Does shift work increase the levels of blood pressure and cholesterol among hospital nurses? A historical cohort study

 Introduction: Controversies exist in publications about the association between shift work and hypertension. This study aimed to explore the relationship between shift work and the level of systolic and diastolic blood pressure as well as serum cholesterol among nurses in Kerman province, Southeast, Iran.   Materials and Methods : In this historical cohort study 100 hospital nurses who had been employed for more than five years were recruited. Respondents were divided into two groups based on their working schedule (shift work/day work). After one year follow up, both systolic and diastolic blood pressures were measured. A blood sample was also taken for recording the level of serum cholesterol. Data were analysed using SPSS (version 14) and paired t-test and Mann Whitney U test and relative risk with 95% CI was also calculated.  Results: Demographic variables as well as the mean working years between shift working (10.98±3.6yrs) and day working (11.18±4.4yrs) nurses were not significantly different. The results of age-adjusted relative risk calculation showed that even after adjusting for respondents’ age, there was not any significant risk of suffering from higher blood pressure among shift workers. The mean levels of cholesterol in the serum of shift workers (192.18± 43.6) and day workers (186.7 ±47.7) were not significantly different. Conclusions: Our findings confirmed the previous studies’ results that reported no significant association between shift working and the level of blood pressure among nurses. More investigations are needed to explore factors, which could increase the risk of hypertension and cardiovascular diseases among shift working nurses.