Susan Jeffrey

November 15, 2011

November 15, 2011 (Orlando, Florida) — Women who suffer either physical or sexual abuse early in life have a significantly increased risk for subsequent cardiovascular events, including myocardial infarction and stroke, a new study suggests.

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 greater than 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.

Dr. Janet Rich-Edwards

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 Janet Rich-Edwards, ScD, MPH, associate professor in the Department of Medicine at Brigham and Women's Hospital in Boston, Massachusetts, 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," Dr. Rich-Edwards concluded.

The results were presented here at the American Heart Association (AHA) 2011 Scientific Sessions.

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 to 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," Dr. Rich-Edwards said.

"I have to say that no matter how many times I see this, the data shock me every time."

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 years, "so this is an exposure of girls and adolescent women."

There are 2 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 for coronary heart disease of 50% for physical abuse and 40% for sexual abuse. The other, the National Comorbidity Survey of 4251 women, showed divergent findings for physical and sexual abuse, with no increased risk for coronary heart disease for those reporting physical abuse, but a 5-fold increased risk for those with a history of sexual abuse.

"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," Dr. Rich-Edwards noted.

Her report used data from the Nurses' Health Study II, which 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 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 who had a history of cancer, myocardial infarction, or stroke before baseline, the study group included 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 the woman was a child or teenager.

Physical abuse, classified as mild, moderate, or severe, 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 years.

They found that 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 5 years, and parental education, Dr. 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% confidence interval, 24% - 71%) of the association between severe physical abuse and adult cardiovascular disease is explained by these established cardiovascular risk factors."

Table 1. Risk for Cardiovascular Events With Physical Abuse vs No Abuse

Analysis Mild Physical Abuse Moderate Physical Abuse Severe Physical Abuse
Hazard ratio (95% confidence interval) 0.91 1.02 1.46
Hazard ratio (95% confidence interval), adjusted for cardiovascular risk factors 0.88 0.95 1.23

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

When the researchers 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% confidence interval, 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," Dr. Rich-Edwards noted.

Table 2. Risk for Cardiovascular Events With Sexual Abuse vs No Abuse

Analysis Sexual Touching Forced Sexual Activity
Hazard ratio (95% confidence interval) 1.10 1.56
Hazard ratio (95% confidence interval), adjusted for cardiovascular risk ractors 1.05 1.34

Additional analyses showed that the associations were stronger for women without adult abuse, and for stroke than for myocardial infarction. 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 < .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," Dr. Rich-Edwards concluded.

About 40% of the increased risk appears to stem from lifestyle risk factors, so 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 is important that physicians talk about the issue, and let women know that, "though 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 like stress reactivity, for example, which appears heightened in women with a history of abuse, are just beginning to be investigated now.

Findings "Disturbing"

Dr. Donna K. Arnett

Asked for comment on these findings, Donna K. Arnett, PhD, professor and chair of epidemiology at the University of Alabama, Birmingham, and 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," Dr. Arnett told Medscape Medical News.

"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 did not 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 authors and Dr. Arnett have disclosed no relevant financial relationships.

American Heart Association (AHA) 2011 Scientific Sessions: Abstract 16865. Presented November 14, 2011.


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