Contrary to common perception, households with a single parent and no other adults had no increased risk of fatal injury.
In this study of young children who died from inflicted injuries, 21 percent lived in homes with an unrelated adult, compared to only one percent of controls. More than 80 percent of those households consisted of the child's mother and her boyfriend. In 74 percent of those cases, the boyfriend was the perpetrator.
"It is not single parenthood per se that puts a child at risk," said Bernard Ewigman, M.D., M.S.P.H., professor and chairman of family medicine at the University of Chicago. "It is the presence in the household of unrelated adults, usually a male boyfriend, that dramatically increases the risk.
"At the same time, we need to use caution in interpreting these findings," Ewigman said. "Most unrelated adults living in a household with young children do not injure them."
The study, "Child Deaths Resulting from Inflicted Injuries: Household Risk Factors and Perpetrator Characteristics," by Ewigman and Patricia Schnitzer, Ph.D., research assistant professor of family and community medicine at the University of Missouri-Columbia, used data from the Missouri Child Fatality Review Program, developed by Ewigman in 1991, to examine all 149 children under the age of five who died from injuries inflicted by a parent or caregiver in Missouri between January 1, 1992, and December 31, 1999.
They compared their results with 298 randomly selected Missouri households in which a young child of similar age had died, but of natural causes.
Most of the deaths involved very young children; 56 percent were less than one year old and 90 percent were less than three. Seventy-three percent of the fatal injuries were caused by shaking or striking the child.
Children who died from inflicted injuries were more likely than controls to be born to young, unmarried women with less than a high school education and limited income. They were more than twice as likely to have siblings under age five and to live in households previously reported for abuse or neglect.
In this study, the researchers focused on household composition as an independent risk factor for fatal inflicted injuries. They classified households into five groups, those with:
1. Two biologic parents (cases - 37%, controls - 64%),
2. One biologic parent and no other adult (cases - 28%, controls - 30%),
3. Two biologic parents and another related adult (cases - 10%, controls - 3%),
4. Step or foster parents (cases - 4%, controls - 2%),
5. One or two biologic parents and another unrelated adult (cases - 21%, controls - 1%).
They found that comparatively few of the injured children lived with both biologic parents. While 72 percent of US children live in two-parent households, only 37 percent of fatal inflicted injuries came from such a household. Risk was just as low in households with a single parent and no other adults.
The risk doubled when there was a related adult who was not a parent living in the home. It increased nearly 50-fold, however, when there were unrelated adults living there.
The perpetrator was identified for 132 (89%) of the 149 cases. Most (71%) were male. Forty-six (35%) were the child's father, 32 (24%) were the mother's boyfriend. In 26 cases (20%) the mother caused the injury.
"This disproves the common misconception that children in single-parent households are more likely to die from inflicted injury," Schnitzer said. "It is less the mother's inability to control her temper than her lack of access to adequate child care.
"Many single mothers have to work and can't afford child care, so they leave a child in the care of a man -- often with a limited child care experience and emotional commitment to the child -- who then inflicts injury, often out of frustration" Schnitzer said.
The authors suggest that subsidized child care, visits by nurses to high-risk homes, and instructional programs could reduce the risk of inflicted injury by supporting single mothers as well as preparing males -- biologic fathers as well as other male caregivers -- to help with child care. Education about shaken baby syndrome, they said, should be offered to both male and female caregivers.
Of all 50 states, according to the National Women's Law Center, Missouri ranks last in providing subsidies for child care to low-income families.
The National Institute for Child Health and Human Development funded this study.