Health Equity Implications of Missing Data Among Youths With Childhood-Onset Systemic Lupus Erythematosus: A Proof-of-Concept Study in the Childhood Arthritis and Rheumatology Research Alliance Registry.

OBJECTIVE: Health disparities in childhood-onset systemic lupus erythematosus (SLE) disproportionately impact marginalized populations. Socioeconomically patterned missing data can magnify existing health inequities by supporting inferences that may misrepresent populations of interest. Our objective was to assess missing data and subsequent health equity implications among participants with childhood-onset SLE enrolled in a large pediatric rheumatology registry. METHODS: We evaluated co-missingness of 12 variables representing demographics, socioeconomic position, and clinical factors (e.g., disease-related indices) using Childhood Arthritis and Rheumatology Research Alliance Registry childhood-onset SLE enrollment data (2015-2022; n = 766). We performed logistic regression to calculate odds ratios (ORs) and 95% confidence intervals (95% CIs) for missing disease-related indices at enrollment (Systemic Lupus Erythematosus Disease Activity Index 2000 [SLEDAI-2K] and/or Systemic Lupus International Collaborating Clinics/American College of Rheumatology Damage Index [SDI]) associated with data missingness. We used linear regression to assess the association between socioeconomic factors and SLEDAI-2K at enrollment using 3 analytic methods for missing data: complete case analysis, multiple imputation, and nonprobabilistic bias analyses, with missing values imputed to represent extreme low or high disadvantage. RESULTS: On average, participants were missing 6.2% of data, with over 50% of participants missing at least 1 variable. Missing data correlated most closely with variables within data categories (i.e., demographic). Government-assisted health insurance was associated with missing SLEDAI-2K and/or SDI scores compared to private health insurance (OR 2.04 [95% CI 1.22, 3.41]). The different analytic approaches resulted in varying analytic sample sizes and fundamentally conflicting estimated associations. CONCLUSION: Our results support intentional evaluation of missing data to inform effect estimate interpretation and critical assessment of causal statements that might otherwise misrepresent health inequities.

Interaction between mono-(2-ethylhexyl) phthalate and retinoic acid alters Sertoli cell development during fetal mouse testis cord morphogenesis.

Phthalic acid esters (phthalates) are a class of industrial chemicals that cause developmental and reproductive toxicity, but there are significant gaps in knowledge of phthalate toxicity mechanisms. There is evidence that phthalates disrupt retinoic acid signaling in the fetal testis, potentially disrupting control of spatial and temporal patterns of testis development. Our goal was to determine how a phthalate would interact with retinoic acid signaling during fetal mouse testis development. We hypothesized that mono-(2-ethylhexyl) phthalate (MEHP) would exacerbate the adverse effect of all-trans retinoic acid (ATRA) on seminiferous cord development in the mouse fetal testis. To test this hypothesis, gestational day (GD) 14 C57BL/6 mouse testes were isolated and cultured on media containing MEHP, ATRA, or a combination of both compounds. Cultured testes were collected for global transcriptome analysis after one day in culture and for histology and immunofluorescent analysis of Sertoli cell differentiation after three days in culture. ATRA disrupted seminiferous cord morphogenesis and induced aberrant FOXL2 expression. MEHP alone had no significant effect on cord development, but combined exposure to MEHP and ATRA increased the number of FOXL2-positive cells, reduced seminiferous cord number, and increased testosterone levels, beyond the effect of ATRA alone. In RNA-seq analysis, ATRA treatment and MEHP treatment resulted in differential expression of genes 510 and 134 genes, respectively, including 70 common differentially expressed genes (DEGs) between the two treatments, including genes with known roles in fetal testis development. MEHP DEGs included RAR target genes, genes involved in angiogenesis, and developmental patterning genes, including members of the homeobox superfamily. These results support the hypothesis that MEHP modulates retinoic acid signaling in the mouse fetal testis and provide insight into potential mechanisms by which phthalates disrupt seminiferous cord morphogenesis.