Total Antioxidant Capacity and Malondialdehyde in Depressive Rotational Shift Workers

Shift work is associated with sleep deprivation, occupational stress, and increased risk of depression. Depressed patients show increased oxidative stress. During excessive oxidative stress, Malondialdehyde (MDA) increases and total antioxidant capacity (TAC) decreases in body. This cross-sectional study was conducted to determine the serum level of TAC and MDA among depressed rotational shift workers in Shahid Tondooyan Tehran Oil Refinery. 21-item Beck Depression Inventory was used to measure depression level. The level of TAC and MDA was measured by 8 mL fasting blood sample. MDA was determined by thiobarbituric acid reaction. Serum total antioxidants were measured using the ABTS. Results of this study showed that TAC mean and standard deviation concentration was 2.451 (±0.536)？mg/dL and MDA was 3.725 (±1.098)？mic·mol/L, and mean and standard deviation of depression score and BMI were 14.07 (±3.84) and 24.92 (±3.65)？kg/m2, respectively. Depression score had a positive correlation with rotational shift work experience and work experience ( and ), respectively, ( ). 1. Introduction Shift work is defined as work scheduled outside the normal daytime working hours (7 AM to 6 PM) [1]. The trend in our society is toward an increasing pattern of shift work and it is essential for many industries such as refineries to have 24-hour work pattern [2]. More than 20 to 30 percent of workers are shift workers [3]. They are forced to work and sleep against normal chronobiological rhythms, and as a result the pattern of sleep-wake becomes misaligned [4]. Shift work can alter human Circadian system which is normally synchronized with the solar day [5]. Shift workers can never be adapted to their sleep/activity cycle, which is necessary for their work shift. They sleep at times their organism is set to activity and they work when physical effectiveness is low [6]. Disruption of normal circadian system can cause physiological and psychological problems. Shift work also negatively impacts workers’ health condition [7] and cause diseases resulting in absenteeism from work. Sleep disorders are among the health problems caused by shift work [8]. The prevalence of difficulty initiating sleep is higher in rotational shift workers compared with regular day workers [9]. Based on different studies, shift workers complaining about sleep disorders and insufficient sleep range from 10% to 90% [10–12]. Furthermore, sleep disorders and occupational stress lead to more sleepiness and reduce neurobehavioral function consequently, and, therefore, increase the risk of depression [13].