Objective: The goal of the present investigation is to analyze thymus, brain, heart, liver, and kidney weights in SIDS victims compared to controls.
Background: Epidemiologic risk factors for SIDS (eg, male gender, genetic, obstetric, environmental, smoke exposure, nonbreastfeeding, etc.) are consistent with an infectious process underlying many of these deaths.
Methods: Data from autopsy reports on 585 SIDS victims and comparison deaths (n = 294 control, n = 291 SIDS) were analyzed. Cases were obtained from Australia (n = 184 controls, n = 98 SIDS) and Russia (n = 122 controls, n = 181 SIDS). Log10 transform of thymus and other organ weights was computed because variables were skewed. Multivariate analysis of variance (MANOVA) of standardized log values were age-adjusted by multivariate analysis of covariance (MANCOVA). The standardized log10 thymus residual adjusted for age, brain and liver weights was computed for the final analysis.
Results: After controlling for age by MANCOVA, thymus, body, brain and liver weights were significantly higher among SIDS compared to non-SIDS victims. The largest difference as between covariate-adjusted log10 non-SIDS thymus weight differed (mean = 1.423, 95% CI: 1.393-1.452) and log10 non-SIDS thymus weight (mean = 1.269, 95% CI: 1.243-1.294) were significantly different (P < .0001). Heart weight was significantly lower in SIDS victims.
Discussion: When adjusted for confounders (age, body, and organ weights), SIDS victims have a significantly heavier thymus and brain compared to non-SIDS controls who died of trauma. This finding supports previously published studies that link infection to SIDS deaths.
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