Women exposed to trauma and post traumatic stress have an almost three-fold increased risk of lupus, new research shows.
The longitudinal US study of almost 55,000 women participating in the Nurse’s study identified 73 cases of incident lupus during the 24-year follow-up.
Lifetime exposure to trauma, regardless of PTSD symptoms, was strongly associated with the development of lupus (Hazard Ratio 2.87) as was probable PTSD (HR 2.94).
The study included 15 types of traumatic events such as serious motor vehicle accidents or sexual abuse but excluded trauma caused by medical illness.
Adjustment for smoking, BMI and oral contraceptive use only slightly attenuated the association.
The researchers said their findings did not appear to result from either confounding or reverse causality, whereby lupus caused trauma exposure or PTSD.
Their findings were consistent when trauma and PTSD exposure were time lagged or when characterised at baseline, substantially prior to most SLE diagnoses.
“Moreover, we found that SLE diagnosis itself did not predict risk of subsequently developing PTSD. These results strengthen evidence that the experience of trauma and PTSD may increase risk of subsequent SLE.”
Professor Eric Morand, head of the Monash Health Rheumatology Unit, said SLE was dependent on a combination of environmental and genetic factors.
“Most physicians have seen cases where a history of psychological trauma is followed, at a variable interval, by the development of autoimmune disease,” he told the limbic.
“The immune system has been known for decades to be powerfully modified by stress, including through the effects of stress-induced changes in glucocorticoid levels but also multiple other endocrine factors and neurotransmitters. It is therefore highly biologically plausible for psychological stress to be a contributing factor to the development of SLE, either in relation to susceptibility per se or timing.”
He said it was important to acknowledge that the absolute risk of SLE in people with a history of PTSD appeared to be very low.
“Likewise, aside from providing potential explanations to patients about how they became susceptible to SLE, no obvious intervention to assist in the treatment of SLE patients is apparent from this study.”
Professor Morand said the direct effects of stress on emerging biological pathways such as type I interferons will be important future topics for lupus research.