Conceptual framework
The conceptual framework was described in most studies. Four studies employed multiple models to guide intervention development . Among all studies, the health belief model (HBM) was the most commonly used. HBM includes six main constructs that explain one's attitude and perceptions in relation to health behaviour. These constructs are perceived susceptibility to the disease and its severity once contracted, perceived benefits of and perceived barriers to action, cues-to-action and self-efficacy in engaging health behaviour