Growing evidence indicates a reciprocal relationship between systemic inflammation and stress exposure, as indicated by high rates of co-morbidity between PTSD and several autoimmune and inflammatory disorders (AIID). The prevalence of both conditions is higher in women than men, however few studies have assessed sex-differences in the prevalence of AIID in individuals with PTSD.
Here, we examined the prevalence of AIID in a large cohort of men and women with PTSD and in a subgroup of individuals with comorbid depression, given that this disorder is also associated with a pro-inflammatory state.
We conducted a retrospective cohort study of 5,765 patients diagnosed with PTSD enrolled in the MGB Biobank between 2010 and 2021. Of those, patients aged 18-49, with no lifetime diagnosis of bipolar disorder and schizophrenia were included in the analysis. Chi-square tests were used to test differences in the prevalence of comorbid AIID among men and women with PTSD (n= 957). Analyses were repeated in the subgroup of individuals with comorbid depression.
Compared to an overall prevalence between 5-9% in the general population, the prevalence of AIID in our study sample was approximately 57% (60% in women vs 50% in men). Women with PTSD were more likely to have an AIID than men with PTSD (p= 0.003). Similar results were obtained when considering exclusively systemic autoimmune disorders (p= 0.0001) and in the subgroup of individuals (n=493 female; n=178 male) with comorbid depression (p= 0.006). Finally, women with comorbid depression showed higher rates of AIID than women with PTSD only (68% vs 60%).
Our study extends prior research on the link between PTSD and AIID. We showed that the magnitude of this association was greater in women compared to men and was further exacerbated by comorbid depression, suggesting a common ethiopathogenetic mechanism among these disorders