ARYA Atheroscler9520130918A retrospective cohort study on factors associated blood pressure using multilevel modeling293299ENMohammadGholami-FesharakiAnoshirvanKazemnejadProfessor, Department of Biostatistics, School of Medical Sciences, Tarbiat Modares University, Tehran, Iran. kazem_an@modares.ac.irFaridZayeriJavadSanatiHamedAkbari201302062013041520130315BACKGROUND: Hypertension is a health problem in Iran. Given the importance of this subject, we reviewed the factors affecting the blood pressure in this survey. METHODS: This retrospective cohort study was performed on 3961 male workers employed at Isfahan Polyacryl Corporation (Iran) in health and safety executive between 1996 until 2008. In this study, systolic and diastolic blood pressure (SBP and DBP) were considered as dependent variables; body mass index (BMI), age, type of job, marital status, shift work and educational level were considered as independent variables. MLwiN programmer version 2.1 was used to analyze the data. RESULTS: BMI, age, shift work, marital status and educational level had statistical significant association with DBP. The result for SBP was similar to DBP except shift work and educational level that had no statistically significant association. CONCLUSION: The results can be considered in the industry to provide practical solutions to reduce blood pressure.   Keywords: Blood Pressure, Cohort Study, Retrospective Study, Risk Factor, Multilevel Anal