Nov 17, 2011  Susan Jeffrey

Adapted from Medscape Medical News—a professional news service of WebMD

Orlando, FL - Women who suffer physical or sexual abuse early in life have a significantly increased risk for subsequent cardiovascular events, including MI and stroke, a new study suggests [1]. The study was presented Monday at the American Heart Association 2011 Scientific Sessions.

The study, using data from the Nurses' Health Study II, shows that women who reported they had experienced forced sexual activity during childhood or adolescence had a >50% increased risk for cardiovascular disease. The relationship with physical abuse was significant but less robust, the authors note, and will have to be confirmed in other data sets.

This is the third study to show that forced sex among girls is linked with at least a 50% increase in cardiovascular-event risk, lead author Dr Janet Rich-Edwards (Brigham and Women's Hospital, Boston, MA) said at a press conference here. The relationship was only partially explained by traditional cardiovascular risk factors.

"The consistency of the sexual-abuse studies suggests that we continue our abuse-prevention efforts in childhood and that we also develop specific cardiovascular disease prevention strategies tailored to the needs of women who've experienced abuse in childhood," Rich-Edwards concluded.

Increased risk

A national survey of 8000 women conducted by the National Institute of Justice and the Centers for Disease Control and Prevention in 1995-1996 showed that 52% of women "were willing to report to a stranger on the telephone that they had been physically assaulted during their lives, and 18% reported completed or attempted rape," Rich-Edwards said. "I have to say that no matter how many times I see this, the data shock me every time."

Dr Janet Rich-Edward

Most attacks took place in childhood, with 54% of those who reported a rape, or 9% of the overall group, reporting that the assault occurred before the age of 18, "so this is an exposure of girls and adolescent women."

There are two other studies in the literature looking at cardiovascular outcomes after physical or sexual abuse, she noted. One, the Adverse Childhood Experience Study of 17 000 men and women, found an increased risk of coronary heart disease of 50% for physical abuse and 40% for sexual abuse [1]. The other, the National Comorbidity Survey of 4251 women, showed divergent findings for physical and sexual abuse, with no increased risk of coronary heart disease for those reporting physical abuse, but a fivefold increased risk for those with a history of sexual abuse [2].

"Both of these studies are considerably smaller than the study I'm going to show you today and much less rigorous in terms of defining coronary heart disease and stroke," Rich-Edwards noted.

The Nurses' Health Study II includes 116 640 female registered nurses from 14 US states, who were aged 25 to 42 years at baseline in 1989. "At the end of follow-up for this particular analysis in 2007, they were age 43 to 60—so take note, these are very early cardiovascular events for women," she said.

The study's biennial questionnaire in 2001 asked women about their life experience with violence. "This allows us to look at events prospectively after they reported the violence to us and retrospectively from the beginning of the study until 2001 when we asked the questions."

For both time periods, cardiovascular events were validated by medical records. Self-reported unvalidated events were also included; both previous studies used only self-reported events. After excluding those who did not return the violence questionnaire or had a history of cancer, MI, or stroke prior to baseline, the study group comprised 67 315 women free of cardiovascular disease or cancer.

Child abuse was assessed using the Conflict Tactics Scale, a questionnaire that assesses levels of exposure. Spanking for discipline was not included as abuse. Physical abuse was classified as mild, moderate, or severe, depending on responses, and sexual abuse was classified as unwanted sexual touching or forced sexual activity while they were a child or teenager.

Physical abuse was reported by 54% of the cohort, and 9% reported severe physical abuse, the researchers report. Sexual abuse was reported by 33% of the women, and 11% reported forced sexual activity before age 18.

They found mild or moderate physical abuse in childhood and adolescence was not associated with cardiovascular disease, but a 46% increase in risk was seen in those with a history of severe physical abuse, after adjustment for age, race, parental cardiovascular history, body type of the girl at age five, and parental education, Rich-Edwards noted.

After further adjustment for risk factors in adulthood that are likely themselves to be linked to a history of abuse, including smoking, alcohol use, body-mass index, diabetes, and hypertension—the association between physical abuse and cardiovascular events was "dampened," she noted. "In fact, 47% (95% CI 24%-71%) of the association between severe physical abuse and adult cardiovascular disease is explained by these established cardiovascular risk factors."

