Cumulative effect of risk and protective factors on unintentional injury for Chinese rural children: a nested case-control study

BACKGROUND: Childhood unintentional injuries are the leading cause of death and disability for children. Despite the risk factors that lead to the occurrence of injuries have been identified, the relationship between cumulative effect of risk/protective factors and unintentional injuries is unclear. The aim of this study was to explore the cumulative effect of risk factors as well as protective factors and their interaction on unintentional injury to rural children. METHODS: We used a nested case-control study design from a cohort database. The study comprised 1696 children aged 6 to 14 years. Among them, 424 were cases with unintentional injury and 1272 were their matched control. After controlling for the significant sociodemographic variables, linear and logistic regression analyses were performed. RESULTS: The risk of unintentional injury increased with the increasing number of risk factors - RFI from 1 to 3 (OR(RFI(1)) = 0.978, 95% CI 0.739–1.296), (OR(RFI(2)) = 1.720, 95% CI 1.233–2.397), (OR(RFI(3)) = 5.162, 95% CI 3.129–8.517). PFI (1) was associated with lower risk of injury, but this association was at the edge of significance (p = 0.052). The increased risk in those with PFI (2) was not significant (p = 0.254). The severity of the unintentional injury significantly increased with the increasing number of the risk factors (p < 0.01), and significantly decreased with both the increasing number of protective factors (p = 0.001) and interaction of the risk and protective factors (p < 0.01).The interaction of RFI and PFI could explain 32.2% of the unintentional injury severity. CONCLUSIONS: According to the findings of the present study, cumulative risk factors and protective factors, as well as their interaction were associated with the occurrence and/ or severity of unintentional injury in children. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12889-021-11769-7.