Risk and Protective Factors for Intimate Partner Violence Against Women: Systematic Review and Meta-analyses of Prospective-Longitudinal Studies.

BACKGROUND: The estimated lifetime prevalence of physical or sexual intimate partner violence (IPV) is 30% among women worldwide. Understanding risk and protective factors is essential for designing effective prevention strategies.
OBJECTIVES: To quantify the associations between prospective-longitudinal risk and protective factors and IPV and identify evidence gaps. SEARCH
METHODS: We conducted systematic searches in 16 databases including MEDLINE and PsycINFO from inception to June 2016. The study protocol is registered with PROSPERO (CRD42016039213). SELECTION CRITERIA: We included published and unpublished studies available in English that prospectively analyzed any risk or protective factor(s) for self-reported IPV victimization among women and controlled for at least 1 other variable. DATA COLLECTION AND ANALYSIS: Three reviewers were involved in study screening. One reviewer extracted estimates of association and study characteristics from each study and 2 reviewers independently checked a random subset of extractions. We assessed study quality with the Cambridge Quality Checklists. When studies investigated the same risk or protective factor using similar measures, we computed pooled odds ratios (ORs) by using random-effects meta-analyses. We summarized heterogeneity with I2 and τ2. We synthesized all estimates of association, including those not meta-analyzed, by using harvest plots to illustrate evidence gaps and trends toward negative or positive associations. MAIN
RESULTS: Of 18 608 studies identified, 60 were included and 35 meta-analyzed. Most studies were based in the United States. The strongest evidence for modifiable risk factors for IPV against women were unplanned pregnancy (OR = 1.66; 95% confidence interval [CI] = 1.20, 1.31) and having parents with less than a high-school education (OR = 1.55; 95% CI = 1.10, 2.17). Being older (OR = 0.96; 95% CI = 0.93, 0.98) or married (OR = 0.93; 95% CI = 0.87, 0.99) were protective.
CONCLUSIONS: To our knowledge, this is the first systematic, meta-analytic review of all risk and protective factors for IPV against women without location, time, or publication restrictions. Unplanned pregnancy and having parents with less than a high-school education, which may indicate lower socioeconomic status, were shown to be risk factors, and being older or married were protective. However, no prospective-longitudinal study investigated the associations between IPV against women and any community or structural factor outside the United States, and more studies investigated risk factors related to women as opposed to their partners. Public health implications. This review highlights that prospective evidence for perpetrator- and context-related risk and protective factors for women's experiences of IPV outside of the United States is lacking and urgently needed to inform global policy recommendations. The current evidence base of prospective studies suggests that, at least in the United States, education and sexual health interventions may be effective targets for preventing IPV against women, with young, unmarried women at greatest risk.