), with 34% European, and 18% Mixed European-Non-European. There was no significant association between non-European ethnicity (OR 1.14, 95% CI:0.69-1.89, p=0.59), Mixed European-Non-European ethnicity (OR 1.06, 95% CI:0.55-2.06, p=0.84) and NLE risk compared with European ethnicity. We also did not find an association between ethnicity and specific NLE manifestations, in univariate or multivariable adjusted models. CONCLUSION In a large multiethnic cohort, there was no association between child's ethnicity and NLE risk, nor specific NLE manifestations.