Ethnicity and Neonatal Lupus Erythematosus Manifestations Risk in a Large Multiethnic Cohort.

Objective: To evaluate the association between ethnicity and neonatal lupus erythematosus (NLE), as well as specific NLE manifestations in a large multiethnic population.

Methods: We conducted a cohort study of the children (≤ 1 yr of age) seen in the NLE clinic at The Hospital for Sick Children (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 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 < 0.008).

Results: We included 324 children born to 270 anti-Ro antibody-positive mothers. Median age at first visit was 1.8 (IQR 1.4-2.3) months, and median follow-up time was 12 (IQR 2-24) months. The majority was non-European (48%), with 34% European, and 18% mixed European-non-European. There was no significant association between non-European ethnicity (OR 1.18, 95% CI 0.71-1.94, = 0.51), mixed European-non-European ethnicity (OR 1.13, 95% CI 0.59-2.16, = 0.70), 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 a child's ethnicity and NLE risk or specific NLE manifestations.