CHILDHOOD SEXUAL AND PHYSICAL ABUSE AND LATER TYPE 2 DIABETES

Child Abuse Linked to Increased Risk for Type 2 Diabetes in Adults CME

News Author: Caroline Cassels
CME Author: Désirée Lie, MD, MSEd

CME Released: 11/15/2010; Valid for credit through 11/15/2011

November 15, 2010 — Women who experience physical or sexual abuse as children or adolescents are at significantly increased risk of developing type 2 diabetes, a large, longitudinal cohort study suggests. Furthermore, investigators found there is a dose-response relationship such that the more severe the abuse, the greater the risk.

The latest findings from the Nurses' Health Study II show moderate or severe physical abuse was associated with a 26% to 54% higher risk for diabetes in adulthood. Unwanted sexual touching was associated with a 16% higher risk for the disease. Forced sexual activity before adulthood carried a 34% increased risk if it occurred once and but carried a 69% greater risk if it occurred more frequently.

"Although there was no evidence of a multiplicative, synergistic impact of experiencing both physical and sexual abuse, women who experienced both types of abuse had higher absolute risks of diabetes than expected from physical or sexual abuse alone.

"Girls who experience both types of abuse may suffer more severe abuse, more emotionally damaging abuse, or more chronic abuse than girls who experienced abuse of one type," the researchers, led by Janet Rich-Edwards, ScD, director of developmental epidemiology at the Conners Center for Women's Health, Brigham and Women's Hospital, Boston, Massachusetts, write.

The study was published online November 9 in the American Journal of Preventive Medicine.

According to investigators there is a considerable amount of research examining the psychological sequelae of childhood abuse but few studies examining lifelong physical consequences, with 1 exception.

The researchers note that there has been a consistently reported link between child abuse and adult obesity and evidence indicating that child abuse leads to overweight.

The study authors add that because obesity is a major risk factor for type 2 diabetes, it may be that early abuse may lead to the disease via this pathway. They also note that experimental and observational research suggests that "early trauma may cause lasting dysregulated stress responsivity, which may link child abuse with diabetes through physiologic pathways independent of adiposity."

According to investigators, earlier studies examining childhood trauma and diabetes have been limited by small sample sizes, cross-sectional design, unvalidated or nonspecific metabolic outcomes, or cursory assessments of abuse history.

To examine the extent to which child physical or sexual abuse is associated with type 2 diabetes, the researchers examined data from 67,853 women participating in the Nurses' Health Study II.

Established in 1989, the cohort has been followed by biennial mailed questionnaires asking about risk factors and disease incidence. In 2001 a Violence Questionnaire was sent to 91,297 study participants and 67,853 individuals responded. The investigators then examined reported lifetime abuse in 2001 and corresponding risk for diabetes from 1989 through 2005.

More than half (54%) of participants reported mild to severe physical abuse as a child or teen and 34% reported experiencing sexual abuse. Adjusted analyses revealed that compared with women who reported no physical abuse, the hazard ratios (HRs) were 1.03 (95% confidence interval [CI], 0.91 – 1.17) for mild physical abuse, 1.26 (95% CI, 1.14 – 1.40) for moderate physical abuse, and 1.54 (95% CI, 1.34 – 1.77) for severe physical abuse.

Compared with women who reported no childhood or adolescent sexual abuse, the HRs were 1.16 (95% CI, 1.05 – 1.29) for unwanted sexual touching, 1.34 (95% CI, 1.13 – 1.59) for a single episode of forced sexual activity, and 1.69 (95% CI, 1.45 – 1.97) for repeated forced sex.

"The more severe the reported abuse, the higher the woman's risk of developing type 2 diabetes as an adult," Dr. Rich-Edwards said in a statement.

The investigators report that adult body mass index accounted for 60% of the association of child and adolescent physical abuse and 64% of the association of sexual abuse with diabetes.

"Interpersonal violence is a prevalent and understudied threat to women's health," said Dr. Rich-Edwards. "Since child abuse predicts later obesity, and obesity is one of the primary causes of chronic disease, our study demonstrates just one of many potential health risks associated with childhood abuse."

The investigators note that there is a need for further investigation of potential associations between abuse of girls and women with health issues.

The study authors have disclosed no relevant financial relationships.

Am J Prev Med. Published online November 9, 2010.
Clinical Context

A total of 52% of US women have been physically assaulted, and 15% have been raped in their lifetime. There is evidence that links childhood abuse, but not childhood sexual abuse, to adult type 2 diabetes, mediated by an increased body mass index.

