Data collection:
On daily basis staff reviewed medical records and interviewed recruited AMI patients using a structured interviewer-administered questionnaire to record sociodemographic data, self-reported history of recent respiratory symptoms including fever, cough, sore throat, runny nose and difficulty breathing within past week of AMI onset, information on lifestyle and co-morbid illness and conducted clinical examination as well as anthropometric measurements of the participants. The blood cardiac troponin results were obtained from hospital records measured at baseline in nanograms per millilitre (ng/mL).