Association between shift work and cardiovascular disease risk factors among healthcare workers of teaching hospitals of Mashhad University of medical sciences

Introduction: The studies about the effect of shift work on cardiovascular diseases (CVD) have inconsistent results. This study was conducted to assess the relationship between shift work and the CVD risk factors. Methods: A cross-sectional study was carried out during 1393-94. The participants were divided into two groups: shift workers (work shift between 3 pm and 7 am) and day workers. The shift workers were selected from among the Healthcare workers of 4 teaching hospitals of Mashhad and the day workers also were selected among the office workers by simple sampling. Demographic data, smoking, regular exercise, medical and occupational history were collected through a check list and interviews. Physical examination was done by a physician. Blood cholesterol, triglyceride and glucose were measured in a blood sample after standard fasting time. Results: A total of 439 subjects including 218 women and 221 men with a mean age of 34.6 years old participated in this study. In terms of work schedule, 229 participants (52) were day workers and 210 subjects (48) were shift workers. The effect of covariates such as age, employment duration and regular exercise was controlled statistically. Of all factors studied, diastolic blood pressure ≥ 90 mmhg and blood triglyceride level ≥ 150 mg/dl were associated with shift working.(p≤ 0.001). Conclusion: shift work is associated with high levels of diastolic blood pressure and triglyceride. This association could be attributable to altered life style like diet or health behaviors or due to an independent effect.