Risk for cardiovascular events with physical abuse vs no abuse

Physical abuse

Mild

Hazard ratio (95% C)

0.91

Hazard ratio (95% C), adjusted for CV risk factors

 0.88

 Moderate

Hazard ratio (95% C)

1.02

Hazard ratio (95% C), adjusted for CV risk factors  

 0.95

 Severe

 Hazard ratio (95% C)

 1.46

Hazard ratio (95% C), adjusted for CV risk factors  

 1.23

The relationship with sexual abuse was stronger. Women with a history of forced sexual activity had a 56% increase in risk of cardiovascular events; there was no increased risk seen with sexual touching only.

When they again adjusted for cardiovascular risk factors in adulthood, the relationship was again mitigated, but not as much as with physical abuse; these risk factors accounted for about 38% of the excess risk (95% CI 25%-53%).

"So just shy of 40% of the association between forced sex in childhood and cardiovascular disease in adulthood is explained by established risk factors, which is a lot left unexplained," Rich-Edwards noted.

Risk for cardiovascular events with sexual abuse vs no abuse

Sexual abuse

 Sexual touching

Hazard ratio (95% C)

 1.10

Hazard ratio (95% C), adjusted for CV risk factors

 1.05

 Forced sexual activity

 1.56

 1.34

Simultaneous adjustment for both sexual and physical abuse again dampened both associations "modestly," the researchers note.

There was also a relationship between case-confirmation and risk for cardiovascular events, with the lowest risk seen in the "definite" confirmed cases of physical and sexual abuse, although the association with forced sex was still statistically significant. When they included definite, probable, and unconfirmed cases of physical and sexual abuse, hazard ratios increased to 1.77 for physical abuse and 2.06 for forced sex (p<0.05 for both).

"I think what this points to is, first and foremost, the need for prevention; not only the prevention of child abuse, but in pediatrics offices and other agencies that spot child abuse, understanding that it's not just a short-term problem, but there's really a long tail of chronic disease that ensues from this," Rich-Edwards concluded.

About 40% of the increased risk appears to stem from lifestyle risk factors, and those events might be prevented "just by applying what we know."

In the adult primary-care setting, where these women will most probably first be seen, it's important that physicians talk about the issue and let women know that, "although they may have had their bodies disrespected as children, there's a lot they can do as adults to take good care of themselves," she said. Tailored approaches for these women taking into account their experiences might also be developed.

"Finally, the fact that we can explain only about half of it through our known pathways means we have a lot more work to do in terms of understanding the other ways in which this early psychosocial stress is literally embodied," she concluded. Factors such as stress reactivity, for example, which appears heightened in women with a history of abuse, are just beginning to be investigated now.  

Findings "disturbing" 

Asked for comment on these findings, Dr Donna K Arnett (University of Alabama, Birmingham), president-elect of the American Heart Association, called these results "disturbing on a number of levels."

"First, the prevalence of abuse is much higher than many of us realize, and that it's associated with these other cardiovascular risk factors and other cardiovascular disease in later life provides a compelling case that we need to address this early in childhood," Arnett said.

"We need to screen for it, we need to understand it, and we need to intervene at the cause, which is this physical or sexual abuse in children, so that we prevent downstream cardiovascular disease."

Interestingly, known cardiovascular disease risk factors didn't entirely account for the increased risk, particularly for the sexual abuse, she noted, "and that's one that gets underreported, because it's often unseen."

The complete contents of Medscape Medical News, a professional news service of WebMD, can be found at www.medscape.com, a website for medical professionals.

Sources

Dong M, Giles WH, Felitti VJ, et al. Insights into causal pathways for ischemic heart disease: Adverse Childhood Experiences Study. Circulation 2004; 110:1761-1766.  

Goodwin RD, Stein MB. Association between childhood trauma and physical disorders among adults in the United States. Psychol Med 2004; 34:509-520. 

Related link

Stress in childhood boosts heart disease risk later in life

[heartwire > News; Sep 20, 2004]

http://www.theheart.org/article/159767.do