A randomized controlled trial to evaluate the impact of a geo-specific poster compared to a general poster for effecting change in perceived threat and intention to avoid drowning ‘hotspots’ among children of migrant workers: evidence from Ningbo, China

BACKGROUND Drowning among children of migrant workers is a major, though neglected public health issue in China. METHODS A randomised controlled trial was used to examine the potential impact of viewing a preventive health poster with/without geo-located drowning events on perceptions of drowning risk among Chinese migrant children. A total of 752 children from three schools in Jiangbei district were selected by multi-stage sampling and randomly assigned to the intervention (n = 380) or control (n = 372). Multilevel models were used to analyse changes in responses to the following questions after viewing the assigned poster for 10 min: (1) "Do you believe that drowning is a serious health problem in Ningbo city?"; (2) "Do you believe that there are lots of drowning-risk waters around you?"; (3) "Do you believe that the likelihood of your accessing a drowning-risk water is great?"; and (4) "Would you intend to avoid accessing to those drowning-risk waters when being exposed?" RESULTS At baseline there were no significant differences between the intervention and control groups in perceptions of drowning risk or covariates. Following the intervention, participants that viewed the geo-specific poster were more likely to respond more favourably to the first three questions (p < 0.001) than those who viewed the standard poster. However, there was no substantive difference between the geo-specific or standard poster in terms of changing intentions to avoid drowning hotspots (p = 0.214). CONCLUSIONS Use of 'geo-located' information added value to the effectiveness of a drowning prevention poster for enhancing awareness of drowning hotspots among children of migrant workers. TRIAL REGISTRATION Chinese Clinical Trial Registry ChiCTR-IOR-16008979 (Retrospectively registered) (The date of trial registration: Aug 5, 2016, the date of enrolment of the first participant: Nov 10, 2015).