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).