Intergenerational continuity of child physical abuse: how good is the evidence?

BACKGROUND: There is widespread belief that individuals who were physically abused during childhood are more likely to abuse their own children than those who were not abused, but the empirical studies examining this belief have not been systematically reviewed. The aim of this study was to evaluate systematically, based on eight methodological standards derived from a hypothetical randomised controlled trial, the design of studies investigating the intergenerational transmission of child physical abuse. METHODS: We reviewed studies published between 1965 and 2000 in English that provided information about physical maltreatment in two generations and included a comparison group. Two investigators independently assessed whether each study met the methodological standards. FINDINGS: In the ten studies identified (four cohort, one cross-sectional, and five case-control), the relative risks of maltreatment in the children of parents who were abused during childhood were significantly increased in four studies (relative risks 4.75-37.8), but in three other studies the relative risks were less than 2. Most study reports provided a clear description of abuse of parents during childhood and abuse of their children. Five studies failed to avoid recall and detection bias; five did not ensure that controls were not themselves maltreated; eight did not provide adequate follow-up; and in six the report did not state whether the enrolled parent was responsible for the maltreatment. Most studies did not control for intervening factors, such as sociodemographic characteristics during the time of abuse of the parent generation and at the time their children were abused. Only one study met all eight criteria (relative risk of abuse transmission 12.6 95% CI 1.82-87.2) and one met six (1.05 0.53-2.06). INTERPRETATION: The one study that met all eight methodological standards provided evidence for the intergenerational continuity of child physical abuse, but that which met six standards did not support the hypothesis. Use of our model and methodological standards should improve the scientific quality of studies examining the effects of risk factors for adverse outcomes that may continue across generations.