Around one in ten women worldwide have endometriosis. This common condition causes tissue similar to the lining of the uterus to grow in other parts of the body. This can result in painful periods, chronic pain and even infertility.
Author
- Marika Rostvall
PhD Candidate, Epidemiology, Karolinska Institutet
Yet despite how common endometriosis is, there's currently no cure for it. This may partly be due to the fact that researchers still aren't entirely sure what triggers endometriosis.
But one factor that might increase a woman's likelihood of developing endometriosis is their early life experiences. Recent research published by my colleagues and I has revealed a link between difficult childhood circumstances and a higher likelihood of being diagnosed with endometriosis .
Our study included all women born in Sweden between 1974 and 2001, totalling over a million women. We then followed them from birth using the Swedish register system, which allowed us to track each participants' health data.
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We also looked at different indicators of childhood adversity that had been captured through the registers. We focused specifically on experiences which previous studies have shown can lead to negative mental or physical health later in life.
This included having a parent with substance abuse problems , having had to spend a night in the care of child-protection services , having to move around a lot or being exposed to violence. In total, we included 11 indicators of childhood adversity in our analysis.
We then compared the likelihood of receiving an endometriosis diagnosis in women who had experienced each specific type of childhood adversity with women who had not. We controlled for factors that might have influenced the results, including the womens' ages, the year they were born, their county of birth and if they had been been smaller than average at birth.
Our results showed that having experienced some form of adversity between birth to 15 years of age was associated with a higher risk of being diagnosed with endometriosis later in life. The only adverse childhood event that wasn't linked with a greater risk of being diagnosed with endometriosis was familial death.
Women who had been exposed to violence had the highest risk increase, with an over twofold greater likelihood of being diagnosed with endometriosis compared with all other women.
The likelihood of being diagnosed with endometriosis increased the more adversity a woman had experienced in their childhood. Women who had experienced one type of adversity in childhood had a 20% greater likelihood of being diagnosed with endometriosis. But women who had experienced five or more types of adversity had a 60% greater likelihood.
We also ran a separate analysis that included women who experience painful periods (dysmenorrhea) to see if it affected the results. Many women who are diagnosed with endometriosis initially seek help from their doctor because they experience painful periods . We included women who had dysmenorrhea to capture women who might have endometriosis, but had not yet received a proper diagnosis. The results were similar even when we included women with dysmenorrhea in our analysis.
Previous studies which have looked at self-reported early childhood trauma have seen a link with endometriosis . But our study looked not only at remembered experiences of trauma, but also at other indicators of stress.
Endometriosis and immune function
Our findings may be explained, at least in part, by immune system processes and chronic inflammatory responses.
Having experienced adversity during childhood has previously been linked to higher levels of chronic inflammation, as well as an increased risk for autoimmune disorders . Greater levels of inflammation in the body could worsen endometriosis symptoms or even trigger endometriosis to develop.
Another possible way childhood adversity could affect endometriosis is through increased pain. Childhood adversity has been linked to a higher risk for chronic pain conditions . This could lead to women in our study who had gone through childhood adversity experiencing more painful symptoms on average, and therefore being more likely to seek medical help and receive a diagnosis.
Further research might dig into these possible mechanisms. This would improve our understanding of how and why the disease develops. A better understanding of the mechanisms behind the pain experienced by women with endometriosis might also allow researchers to develop more effective treatments than those currently available.
Our study reinforces the conclusions of previous studies which show a link between early childhood adversity and poor health in later life. This kind of research suggests a connection between mental and physical health, and indicates that we need to re-examine our view of the mind and body as separate entities.
It should be noted that our study is observational, which means it cannot prove that adverse events in childhood cause endometriosis, it can only show an association between the two things.
However, our study does highlight the importance of devoting resources to help parents and children. Helping families escape poverty, treating parental addiction or providing stable housing could lead to a healthier population in the future.
Marika Rostvall receives funding from Karolinska Institutet, Region Stockholm and Karolinska University Hospital.