This is a longitudinal study within the Nurses' Health Study II to examine the association between childhood physical and sexual abuse and the risk for adult diabetes.
Study Highlights

* The Nurses' Health Study II is a cohort of 116,430 registered nurses aged 25 to 42 years in 1989 who were followed up by mailed biennial questionnaires.
* In 2001, a Violence Questionnaire was mailed to 91,297 participants; 68,376 participants returned their questionnaires.
* Participants contributed person-time from 1989 until their last returned questionnaire, diabetes diagnosis, or follow-up in 2005.
* All 2074 cases of women with type 2 diabetes were examined from 1989 to 2005.
* Excluded were women with baseline diabetes diagnosis and those with diabetes secondary to other treatments.
* Diabetes was confirmed with use of the responses to the biennial questionnaire.
* The Violence Questionnaire covered 3 periods: childhood up to age 11 years, adolescence aged 11 to 17 years, and adulthood.
* Childhood and adolescent physical abuse were assessed through an adaptation of the revised Conflict Tactics Scale.
* Physical abuse during childhood was categorized as no physical abuse; being "pushed, grabbed, or shoved" at any frequency; being "kicked, bitten, or punched once"; being "hit with something" once; or being subjected to any of these abuses more than once.
* Severe physical abuse included being choked or burned.
* Participants were categorized by the most severe violence event.
* Child and adolescent sexual abuse were measured by questions regarding unwanted sexual touching and forced sexual activity.
* Exposure was classified as no sexual abuse, unwanted sexual touching only, forced sexual activity once, and forced sexual activity more than once.
* Covariates considered included race/ethnicity, birth weight and family history of type 2 diabetes, childhood adiposity, depression, and school diet.
* 54% of participants reported physical abuse in childhood or adolescence, including 9% who reported severe physical abuse.
* One third (34%) reported sexual abuse in childhood or adolescence, including 12% with forced sexual activity, half of whom reported this happening more than once.
* There was a dose-response association between physical abuse and the risk for type 2 diabetes; adjustment for covariates attenuated the association.
* Adjusted analyses revealed that compared with women who reported no physical abuse, the HRs were 1.03 (95% CI, 0.91 - 1.17) for mild physical abuse, 1.26 (95% CI, 1.14 - 1.40) for moderate physical abuse, and 1.54 (95% CI, 1.34 - 1.77) for severe physical abuse.
* Mild physical abuse in childhood was not associated with adult type 2 diabetes, but moderate and severe physical abuse were associated with a 26% and 54% higher risk for diabetes, respectively.
* Physical and sexual abuse history were correlated (P < .0001).
* Moderate and severe physical abuse predicted an increased risk for type 2 diabetes, whether women had experienced sexual abuse.
* Women who experienced unwanted sexual touching had a 16% increased risk for adult type 2 diabetes.
* Women who had experienced forced sexual abuse once vs repeatedly had a 34% to 69% high risk for adult type 2 diabetes vs women who experienced no sexual abuse.
* The HRs were 1.16 (95% CI, 1.05 - 1.29) for unwanted sexual touching, 1.34 (95% CI, 1.13 - 1.59) for a single episode of forced sexual activity, and 1.69 (95% CI, 1.45 - 1.97) for repeated forced sex.
* Most girls had experienced both physical and sexual abuse.
* Among girls who experienced sexual but not physical abuse, the risk for type 2 diabetes was 56% higher.
* Physical and sexual abuse interacted on an additive, but not multiplicative, scale indicating that the absolute, but not relative, risk for type 2 diabetes was higher among women who had experienced both forms of abuse.
* There was a 29% increased risk for type 2 diabetes for moderate physical abuse and a 49% increased risk for severe physical abuse isolated to childhood or adolescence.
* For isolated sexual abuse, there was a 19% increased risk for sexual touching, 32% for forced sex once, and 86% for repeated forced sex.
* Adult body mass index accounted for 60% of the association for physical abuse and 64% of the association for sexual abuse with the risk for adult diabetes.
* The authors concluded that childhood physical and sexual abuse both correlated positively with the risk for adult type 2 diabetes and that more than 60% of this effect was mediated through increased body mass index. Also, between 10% and 30% of the effect was accounted by the abuse itself.
* The estimated proportion of women with type 2 diabetes attributed to childhood physical or sexual abuse is 9%.

Clinical Implications

* There is a dose-response association between childhood and adolescent physical abuse and the risk for adult type 2 diabetes; this effect is partly mediated by increased body mass index.
* There is a dose-response association between childhood and adolescent sexual abuse and the risk for adult type 2 diabetes; this effect is partly mediated by increased body mass index.