Childhood Sexual Abuse Linked to Higher Cancer Risk in Older Adults, Study Finds

Childhood sexual abuse involving threats, force, or physical harm is linked to a significantly higher risk of cancer in later life, according to a new study of older Canadian adults. Researchers found that survivors of this severe form of childhood sexual violence were almost twice as likely to report a cancer diagnosis decades later compared to those without such experiences.

The study analyzed data from 2,636 Canadians aged 65 and older who participated in a nationwide survey on mental health and access to care. Among participants, 21 percent reported a cancer diagnosis overall. However, the rate was notably higher for those who experienced specific types of childhood adversity: 27 percent of those exposed to parental domestic violence, 28 percent of those who suffered physical abuse, and 35.5 percent of those who endured childhood sexual violence involving coercion, threats, restraint, or physical harm reported a cancer diagnosis.

To determine whether adult behaviors and habits could explain the increased cancer risk, researchers adjusted their analysis for numerous factors known to influence cancer development. These included sex, race, immigrant status, marital status, education, income, smoking status, physical activity, alcohol and drug problems, chronic pain, social support, spirituality, and other chronic health conditions. Despite accounting for these variables, the association between severe childhood sexual abuse and cancer remained largely unchanged.

“We know that people who have experienced childhood abuse are more likely to leave school earlier, have lower income in adulthood, smoke, and struggle with alcohol or drugs,” said Esme Fuller-Thomson, PhD, professor and director of the Institute for Life Course and Aging at the University of Toronto and senior author of the study. “Because those factors are linked to higher cancer risk, it seemed reasonable that they might help explain the connection between childhood sexual abuse and cancer in later life. However, when we accounted for all of these factors in our analyses, they did not explain the association. The link between childhood sexual abuse and cancer looked very similar before and after. That suggests these adult factors are not the main explanation for what we are seeing.”

The researchers emphasized that while the study cannot prove causation due to its observational design, the findings align with a growing body of research on how severe early trauma may become biologically embedded over time. Chronic exposure to adversity during childhood can lead to toxic stress, which disrupts normal brain development and keeps the body’s stress response system in a persistent state of high alert. This prolonged activation may impair gene expression, brain function, immune function, and inflammatory responses, potentially contributing to long-term health risks.

“Adults who were abused as children often have higher levels of chronic inflammation years later,” Fuller-Thomson explained. “Long-term changes in stress hormones, immune function, and inflammatory responses could help explain why severe trauma is connected to poorer health decades later.” She noted that while links to conditions like heart disease, stroke, arthritis, asthma, COPD, diabetes, depression, and disability have been consistently observed in prior research, the connection to specific cancer types remains less understood.

The study has several limitations, including reliance on self-reported cancer diagnoses and retrospective reports of childhood adversity. It did not examine specific cancer types or account for every potential influencing factor, such as body mass index, genetic predisposition, childhood poverty, or more detailed characteristics of the abuse itself.

Despite these constraints, the findings underscore the importance of considering trauma history in long-term health assessments. “Most survivors of childhood abuse don’t get cancer — this research is about risk, not destiny,” Fuller-Thomson said. However, understanding a patient’s trauma history can inform more supportive and responsive care, particularly in cancer prevention and treatment settings.

Katie Ports, PhD, principal researcher at the American Institutes for Research (AIR), who was not involved in the study, highlighted the broader implications: “Childhood experiences, positive and negative, lay the foundation for subsequent health and well-being. If we care about adult health outcomes, we also must care about childhood. Preventing adverse childhood experiences such as child sexual abuse and promoting positive experiences is everyone’s responsibility.”