Noll's research on childhood sex abuse featured on CBS News
By Shanika Gunaratna, CBS News
For countless victims, the experience of sexual abuse during the formative years of childhood never fades away. Studies show that such abuse casts a shadow over children’s physical and mental health for decades, increasing an individual’s risk of anxiety and depression, eating disorders, self-inflicted harm, violence, and more.
Now, researchers who’ve carefully tracked a small cohort of child sex abuse survivors over three decades say they’ve observed another phenomenon: that child sex abuse accelerates the timeline of puberty in adolescent girls. The Pennsylvania State University researchers shared their findings in the Journal of Adolescent Health.
How could sex abuse possibly change a child’s physical development?
In non-abused children, physical, developmental and psychosocial development tend to occur on a similar timeline — meaning that children generally develop the psychological capacity to navigate the changes that happen their bodies during puberty.
But high-stress experiences like sexual abuse disrupt those developmental timelines, the Penn State researchers said. The abuse can trigger increased levels of stress hormones; specifically, the stress can lead to heightened activity in the “hypothalamic–pituitary–adrenal” (HPA) axis, which can then jump-start puberty ahead of schedule, the researchers said.
“At some point, the body can’t regulate stress hormones efficiently,” lead researcher Jennie Noll told CBS News. Noll, a professor at Penn State, teaches human development and family studies.
Early puberty can have long-term health consequences. It’s been linked to a higher risk of certain cancers, like ovarian and breast cancer, due to prolonged exposure to estrogen. Early puberty is also associated with higher rates of depression, substance abuse, fertility problems, sexual risk-taking, and teenage pregnancy. Researchers say girls who develop early can face sexual expectations they aren’t emotionally prepared to navigate.
The study, which began in 1987, tracked a sample of 80 girls who had experienced sexual abuse and were referred by child protective services. Working closely with nurses and protective services, researchers amassed data about the group over a span of 30 years.
The girls in the sample had all experienced abuse at the hands of family members, and the average length of that abuse was two years. The cases were “not atypical of a lot of sexual abuse that we see reported to protective service agencies around the country,” Noll said.
The girls were tracked from pre-puberty to full maturity. Researchers leaned on a system called Tanner staging, which doctors use to track breast and pubic hair growth as markers for girls’ development. Noll called it the “gold standard” to measure puberty.
The findings were stark: girls who had experienced sexual abuse in childhood were eight months earlier in breast development and 12 months early in pubic hair growth. Those results held steady when researchers controlled for a range of risk factors associated with abuse, such as the absence of a biological father, obesity, and poverty.
Ryan Fields, associate director at Johns Hopkins University’s Moore Center for the Prevention of Child Sexual Abuse, called the research “fascinating.”
“This study joins the body of research that really shows how experiencing child sexual abuse increases one’s risk for mental health and behavioral health problems across the life course — beyond the immediate pain or injury associated with the event,” said Fields, who was not involved in the study.
Other researchers first noted the link between child sex abuse and earlier puberty in 1988. But the Penn State researchers say this study is the most conclusive and precise look at the subject to date, thanks in part to their use of the Tanner framework for measuring puberty.
It’s difficult to establish how many children suffer sexual abuse, but research by the Crimes Against Children Research Center estimates 1 in 5 girls are victimized at some point, as are 1 in 20 boys. That research suggests children are most vulnerable to sexual abuse between the ages of 7 and 13. In 2009, the World Health Organization identified child sex abuse as one of the leading preventable risk factors that contribute to the worldwide burden of disease.
“Many argue that this is one of the most stressful conditions a child can endure in our society — in a non-war-torn society,” Noll said.
But survivors of child sexual abuse often demonstrate deep resilience over the course of their lives.
“The resilience of survivors of child sexual abuse can’t get lost,” Fields said. “Many youth who experience child sexual abuse fully recover from that experience.”
The study is continuing; the researchers will continue to monitor the group of women as they age, paying particular attention to cancer rates over time.
For Noll, the 30-year study demonstrates what can happen when academics partner closely with those on the front lines, like nurses and child welfare workers. One of their goals is to develop laws that are more attuned to how sexual abuse actually reverberates in victims’ lives in the long term.
“We want to... [provide] actual empirical data to point to that shows that when child abuse sexual abuse is not prevented and treated, these children are much worse off down the road — both psychosocially and physically.”
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